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To characterize higher-order aberrations (HOAs) in clinical and subclinical keratoconus (KC).The study included 33, 36, and 26 patients with clinical, topographic (no clinical signs), and pretopographic (normal topography and no clinical signs) KC and 30 controls. Ocular and corneal HOAs for the 4-mm pupils were measured using a wavefront sensor and expanded up to the sixth order of Zernike polynomials. The magnitudes of trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were calculated via Zernike vector analysis and used as HOA parameters along with total HOAs. Area under the receiver operating characteristic curve (AUROC) values for each wavefront parameter for pretopographic KC were compared.Control eyes and eyes with pretopographic KC had significantly lower ocular or corneal total HOAs and Zernike vector terms than those with clinical KC and topographic KC, except for ocular tetrafoil between topographic KC and pretopographic KC and spherical aberration among all groups. The AUROCs for corneal total HOAs and corneal coma for pretopographic KC and control eyes were 0.781 (100% sensitivity and 47% specificity) and 0.735 (73% sensitivity and 73% specificity), respectively.Corneal total HOAs and corneal coma exhibited a potential ability to discriminate pretopographic KC from normal control eyes.

PURPOSE To assess the role of corneal densitometry and wavefront aberrations post Descemet stripping automated endothelial keratoplasty (DSAEK) and their correlation with visual acuity. METHODS Twenty-seven eyes of 25 patients with nonresolving corneal edema for more than 3 months as a result of Fuchs endothelial corneal dystrophy, pseudophakic bullous keratopathy, or secondary endothelial dysfunction were enrolled in a prospective interventional study and underwent DSAEK. Postoperative evaluation for corneal aberrations, including Higher order aberrations (HOAs) and corneal densitometry (CD), was performed using anterior-segment optical coherence tomography (Avanti RTvue XR; Optovue) and Scheimpflug imaging (Pentacam, Oculus Optikgerate GmbH, Wetzlar, Germany) at 6 months. A correlation analysis of corneal aberrations, including HOAs and CD, with postoperative best-corrected visual acuity at 6 months was performed. RESULTS Mean best-corrected visual acuity (BCVA) improved from 1.67±0.53 log of minimum angle of resolution (logMAR) to 0.2±0.22 logMAR post DSAEK at 6 months (P≤0.0001). At 6 months, mean root-mean-square (RMS) total corneal aberrations (includes HOA and low-order aberration [LOA]), RMS total HOA, and RMS LOA of the central 6-mm zone were 4.99±2.64, 1.80±0.9, and 4.55±2.64, respectively. The mean corneal densitometry from anterior, central, and posterior zones were 39.12±12.77, 23.9±7.2, and 13.54±2.04 gray scale units, respectively. Total anterior aberrations (r=0.051; P=0.006), anterior LOA (r=0.049; P=0.009), total corneal aberrations (r=0.051; P=0.001), total HOAs (r=0.095; P=0.057) and LOAs (r=0.050; P=0.002), and total CD from 0 to 2 mm (r=0.010; P=0.038) and 2 to 6 mm (r=0.014; P=0.018) showed a significant inverse correlation with postoperative BCVA. CONCLUSION There was an inverse relationship between post DSAEK BCVA and total corneal HOAs and full-thickness densitometry at 6 months. Scheimpflug imaging with added tools for corneal aberration and densitometry analysis gives further insight into the suboptimal vision achieved despite transparent corneas post DSAEK.

PURPOSE The purpose of this study was to evaluate the efficacy and safety of implantation of a new continuous corneal ring in keratoconic corneas of an Iranian population. METHODS This study was conducted on 95 contact lens-intolerant keratoconic eyes with clear central corneas. A continuous corneal ring, annular intrastromal corneal inlay (AICI), was inserted using femtosecond laser in all cases. Patients were followed up for 1, 3, and 12 months postsurgery. Visual and subjective refractive outcomes were evaluated in each examination. Besides, keratometry and aberrometric values were recorded before and 12 months after surgery. Finally, vector analysis of refractive astigmatism was performed using the Alpins method. RESULTS The uncorrected and corrected distance visual acuities improved significantly 12 months after surgery from 0.91 ± 0.39 to 0.38 ± 0.22 (P < 0 0.001) and 0.33 ± 0.21 to 0.13 ± 0.11 logMAR (P < 0.001), respectively. Moreover, spherical and cylindrical refractive components reduced from -2.52 ± 2.62 to -0.76 ± 1.78 D (P < 0.001) and -4.14 ± 1.64 to -1.91 ± 1.18 D (P < 0.001), respectively. The mean anterior keratometry had a significant reduction 12 months after AICI insertion (P< 0.001). Primary coma and spherical aberration values showed a significant increase (both, P < 0.05). Our results showed 100% safety (safety index: 1.8) and 45% efficacy (efficacy index: 1). CONCLUSIONS AICI implantation seemed to be a safe and effective procedure for improving visual acuity and refractive outcomes in subjects with keratoconus.

SIGNIFICANCE The SVOne may prove useful to quickly and easily assess refractive correction needs in community screenings and low-resource settings, but not all subjects were testable with the device. PURPOSE This study aimed to compare the SVOne handheld, smartphone-based wavefront aberrometer with a tabletop autorefractor in identifying refractive errors in elderly subjects. METHODS Participants 50 years or older at community eye screenings with visual acuity worse than 20/40 in either eye underwent autorefraction followed by two SVOne trials. Power vectors of right eye data were analyzed. RESULTS Of 84 subjects who underwent autorefraction, 67 (79.8%) were successfully autorefracted with the SVOne, of whom 82.1% (55/67) had a successful repeat reading. Mean M (spherical equivalent) values from tabletop and handheld autorefraction were -0.21 D (95% confidence interval [CI], -0.71 to +0.29 D) and -0.29 D (95% CI, -0.79 to +0.21 D), respectively (P > .05). Mean astigmatism values from tabletop and handheld devices were +1.06 D (95% CI, 0.87 to 1.26 D) and +1.21 D (95% CI, 0.99 to 1.43 D), respectively (P > .05). Intraclass correlation coefficients between devices were 0.95 (95% CI, 0.93 to 0.97) for M, 0.78 (95% CI, 0.66 to 0.86) for J0, and 0.45 (95% CI, 0.24 to 0.63) for J45 (P < .05 for all). Excellent test-retest correlation between SVOne measurements was noted for M (Pearson correlation [r] = 0.96; P < .05), but a weaker correlation was noted for J0 and J45 (r = 0.67 and r = 0.63 [P < .05 for both], respectively). CONCLUSIONS The SVOne provided strong agreement for M, with the majority of readings within ±1.00 D of each other, when compared with the tabletop autorefractor. A weaker but still good correlation was noted for astigmatism. Similar findings were noted when assessing repeatability.

PURPOSE To study the change in contrast sensitivities in eyes with Fuchs endothelial dystrophy and bullous keratopathy after Descemet membrane endothelial keratoplasty (DMEK). METHODS In this prospective study, 50 pseudophakic eyes of 50 patients who received DMEK surgery at the Charite-Universitatsmedizin Berlin were included. Visual acuity; contrast sensitivity using OPTEC 6500 at spatial frequencies of 1.5, 3, 6, 12, and 18 cycles/degree in photopic and mesopic light with and without glare; central corneal thickness (CCT); and anterior and posterior corneal aberrations were measured preoperatively and at 3 and 12 months postoperatively. RESULTS Best-corrected visual acuity (preoperative 0.67 ± 0.46 and after 12 months 0.19 ± 0.16 LogMAR, P < 0.001) and photopic and mesopic contrast sensitivities with and without glare improved significantly, whereas CCT decreased significantly (preoperative 677 ± 114 μm, after 12 months 527 ± 29 μm, P < 0.001). Preoperative CCT correlates significantly with preoperative photopic contrast sensitivity (correlation coefficient -0.462, P = 0.002), and postoperative total anterior aberrations correlates with postoperative photopic contrast sensitivity (correlation coefficient -0.361, P = 0.006). CONCLUSIONS Photopic and mesopic contrast sensitivities, especially with glare, are impaired in patients with Fuchs endothelial dystrophy and bullous keratopathy. The extent of the corneal thickening seems to mainly influence the contrast sensitivity preoperatively. DMEK surgery improves the contrast sensitivity significantly. However, higher postoperative anterior corneal aberrations limit the postoperative contrast sensitivities.

PURPOSE To compare uncorrected distance visual acuities (UDVAs) and induced higher-order aberrations (HOAs) in the early postoperative period between low-energy (LE) small-incision lenticule extraction (SMILE), high-energy (HE) SMILE, and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) procedures. SETTING University based refractive surgery center. STUDY DESIGN Retrospective cohort study. METHODS Records of patients who underwent SMILE or FS-LASIK were retrospectively reviewed. SMILE patients were separated into 2 groups: HE settings (125 nJ, 3.0 μm spot spacing) and LE settings (125-130 nJ, 4.5 μm spot spacing). UDVA was measured at postoperative day (POD) 1. Corneal HOAs and UDVA were measured at postoperative month (POM) 1. Induced spherical aberration, vertical coma, horizontal coma, total coma, and total HOAs were calculated. RESULTS The study included 147 eyes of 106 patients, 49 in each group. For SMILE patients, the difference in mean UDVA at POD1 was highly statistically significant in favor of the LE group (-0.003 vs 0.141, P < .0001). No significant difference in mean UDVA at POD1 was noted between the LE group and FS-LASIK group (-0.003 vs -0.011, P = .498). Induced change in spherical aberration was less in LE SMILE than that in FS-LASIK (0.136 vs 0.186 μm, P = .02) at POM1. No significant differences in POM1 mean UDVA (-0.033 vs -0.036) or induced change in all other HOAs were noted between LE SMILE and FS-LASIK. CONCLUSIONS LE settings were associated with significantly improved POD1 UDVA. POD1 and POM1 UDVA were comparable with those of FS-LASIK. Spherical aberration induction was less with LE SMILE than that with FS-LASIK, whereas all other induced HOAs were comparable with FS-LASIK.

Significance Fitting specialty contact lenses (hybrid and miniscleral) can be a useful option in keratoconus patients to decrease higher-order aberrations (HOAs) and increase the quality of vision. Purpose The aim of the present study was to compare corneal HOAs between miniscleral and hybrid lenses in keratoconus patients. Methods The target population of this study was 37 patients with bilateral keratoconus aged 20 to 35 years who were referred to a specialized contact lens clinic by a corneal specialist. Pre-fitting examinations included objective and subjective refraction, measurement of uncorrected and best spectacle-corrected visual acuity, and measurement of corneal HOAs. Lens fitting was performed in the next step. Finally, post-fitting measurements including contact lens-corrected visual acuity and corneal HOAs were performed. Results The root mean square of the total HOAs significantly decreased after fitting both miniscleral and hybrid lens designs. There was a significant change in the third-order vertical coma and spherical aberration after fitting the miniscleral lens. In the hybrid lens group, a significant change was found only in vertical coma after fitting. There was no significant difference in the post-fitting HOA change between the two groups. Conclusions The results of this study showed the effectiveness of both miniscleral and hybrid lenses in decreasing HOAs in keratoconus patients. No significant difference was observed between these two lenses in this regard.

PURPOSE To evaluate the safety and efficacy of photorefractive intrastromal corneal crosslinking (PiXL) for the treatment of low myopia using the epithelium-on approach with supplemental oxygen. SETTING The Eye Foundation, Coimbatore, India. DESIGN Prospective interventional case series. METHODS Myopic nonectatic eyes underwent PiXL using the Mosaic system. Ultraviolet-A (UV-A) irradiation of 365 nm wavelength was delivered in an accelerated (30 mW/cm) pulsed approach to provide a total fluence of 15 J/cm. Supplemental oxygen (concentration greater than 95%) was provided to increase the efficacy of the epithelium-on approach during the UV-A irradiation. Efficacy was determined by improvement in mean refractive spherical equivalent (MRSE), uncorrected distance visual acuity (UDVA), and keratometric flattening. Safety was determined by loss of lines of corrected distance visual acuity, endothelial cell loss, and adverse events. RESULTS Fifty eyes of 26 patients with a mean age of 22.73 ± 3.74 years were included. A significant improvement in UDVA from baseline (logarithm of the minimum angle of resolution [logMAR] 0.63 ± 0.25) was noted at the 3-month (logMAR 0.08 ± 0.15) and 6-month (logMAR 0.13 ± 0.18) follow-up visits (P < .001). Significant keratometric flattening from baseline was noted at all follow-up visits (P < .001). No significant endothelial cell loss or adverse effects were noted. A significant correlation was noted between the change in MRSE and preoperative corneal biomechanics (deformation amplitude ratio, P = .029). CONCLUSIONS Transepithelial PiXL with supplemental oxygen might be a safe and effective approach for reduction of myopia. The change in MRSE and keratometric flattening was greater in comparison with earlier protocols, including the epithelium-off approach.

Purpose To study the effect of pupil centroid shift (PCS) compensation on lower- and higher-order aberrations (HOAs) after photorefractive keratectomy (PRK). Setting Labbafinejad Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Design Prospective intrasubject fellow eye study. Methods One hundred twelve eyes of 56 patients with simple myopia or myopic astigmatism scheduled for PRK were enrolled. Preoperatively, the amount of PCS was measured in the horizontal and vertical directions. All eyes received wavefront-optimized treatment with static cyclotorsion compensation. PCS compensation was turned on for the right eye of each subject (PCS-on group), and turned off for the left eye (PCS-off group). Postoperatively, refraction and corneal HOAs were compared between the study groups at 6 months. Results Mean preoperative myopia was -3.84 diopters (D) ± 2.41 (SD) vs -3.75 ± 2.27 D (P = .408), whereas mean preoperative cylinder was -1.18 D ± 1.15 (SD) vs -1.14 ± 1.16 D (P = .769) in the PCS-on and PCS-off groups, respectively. Mean absolute PCS values were 62.25 μm ± 41.82 (SD) vs 55.92 ± 37.47 μm (P = .45) in the horizontal direction and 65.04 ± 47.16 μm vs 58.40 ± 45.44 μm in the vertical direction (P = .29) in the PCS-on and PCS-off groups, respectively. The study groups were comparable in terms of postoperative refraction and root mean square of total corneal HOAs. Conclusions Compensation of PCS did not affect lower- and higher-order aberrations after wavefront-optimized PRK with static cyclotorsion compensation in myopic or myopic astigmatic eyes.

PURPOSE To identify factors associated with a successful wavefront-guided customized treatment (WG-CT) with an excimer laser in highly aberrated corneas. SETTING VISSUM Alicante Spain. DESIGN Retrospective consecutive noncomparative case series. METHODS Treatment was performed with the WG-CT Amaris excimer laser using the ORK-CAM software for the calculation of the ablation profile. Eyes of patients with significantly aberrated corneas, including postrefractive and keratoplasty procedures or high irregular astigmatism with significant higher-order aberrations (HOAs) that had WG-CT were included. Refractive outcomes, HOAs, and visual outcomes were recorded. Statistical analysis was performed to identify factors associated with technical (based on HOAs) or refractive outcome success. RESULTS The study included 55 treatments of 51 eyes (35 patients). The postoperative uncorrected distance visual acuity was 0.2 logarithm of the minimum angle of resolution or better in 72% of the eyes, and the postoperative residual manifest refraction spherical equivalent was ±0.50 diopter in 56% of the eyes, whereas 11% of the eyes lost 1 line or more in corrected distance visual acuity. Successful reduction in the total root mean square (RMS) of HOAs occurred in 36 eyes (65%), and these eyes had a significantly higher preoperative RMS of HOAs (1.45 ± 0.93 μ vs 0.91 ± 0.34 μ, P = .003) and preoperative coma-like aberrations (1.09 ± 0.83 μ vs 0.55 ± 0.28 μ, P = .001). In multivariate analysis, posthyperopic treatment eyes were less likely to achieve refractive outcome success (odds ratio = 0.09, P = .02). CONCLUSIONS WG-CT in highly aberrated corneas had a limited refractive predictability. Eyes with preoperative coma-like aberrations are more likely to benefit from a reduction in HOAs. Posthyperopic treatment is associated with a higher rate of refractive surprises.

To compare uncorrected distance visual acuity (UDVA) and patient-reported outcomes with a new silicone corneal shield and a conventional bandage contact lens (BCL) after photorefractive keratectomy (PRK).Stanford Eye Laser Center (Palo Alto, California) and SladeBaker Vision (Houston, Texas).Prospective randomized cohort study.Standardized bilateral wavefront-guided or wavefront-optimized PRK was performed in 25 patients with myopia. Each patient's dominant eye was randomized to either a silicone corneal shield or a conventional BCL, which was placed at the conclusion of surgery. The contralateral eye was assigned the other intervention. The UDVA and patient-reported outcomes were measured preoperatively, 1 hour after surgery, and at 1, 2, 3, 4, and 7 days postoperatively.At 1 day postoperatively, the mean logarithm of the minimum angle of resolution (logMAR) UDVA was 0.04 ± 0.16 (SD) in the silicone corneal shield group and 0.29 ± 0.22 in the BCL group (P 0.01). At 7 days postoperatively, the mean logMAR UDVA was 0.09 ± 0.17 in the silicone corneal shield group and 0.23 ± 0.24 in the BCL group (P = .01). At 1 day through 3 days postoperatively, the patients reported greater pain, discomfort, foreign body sensation, and heavy eyelid in the eye with the silicone corneal shield. There was no statistically significant difference in the survey outcomes between the two groups at 4 days and 7 days postoperatively.The new silicone corneal shield was safe and effective, with faster visual recovery and a trend toward quicker epithelialization; however, it might be less comfortable than a conventional BCL.

Significance Measurement of ocular aberrations is a critical component of many optical corrections. Purpose This study examines the accuracy and repeatability of a newly available high-resolution pyramidal wavefront sensor-based aberrometer (Osiris by Costruzione Strumenti Oftalmici, Firenze, Italy). Methods An engineered model eye and a dilated presbyopic eye were used to assess accuracy and repeatability of aberration measurements after systematic introduction of lower- and higher-order aberrations with calibrated trial lenses (sphere +10.00 to -10.00 D, and astigmatic -4.00 and -2.00 D with axis 180, 90, and 45°) and phase plates (-0.57 to 0.60 μm of Seidel spherical aberration defined over a 6-mm pupil diameter). Osiris aberration measurements were compared with those acquired on a previously calibrated COAS-HD aberrometer for foveal and peripheral optics both with and without multizone dual-focus contact lenses. The impact of simulated axial and lateral misalignment was evaluated. Results Root-mean-square errors for paraxial sphere (corneal plane), cylinder, and axis were, respectively, 0.07, 0.11 D, and 1.8° for the engineered model and 0.15, 0.26 D, and 2.7° for the presbyopic eye. Repeatability estimates (i.e., standard deviation of 10 repeat measures) for the model and presbyopic eyes were 0.026 and 0.039 D for spherical error. Root-mean-square errors of 0.01 and 0.02 μm, respectively, were observed for primary spherical aberration and horizontal coma (model eye). Foveal and peripheral measures of higher- and lower-order aberrations measured with the Osiris closely matched parallel data collected with the COAS-HD aberrometer both with and without dual-focus zonal bifocal contact lenses. Operator errors of focus and alignment introduced changes of 0.018 and 0.02 D/mm in sphere estimates. Conclusions The newly available clinical pyramidal aberrometer provided accurate and repeatable measures of lower- and higher-order aberrations, even in the challenging but clinically important cases of peripheral retina and multifocal optics.

To evaluate changes in corneal higher-order aberrations (HOAs) on the anterior and posterior corneal surfaces after 1.8 mm microincision cataract surgery (MICS) and 2.8 mm small-incision cataract surgery (SICS).Eye Department, First Affiliated Hospital, School of Medicine, Zhejiang University, China.Prospective case series.Right eyes of patients had MICS or SICS. The preoperative and 1-week and 3-month postoperative distance visual acuity (CDVA) and dry eye-related indices were determined. The corneal total HOAs and Zernike coefficients (3rd and 4th order) over 4.0 and 6.0 mm zones, corneal volume, central corneal thickness (CCT), and anterior and posterior corneal astigmatism were measured using a Pentacam HR analyzer.The MICS group comprised 126 eyes and the SICS group 70 eyes. The MICS and SICS groups had similar postoperative CDVA; however, the MICS group had quicker recovery of CCT, corneal volume, and corneal astigmatism. Significantly increased anterior corneal total HOAs were observed in the SICS group over a 6.0 mm zone (P .001). Both groups showed significantly increased posterior corneal total HOAs over both zones (P .001). Similar changing patterns in individual Zernike terms were observed. The MICS group had quicker recovery of posterior corneal surface coma and trefoil than the SICS group, especially over the 6.0 mm zone. Changes in posterior corneal surface total HOAs were correlated with corneal volume changes (P .01).The data suggest quicker corneal recovery and less change in total and anterior corneal surface corneal HOAs after MICS. Changes in posterior corneal surface HOAs were more pronounced in both surgical groups.

Purpose To evaluate the induced ocular aberrations after cataract surgery with extreme low- powered and high-powered spherical monofocal intraocular lenses (IOLs) using a new pyramidal wavefront sensor aberrometer. Setting Vissum Instituto Oftalmologico, Alicante, Spain. Design Prospective observational comparative study. Methods This study included patients who had cataract surgery with implantation of a spherical monofocal IOL. The patients were divided into three groups according to the IOL power. Group 1: +20 diopters (D) to +23 D; Group 2: less than +10 D; and Group 3: +29 D or more. Assessment after 3 months included: uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, contrast sensitivity function test (Ginsburg), corneal aberrometry, and total ocular aberrometry with a pyramidal wavefront sensor aberrometer (Osiris) for 4.0 mm, 4.5 mm, and 5.0 mm pupil diameters. Results The study comprised 88 eyes of 56 patients. There were no differences between all groups in terms of refractive error, corneal aberrometry, or total ocular higher-order aberrations at any analyzed pupil diameter. The ocular spherical aberration (SA) was not significantly different between groups with a 4.0 mm pupil. The SA was significantly lower in Group 2 when compared with Group 1 and Group 3 for both 4.5 mm (P = .01 and P = .001, respectively) and 5.0 mm (P = .002 and P = .002, respectively). There was no significant difference in SA between Group 1 (+20 D to 23 D) and Group 3 (≥+29 D) at any analyzed pupil diameter. Higher SA did not correlate to lower contrast sensitivity. Conclusions Despite the theoretical evidence, only a negligible amount of clinically insignificant aberrations were induced by high-powered positive IOLs. Low-powered IOLs did not induce significant levels of SAs.

To compare the outcomes of topography-guided and wavefront-optimized surgery in patients having laser in situ keratomileusis (LASIK) for myopia.Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, and BALGEUN-EYE21 Operation Center, Gwangju, South Korea.Prospective case study.Patients had topography-guided LASIK in 1 eye and wavefront-optimized LASIK in the contralateral eye using Contoura Vision software and the WaveLight EX500 excimer laser. Refractive and visual outcomes were analyzed 3 months postoperatively.The study comprised 43 patients. In both groups, the postoperative uncorrected distance visual acuity (UDVA) was 0.0 logarithm of the minimum angle of resolution or better in 90.7% of eyes and the residual spherical equivalent (SE) refractive error was ±0.75 diopter (D) in 81.4% of eyes. The UDVA, residual SE refractive error, and astigmatism did not differ significantly between the 2 groups. There was significant induction of higher-order aberrations (HOAs) in both groups, although corneal coma and trefoil did not increase and ocular trefoil decreased significantly in the topography-guided group (P = .038). However, in the wavefront-optimized group, corneal coma and trefoil increased significantly (P .001 and P = .046, respectively) and ocular trefoil did not change significantly. In addition, topography-guided LASIK induced significantly fewer corneal total HOAs (P .001), coma (P .001), and trefoil (P = .020) than wavefront-optimized LASIK.Although both topography-guided LASIK and wavefront-optimized LASIK safely and effectively achieved the predicted refractive and visual outcomes, topography-guided LASIK induced fewer HOAs and significantly decreased ocular trefoil, corneal total HOAs, and coma.

This technique of performing pinhole pupilloplasty helps filter the straylight from the periphery of the cornea in cases with higher-order corneal aberrations. The pinhole effect blocks distorted and unfocused light rays and isolates more focused central and paracentral rays through the central aperture, thereby reducing aberrations of the optical system as a whole and enhancing visual acuity and its image quality.

Purpose To compare the effect of decentration and tilt on the optical performance of 6 aspheric intraocular lens (IOL) designs in a model eye. Setting Department of Ophthalmology, Graduate School of Medicine, Dokkyo Medical University, Tochigi, Japan. Design Experimental study. Methods In theoretical simulations, the amount of spherical aberration in the IOL was varied to produce residual ocular spherical aberration (range −0.15 to 0.30 μm) at a 6.0 mm entrance pupil. Wavefront aberration analyses were performed with the ZEMAX optical design program (version August 20, 2014) to obtain the ocular root-mean-square values of astigmatism, coma, trefoil, and higher-order aberrations (HOAs) when the IOL was centered on the insertion position and misaligned at a 4.0 mm entrance pupil. The retinal visual images were calculated using the same conditions. Six 20.0 diopter (D) aspheric IOLs and one 20.0 D spherical IOL were used for the experimental studies. Each IOL was inserted in the model eye. The actual alignments were measured using a Scheimpflug camera (EAS-1000). The wavefront aberrations and visual images were gauged using a wavefront analyzer (KR-1W) at several IOL alignments. Results Intraocular lens decentration and tilt increased wavefront aberrations and degraded optical performance. Astigmatism, coma, and HOAs generated by misaligned IOLs were related to the amount of spherical aberration correction of the IOLs. The extent of spherical aberration remained unchanged by the amount of misalignment. Experimental model eye results showed trends similar to theoretical results. Conclusions The spherical aberration correction amount in the aspheric IOL design was critical for the astigmatism, coma, and HOAs generated by the IOL misalignment. Additional spherical aberration corrections led to a more sensitive optical performance degradation resulting from IOL misalignment.

To compare higher order aberrations (HOAs) in normal eyes between a Scheimpflug imaging system (Pentacam HR) and dual Scheimpflug-Placido imaging system (Galilei G4).Emory University, Atlanta, Georgia, and the University of Southern California, Los Angeles, USA.Retrospective case series.Eyes screened for refractive surgery were evaluated sequentially using a Scheimpflug device and a dual Scheimpflug-Placido device. Differences, correlations, and agreement between values for total root mean square (RMS), trefoil, coma, and spherical aberration were analyzed, and Bland-Altman plots were generated.One hundred five eyes of 105 patients (44 men, 61 women) were evaluated. Total RMS, coma, and trefoil were significantly different between groups (all P .001), while spherical aberration values were not. There was moderate correlation between devices for trefoil (r = 0.475 to 0.652), coma (r = 0.574 to 0.651), and spherical aberration (r = 0.483) and a strong correlation for total cornea RMS (r = 0.817). There was no directional bias between groups. The 95% limits of agreement for absolute values was 0.039 μm for trefoil at 30 degrees, 0.405 μm for trefoil at 0 degree, 0.553 μm for horizontal coma, 0.545 μm for vertical coma, 0.318 μm for spherical aberration, and 0.617 μm for RMS.A Scheimpflug imaging device and dual Scheimpflug-Placido imaging device generated statistically different values for total cornea HOAs; however, the correlation between devices was moderate to strong and there was reasonable agreement in all measures for normal eyes. Based on these findings, the devices appear functionally equivalent for clinical use, although caution is warranted for outcomes-based research protocols that report HOAs.

Significance Visual performance with wavefront-guided (WFG) contact lenses has only been reported immediately after manufacture without time for habituation, and comparison has only been made with clinically unrefined predicate conventional lenses. We present comparisons of habitual corrections, best conventional scleral lenses, and WFG scleral lenses after habituation to all corrections. Purpose The purpose of this study was to compare, in a crossover design, optical and visual performance of eyes with corneal ectasias wearing dispensed best conventional scleral lens corrections and dispensed individualized WFG scleral lens corrections. Methods Ten subjects (20 eyes) participated in a randomized crossover study where best conventional scleral lenses and WFG scleral lenses (customized through the fifth radial order) were worn for 8 weeks each. These corrections, as well as each subject's habitual correction and normative data for normal eyes, were compared using (1) residual higher-order aberrations (HORMS), (2) visual acuity (VA), (3) letter contrast sensitivity (CS), and (4) visual image quality (logarithm of the visual Strehl ratio, or logVSX). Correlations were performed between Pentacam biometric measures and gains provided by WFG lenses. Results Mean HORMS was reduced by 48% from habitual to conventional and 43% from conventional to WFG. Mean logMAR VA improved from habitual (+0.12) to conventional (-0.03) and further with WFG (-0.09); six eyes gained greater than one line with WFG over conventional. Area under the CS curve improved by 26% from habitual to conventional and 14% from conventional to WFG. The percentage of the eyes achieving normal levels were as follows: HORMS, 40% for conventional and 85% for WFG; VA, 50% for conventional and 85% for WFG; and CS, 60% for conventional and 90% for WFG. logVSX improved by 16% from habitual to conventional and 25% further with WFG. Reduction in aberrations with WFG lenses best correlated with posterior cornea radius of curvature. Conclusions Visual performance was superior to that reported with nonhabituated WFG lens wear. With WFG lenses, HORMS and logVSX significantly improved, allowing more eyes to reach normal levels of optical and visual performance compared with conventional lenses.

To compare the outcomes of conventional phacoemulsification and femtosecond laser-assisted cataract surgery followed by multifocal intraocular lens (IOL) implantation.Asan Medical Center, Seoul, South Korea.Retrospective case series.Depending on their preference, patients had femtosecond laser-assisted cataract surgery or conventional phacoemulsification. Patients in the femtosecond group with corneal astigmatism greater than 0.75 diopter also had arcuate keratotomy. All eyes had multifocal IOL implantation. One month after treatment, the uncorrected distance and near visual acuities, spherical equivalent, corneal and refractive astigmatism, aberrometry results, and questionnaire results were compared between groups. Correlations between target-induced astigmatism (TIA) and surgically induced astigmatism (SIA) were also compared between the groups.The femtosecond group comprised 17 patients (23 eyes), with arcuate keratotomy performed in 14 eyes. The conventional phacoemulsification group comprised 22 patients (26 eyes). In the femtosecond group, the difference in corneal astigmatism between preoperatively and postoperatively was statistically significant. The correlation between TIA and SIA was greater in the femtosecond group. Corneal root-mean-square higher-order aberrations (RMS HOAs) (P .01) and total trefoil (P = .043) were significantly higher in the femtosecond laser group. However, internal total RMS (P = .05), tilt (P = .041), and RMS HOAs (P = .047) were significantly lower in the femtosecond group. Satisfaction scores were significantly higher in the femtosecond group.Astigmatic change was more predictable in the femtosecond laser-assisted cataract surgery group. Internal aberrations, including total RMS, tilt, and RMS HOAs, were lower in the femtosecond group, and patients in that group were more satisfied.

PURPOSE To evaluate the posterior corneal elevation (PCE) and biomechanical changes after small incision lenticule extraction (SMILE) at depths of 110 μm and 130 μm. METHODS One hundred sixteen eyes from 58 consecutive patients who underwent SMILE were included in this prospective study. Each patient underwent SMILE in one eye to a depth of 110 μm and in the other eye to a depth of 130 μm. A Scheimpflug camera and Hartmann-Shack WASCA aberrometer were used to assess the PCE and wavefront aberrations, respectively, before SMILE and at 1 and 3 months after surgery. The PCE was analyzed along 3 optical zones (apex and 2 and 4 mm diameters) as a function of the meridian. Dynamic Scheimpflug imaging was used to evaluate the biomechanics preoperatively and at 1 day, 1 month, and 3 months postoperatively. RESULTS No significant difference was found in either vision correction or corneal biomechanics between the 2 groups. In both groups, the PCE became significantly flattened at the apex and at 2 mm annulus 1 month postoperatively, especially for the 110-μm cap group. Three months postoperatively, the 110-μm cap group was still flattened significantly, whereas the displacement at the apex in the 130-μm cap group had disappeared. There was no significant difference in wavefront aberrations between the groups after surgery, except in the vertical coma (P < 0.001). CONCLUSIONS The differences in corneal biomechanics between the 110-μm cap group and 130-μm cap group were small; however, the superficial lenticule might cause displacement of the PCE to be more persistent in one eye than in the other.

PURPOSE: Corneal changes are prevalent in eyes with primary congenital glaucoma (PCG). This study aimed to describe corneal irregularity and high-order aberrations (HOAs) in PCG eyes. MATERIALS AND METHODS: The study consecutively enrolled 61 PCG eyes (of 39 participants with PCG) and 61 age-matched control eyes (of 61 healthy participants). Participants underwent corneal topography, best spectacle-corrected visual acuity (BSCVA), and fundus photography. Corneal irregularity and HOAs were derived from topographic data and evaluated over central 4 and 6 mm diameter zones. Variables were compared between PCG and control eyes. Percentages of PCG eyes with abnormal corneal irregularity and HOAs were calculated. RESULTS: The median ages of PCG and control participants were 8.8 and 8.6 years, respectively. Irregularity and total HOAs across both 4 and 6 mm zones were greater in PCG than in control eyes. The median irregularity of PCG eyes was 2 to 5 times that of the controls, whereas, their median total HOAs were approximately twice those of the controls. Thirty-nine (64%), 53 (87%), and 40 (66%) PCG eyes had abnormal (either 4 or 6 mm zone) anterior irregularity, posterior irregularity, and total HOAs. Similar percentages were observed among eyes with a cup-to-disc ratio

Purpose To evaluate the differences in corneal higher-order aberrations (HOAs) between cataract patients with high axial myopia and normal cataract patients, and to identify the associated factors. Setting Department of Ophthalmology and Vision Science of the Eye and ENT Hospital of Fudan University, Shanghai, China. Design Retrospective case series. Methods Corneal aberrations and axial lengths (ALs) were measured using a rotating Scheimpflug camera (Pentacam) and partial coherence interferometry (IOLMaster) in the high myopia group and the control group. Results The study comprised 287 patients (520 eyes). There were 194 eyes in the high myopia group and 326 eyes in the control group. The 5 anterior corneal aberrations—vertical coma, vertical trefoil, horizontal coma, oblique trefoil, and primary spherical aberration—in the high myopia group were 0.07 μm ± 0.38 (SD), −0.11 ± 0.23 μm, 0.07 ± 0.28 μm, −0.02 ± 0.18 μm, and 0.39 ± 0.19 μm, respectively. No negative primary spherical aberrations of the total or anterior corneal surface were found in the high myopia group. Differences between the 2 groups were found in terms of central corneal thickness, astigmatism, primary spherical aberration, vertical coma, and oblique trefoil; however, these differences were not consistent between different age subgroups. Higher-order aberrations were correlated with age. Posterior corneal vertical coma was correlated with AL (Pearson correlation = −0.188, P = .047). Conclusions Negative primary spherical aberrations of the anterior or total corneal surface were not found in the high myopia group. Age showed a strong relationship with HOAs. For cataract patients with high myopia, aspheric intraocular lens implantation is recommended.

Purpose To evaluate the correlations between corneal biomechanical indices from dynamic Scheimpflug assessment and optical quality assessed as higher-order aberrations (HOAs) using a Hartmann-Shack ocular wavefront sensor in patients with keratoconus (KC). Methods In this prospective, observational case series, the eyes with KC or KC suspect (KCS) from Osaka University Hospital, Osaka, Japan, were analyzed. Corneal biomechanical assessment was performed using Corvis ST (Oculus Optikgerate GmbH, Wetzlar, Germany), and ocular wavefront aberrations were measured using the KR-1W (Topcon Corp, Tokyo, Japan). Correlations between the biomechanical indices and ocular HOAs were assessed. Corneal biomechanical indices included the deformation amplitude ratio within 2 mm, integrated radius, stiffness parameter at the first applanation, and the linear Corvis Biomechanical Index. Wavefront data of the central 4-mm region were expanded up to the sixth order of Zernike polynomials. The magnitudes of trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were calculated by Zernike vector analysis and then used as ocular HOA parameters along with total HOAs. Results Thirty-four KC eyes and 37 KCS eyes were included. KC eyes showed significant correlations between ocular HOAs and biomechanics, whereas there were few significant correlations in KCS eyes. In KC eyes, deformation amplitude ratio within 2 mm, integrated radius, and Corvis Biomechanical Index beta showed stronger correlations with coma among the wavefront parameters. Conclusions Corneal biomechanical indices correlated with ocular HOAs in patients with KC. In particular, there was a strong association with the increase in coma caused by inferosuperior asymmetry of the shape of the cornea in patients with KC.

PURPOSE To determine which baseline characteristics are associated with vision-related quality of life (QOL) after endothelial keratoplasty. METHODS A patient- and outcome-masked randomized clinical trial. Consecutive patients presenting with isolated endothelial disease requiring endothelial keratoplasty at Oregon Health Sciences University and Stanford University. Study eyes randomized to one of the 2 types of endothelial keratoplasty were given the national eye institute vision function questionnaire 25 at baseline and 12 months. In this prespecified secondary outcome, we assessed the role of recipient and donor characteristics as predictors of the 12-month national eye institute vision function questionnaire 25 change score. RESULTS The mean vision function questionnaire (VFQ) score was 74 (SD 14) at baseline and increased to 82 (SD 12) at 3 months and 87 (SD 10) at 12 months. We were unable to find a difference in vision-related QOL in study participants who underwent Descemet membrane endothelial keratoplasty compared with ultrathin Descemet stripping endothelial keratoplasty [coef -0.98, 95% confidence interval (CI) -9.27 to 7.31; P = 0.82]. In multivariable analysis, patients who underwent endothelial keratoplasty in 2 eyes had approximately 8 points higher VFQ at 12 months after the second eye than those who had only one eye enrolled (95% CI 0.10-15.72; P = 0.047). Posterior densitometry produced an approximately 1-point increase each in the VFQ change score for each 1 grayscale unit increase at baseline (95% CI 0.26-1.81; P = 0.009). Although the sample size was small, a diagnosis of pseudophakic bullous keratopathy had approximately 19-points more improvement on average compared with Fuchs (95% CI 7.68-30.00; P = 0.001). CONCLUSIONS Bilateral endothelial keratoplasty resulted in higher vision-related QOL compared with unilateral. Baseline densitometry, objective measure of corneal haze that predicts vision-related QOL, may play a role in monitoring disease progression.

PURPOSE: To analyze the variation in vertical coma and the rest of ocular aberrations before and after fitting prismatic soft contact lenses (PSCL). METHODS: Thirty-seven eyes of 20 healthy subjects (24.30±2.03 years) were evaluated to analyze the variation in ocular wavefront aberrations before and after fitting PSCL of different base-down prism values (1.0, 1.5, and 2.0 prism diopters [PD]), designed to study its influence in the compensation of vertical coma aberration. A Hartmann-Shack sensor with a wavelength of 780 nm was used, considering a pupil size of 3 mm. In addition, the influence of PSCL in visual function under photopic conditions in terms of high-contrast visual acuity and contrast sensitivity was evaluated. RESULTS: There was statistically significant differences (P

To investigate the changes in anterior and posterior corneal irregularity after Descemet membrane endothelial keratoplasty (DMEK).This retrospective study included 27 eyes of 23 patients who underwent DMEK and 27 eyes of age-matched healthy controls. Corneal irregularity indexes, surface regularity of height (SR_H), and higher-order aberrations were evaluated in 4- and 6-mm diameters of the cornea, preoperatively and postoperatively, using anterior segment optical coherence tomography.The best spectacle-corrected visual acuity (logarithm of the minimum angle of resolution) improved from 1.01 ± 0.54 preoperatively to 0.08 ± 0.11 at 6 months postoperatively. Anterior SR_H was significantly lower at 6 months postoperatively [from 1.86 ± 0.73 to 1.20 ± 0.34 (P0.01) (4-mm) and from 2.29 ± 0.62 to 1.64 ± 0.42 (P0.01) (6-mm)]. Posterior SR_H showed a significant decrease from 6.87 ± 4.19 to 2.18 ± 0.51 (4-mm) and from 5.21 ± 2.60 to 2.44 ± 0.38 (6-mm) at 6 months postoperatively (P0.001). The SR_H was positively correlated with best spectacle-corrected visual acuity (anterior 4 mm: R = 0.524; anterior 6 mm: R = 0.477; posterior 4 mm: R = 0.655; posterior 6 mm: R = 0.655, P0.001) and with higher-order aberrations for 4-mm and 6-mm diameters (R = 0.511 and R = 0.325, P0.001, respectively).The SR_H reflects corneal irregularity and is correlated with the visual outcome after DMEK, which may be very helpful to corneal surgeons as an index indicating the severity before DMEK, and the quality of visual function after DMEK.

To evaluate the changes in corneal higher-order aberrations (HOAs) after corneal wavefront-guided transepithelial photorefractive keratectomy (PRK) and small-incision lenticule extraction (SMILE).Yonsei University College of Medicine and Eyereum Eye Clinic, South Korea.Retrospective case series.Medical records of patients having either corneal wavefront-guided transepithelial PRK or small-incision lenticule extraction were examined. The root-mean-square total HOAs, 3rd-order coma aberration, and 4th-order spherical aberration were measured preoperatively and 6 months postoperatively. Independent t tests and analysis of covariance were used to compare changes in corneal HOAs between the 2 groups.The study comprised 77 eyes having corneal wavefront-guided transepithelial PRK and 81 eyes having small-incision lenticule extraction. The total HOAs and spherical aberration increased after transepithelial PRK (all P .001), whereas coma aberration was stable after transepithelial PRK. The total HOAs, spherical aberration, and coma aberration increased after small-incision lenticule extraction (P .001 for total HOAs, spherical aberration; P = .004 for coma). At 6 months postoperatively, total HOAs and spherical aberration were significantly larger in the transepithelial PRK group than in the small-incision lenticule extraction group. Coma aberration was larger in the small-incision lenticule extraction group than in the transepithelial PRK group. Spherical aberration induction was significantly smaller in the small-incision lenticule extraction group than in the transepithelial PRK group (P .001), and coma aberration induction was larger in the small-incision lenticule extraction group than in the transepithelial PRK group (P = .011).Small-incision lenticule extraction demonstrated that the induction of total HOAs was comparable to corneal wavefront-guided transepithelial PRK, accompanied by smaller spherical aberration induction and larger coma aberration induction. During small-incision lenticule extraction, surgeons should aim to obtain optimum centration for smaller induction of corneal HOAs.

PURPOSE To evaluate the long-term changes in anterior and posterior corneal irregular astigmatism and curvatures after small incision lenticule extraction (SMILE). METHODS Fifty eyes of 28 patients underwent SMILE for myopic astigmatism. All procedures were performed using the VisuMax® femtosecond laser. A Scheimpflug camera was used for preoperative and 3-year postoperative tomography. Anterior and posterior corneal Fourier parameters (spherical component, regular astigmatism, asymmetry, and irregularity) and curvature data were evaluated and compared within 2 subgroups according to the magnitude of the refractive correction (low myopia group: spherical equivalent (SEQ) ≥ -6 D; high myopia group: (SEQ) < -6 D). Associations between all studied parameters were examined. RESULTS Three years postoperatively, an increase in anterior corneal curvatures and Fourier parameters was detected and the results were strongly correlated with the preoperative SEQ, lenticule thickness, and volume. At the posterior cornea, the flattest radius, corneal astigmatism, spherical component, regular astigmatism, and irregularity decreased only in the high myopia group. A correlation was found between changes in posterior astigmatism and changes in anterior radii (R = 0.349, P = 0.014), SEQ (R = 0.396, P = 0.0049), and lenticule thickness (R = -0.414, P = 0.0031). Moreover, changes in posterior corneal irregularity correlated with the changes in anterior and posterior radii (R = -0.3, P = 0.034, and R = 0.449, P = 0.0012, respectively), changes in preoperative SEQ (R = 0.284, P = 0.0477), and lenticule thickness (R = -0.311, P = 0.0298). CONCLUSIONS Three years after SMILE, there was a reduction of posterior astigmatism in high refractive corrections. This could result in undercorrection in high refractive treatments. Total irregularities increased despite the compensatory effect of the posterior corneal surface.

To evaluate the efficacy and safety of topography-guided transepithelial photorefractive keratectomy (PRK) in a group of patients with post-radial keratotomy (RK) showing irregular corneas.Feiz University Hospital, Isfahan, Iran.Prospective case series.Consecutive patients who had irregular astigmatism after RK with stable refraction and topography for at least 1 year were recruited. All eyes had excimer laser topography-guided single-step transepithelial PRK. The efficacy, safety, predictability, and corneal wavefront aberration changes were assessed 6 months after the surgery. Vector analysis was performed using the Alpins method to evaluate the astigmatic treatment.Twenty-two patients (22 eyes) were enrolled. The patients' ages ranged from 37 to 61 years (45.77 years ± 4.9 [SD]); there were 12 men (54.54%) and 10 women (45.46%). Uncorrected distance visual acuity significantly improved after 6 months of treatment (0.45 ± 0.19 logarithm of the minimum angle of resolution [logMAR] preoperatively and 0.25 ± 0.19 logMAR after 6 months) (P .001). Moreover, the corrected distance visual acuity significantly improved at the end of the study (0.14 ± 0.13 logMAR preoperatively and 0.09 ± 0.11 logMAR after 6 months) (P = .01). Furthermore, the aberrometric values were significantly reduced at the 6-month visit (P .001). The mean of the surgically induced astigmatism was 2.15 ± 1.44 diopters. No significant complication was observed.Topography-guided single-step transepithelial PRK is a safe and effective method for treating the irregular refractive errors in post-RK patients.

To compare the change in ocular higher-order wavefront aberrations (HOAs), visual acuity, and modulation transfer function (MTF) after lens extraction with intraocular lens (IOL) implantation in patients with subluxated lenses.Iladevi CataractIOL Research Centre, Ahmedabad, India.Prospective case series.Eyes with subluxated lenses having lens extraction with IOL implantation were included. Capsular bag fixation with in-the-bag IOL implantation or sutured or sutureless scleral fixation of the IOL was performed. Aberrometry was performed preoperatively and 6 months postoperatively. The following were compared: root-mean-square (RMS) value for total ocular HOAs, coma aberration, spherical aberration, MTF, and corrected distance visual acuity (CDVA).Of the 39 eyes with subluxated lenses, 26 eyes had Cionni ring fixation, 9 had sutured scleral fixation, and 4 had intrascleral fixation of the IOL. The mean preoperative and postoperative values, respectively, were as follows: RMS HOAs, 10.5 μm ± 9.5 (SD) and 4.73 ± 4.6 μm (P .001); coma aberration, 2.46 ± 2.4 μm and 0.11 ± 0.1 μm (P = .03); and spherical aberration, 0.37 ± 0.9 μm and 0.02 ± 0.06 μm (P = .02). The MTF improved significantly in all eyes (mean 0.05 ± 0.02 preoperatively and 0.32 ± 0.16 postoperatively) (P = .005). The CDVA was statistically significant improved 6 months postoperatively.Lens extraction with IOL fixation in eyes with subluxated lenses significantly reduced ocular HOAs and improved the MTF.

PURPOSE To determine the effect of cyclopentolate, tropicamide, and artificial tear drops on higher-order aberrations (HOAs) in normal eyes with OPD-Scan III (Nidek Inc., Tokyo, Japan). METHODS In this study, 189 eyes of individuals aged 20 to 35 years were selected as samples. Inclusion criteria were a corrected visual acuity of 20/20 or better, a minimum size of about 5 mm for the pupil in the dark, hyperopia and myopia less than 5 D, and astigmatism less than 2 D. Moreover, participants with pathological eye problems, a history of intraocular surgery, and ocular diseases affecting the accommodation, pupil size, and corneal surface were excluded. Higher-order aberrations of the participants were assessed by the OPD-Scan III before and after cyclopentolate (Colircuss), tropicamide (Mydrax 0.5%), and artificial tears (Tearlose) drop instillation. RESULTS After instilling cyclopentolate drops, the mean of the total root mean square (RMS) increased from 4.580 to 6.335 D, total spherical aberration increased from 0.155 to 0.381 D, and total coma increased from 0.195 to 0.369 D; the increases were significant for total RMS and total spherical aberration, but a significant relationship was not seen with total coma. After tropicamide, the mean aberrations of total RMS increased from 4.301 to 4.568 D, total spherical aberration increased from 0.146 to 0.160 D, and total coma increased from 0.213 to 0.230 D; the increase was only significant for total coma. On the other hand, after artificial tears, the average of all aberrations decreased in a nonsignificant manner. CONCLUSION Most changes of mean aberrations were related to cyclopentolate drops. Tropicamide and artificial tears had the second and third rank according to their effect on mean errors. As a result, it seems that ocular accommodation is the most important impact on HOA than pupil size. However, the pupil size is the second factor for HOAs.

SIGNIFICANCE This study provides a descriptive characterization of higher-order optical aberrations for the eyes of a larger number of Chinese children and adolescents. PURPOSE To determine the distribution of higher-order aberrations (HOAs) of Han Chinese young subjects with normal vision and their relationship to age. METHODS Children and adolescents, aged from 3 to 17 years, with normal visual acuity were enrolled, and their wavefront aberrations for a 6-mm pupil were evaluated by the Zywave II aberrometer. Their correlations with age were analyzed, and the 95% statistical reference ranges were computed for each Zernike term. RESULTS A total of 1634 eyes (287 for preschool-age children, 897 for school-age children, and 450 for adolescents) were analyzed. There was a significant correlation with age and the root mean square (RMS) of total HOAs (r = 0.256, P < .0001), third-order aberrations (r = 0.062, P = .029), fourth-order aberrations (r = 0.197, P < .0001), fifth-order aberrations (r = 0.067, P = .017), and trefoil-like aberrations (r = 0.100, P < .0001) in the myopic group. There were significant differences in RMS values (except coma-like aberrations, χ = 4.179, P = .124) as well as the Zernike coefficients among three different age groups. Therefore, the 95% statistical normal reference values were calculated separately for three age groups. CONCLUSIONS The RMS value of total HOAs, coma-like, trefoil-like, third-order, fourth-order, and fifth-order aberrations are correlated with age, and the RMS values and Zernike coefficients of aberrations were different in different age stages of the subjects. This study described the distribution of HOAs in children and adolescents and established 95% statistical normal values of HOAs for different ages of children and adolescents by analyzing the HOAs in a large number of the Han Chinese clinical population.

PURPOSE To analyze the changes in anterior and posterior corneal surfaces and aberrations in patients who underwent intracorneal ring segment (ICRS) implantation for the treatment of keratoconus. METHODS Eighty-nine eyes of 59 patients with keratoconus who underwent ICRS implantation were analyzed. All eyes were evaluated using a tomography system combining a Placido disc and Scheimpflug photography before and at least 6 months after surgery. Total, anterior, and posterior corneal aberrations, anterior and posterior sagittal and tangential anterior and posterior curve analysis, keratometry (K), minimum corneal thickness, and anterior chamber depth were analyzed before and after surgery. RESULTS Flattening with a decrease in the cone shape on the anterior corneal surface and steepening in the paracentral area with persistence of cone appearance on the posterior corneal surface were noted in all cases after ICRS implantation. The total corneal higher-order aberrations (HOAs) significantly decreased from 1.09 ± 0.43 to 0.71 ± 0.32 μm, and anterior corneal HOAs significantly decreased from 0.98 ± 0.46 to 0.81 ± 0.37 μm, whereas the posterior corneal HOAs increased from 0.53 ± 0.29 to 0.66 ± 0.25 μm after ICRS implantation (P < 0.05). There was a significant decrease in anterior maximum keratometry, but there was a significant increase in posterior maximum keratometry after ICRS implantation (P < 0.05). CONCLUSIONS The cone shape persists on the posterior corneal surface despite its correction on the anterior corneal surface, leading to a decrease in anterior corneal aberrations and an increase in posterior corneal aberrations after ICRS implantation in eyes with keratoconus.

PURPOSE To compare clinical outcomes of conventional corneal cross-linking (C-CXL) and diluted alcohol and iontophoresis-assisted corneal cross-linking (DAI-CXL) for the treatment of progressive keratoconus (KC). METHODS Ninety-three eyes of 80 patients with KC were treated by C-CXL (n = 47) or DAI-CXL (n = 46). Visual acuity, keratometry, KC indexes, pachymetry, and aberrations were recorded before treatment and 1, 3, 6, and 12 months after treatment. The demarcation line was assessed 1 month after treatment. RESULTS A significant improvement in visual acuity was observed at month 3 and month 6 after DAI-CXL and C-CXL, respectively. A significant decrease in maximum keratometry was observed in both groups at month 6. The front symmetry index significantly improved in both groups after 6 months, whereas the Baiocchi Calossi Versaci index significantly improved only after DAI-CXL at month 12 (P = 0.01). Average keratometry and other KC indexes were stable during 12 months of follow-up. Central corneal thickness decreased by 28.6 and 40.2 μm after DAI-CXL and C-CXL at month 1, respectively (P < 0.01), and it reached baseline at the 12th month (P = 0.14) only in the DAI-CXL group. Higher-order aberrations, coma, and spherical aberration significantly worsened at month 1 (P < 0.01) only after C-CXL; however, they improved significantly at month 12 compared with baseline (P < 0.05) in both groups. The demarcation line was visible in all cases at month 1 at a mean depth of 302 ± 56 μm and 311 ± 57 μm after DAI-CXL and C-CXL, respectively (P = 0.7). CONCLUSIONS The DAI-CXL protocol seems as effective as the C-CXL protocol in halting KC progression after 1 year of follow-up.

To evaluate corneal higher-order aberrations (HOAs) in eyes with corneal scars due to herpes simplex keratitis (HSK).Forty-four eyes of 41 consecutive patients who were diagnosed with corneal scars due to HSK and 18 control eyes were included. HOAs of the anterior and posterior surfaces and the total cornea were analyzed using anterior segment optical coherence tomography. Corneal opacity grades were assigned on the basis of slit-lamp examinations.HOAs within a 4-mm diameter were significantly larger in eyes with HSK (anterior surface, 1.01 ± 1.18 μm; posterior surface, 0.25 ± 0.24; total cornea, 1.00 ± 1.00) compared with controls (0.10 ± 0.02, 0.02 ± 0.00, and 0.09 ± 0.01, respectively; all P0.001). HOAs within a 6-mm diameter were significantly larger in eyes with HSK (anterior surface, 1.87 ± 1.75; posterior surface, 0.42 ± 0.44; total cornea, 1.85 ± 1.46) compared with controls (0.19 ± 0.04, 0.06 ± 0.01, and 0.17 ± 0.03, respectively; all, P0.001). The logarithm of the minimum angle of resolution (logMAR) decreased with the corneal opacity score (0.42 ± 0.61 in grade 1, 1.30 ± 0.96 in grade 2, and 1.58 ± 0.90 in grade 3). LogMAR was significantly correlated with HOAs (R = 0.65, P0.0001). HOAs of the posterior surface increased from 0.15 ± 0.15 in grade 1 to 0.37 ± 0.33 in grade 3 (P = 0.005), whereas there was no difference in HOAs of the anterior surface and the total cornea among the different corneal opacity grades.Increased HOAs of the anterior and posterior surfaces occur in eyes with corneal opacity due to HSK. Larger corneal HOAs are associated with poorer visual acuity.

Dry eye has been believed to be a chronic, symptomatic ocular surface disease that affects vision in a limited manner, because it is difficult to detect visual or optical changes using standard visual acuity testing. In practice, common visual complaints associated with dry eye include fluctuating vision with blinking, blurred vision, glare, and eye fatigue. This review discusses our past and current understanding of visual disturbances in dry eye and the various tools available for assessing visual function or optical quality. Tear film instability and ocular surface damage are key factors in the core mechanism underlying dry eye. The mechanisms of these vision-related subjective symptoms of dry eye based on visual function, particularly wavefront aberrations or light scattering, and the core mechanism of dry eye are described. Tear film instability is associated with decreased stability of postblink higher-order aberrations, leading to "fluctuating vision with blinking" and with increased ocular forward light scattering, leading to "glare." Ocular surface damage in the overlying optical zone (in the central corneal regions), is associated with increased higher-order aberrations and increased corneal backward light scattering that can lead to "blurred vision". "Eye fatigue" occurs when patients with dry eye struggle to see things under such visual symptoms.

PURPOSE To evaluate clinical outcomes after small incision lenticule extraction (SMILE) with different cap thicknesses in thick corneas. METHODS Forty patients with central corneal thickness of more than 560 μm were recruited in this prospective, randomized, masked, paired-eye study. Patients were randomized to receive SMILE with a 120-μm cap thickness in 1 eye and 140-μm cap thickness in the other. Uncorrected and corrected distance visual acuity (CDVA), contrast sensitivity (CS), higher-order aberrations (HOAs), and morphologic modifications of corneal architecture were measured during the 3-month follow-up period. RESULTS Postoperative refractive outcomes, visual outcomes, CS, and the changes in HOAs were similar between both groups. The persistence of brightly reflective particles in the corneal interface layer was 1388.6 ± 219.5/mm in eyes with 120-μm cap thickness and 54.7 ± 8.6/mm in eyes with 140-μm cap thickness (P < 0.001). The hyperreflectivity line at the interface layer almost disappeared in all eyes with 140-μm cap thickness, and it still persisted in 43% of the fellow eyes at 3 months postoperatively. The anterior surfaces of lenticules in the 140-μm cap thickness group exhibited more smoothness than in the 120-μm cap thickness group. CONCLUSIONS There was a lower level corneal wound-healing response after SMILE with a 140-μm cap thickness than with a 120-μm cap thickness, although the thickness of cap creation did not affect visual outcomes by 3 months postoperatively.

PURPOSE: To investigate the operation of the Shin-Nippon/Grand Seiko autorefractor and whether higher-order aberrations affect its peripheral refraction measurements. METHODS: Information on instrument design, together with parameters and equations used to obtain refraction, was obtained from a patent. A model eye simulating the operating principles was tested with an optical design program. Effects of induced defocus and astigmatism on the retinal image were used to calibrate the model eye to match the patent equations. Coma and trefoil were added to assess their effects on the image. Peripheral refraction of a physical model eye was measured along four visual field meridians with the Shin-Nippon/Grand Seiko autorefractor SRW-5000 and a Hartmann-Shack aberrometer, and simulated autorefractor peripheral refraction was derived using the Zernike coefficients from the aberrometer. RESULTS: In simulation, the autorefractor's square image was changed in size by defocus, into rectangles or parallelograms by astigmatism, and into irregular shapes by coma and trefoil. In the presence of 1.0 D oblique astigmatism, errors in refraction were proportional to the higher-order aberrations, with up to 0.8 D sphere and 1.5 D cylinder for ±0.6 μm of coma or trefoil coefficients with a 5-mm-diameter pupil. For the physical model eye, refraction with the aberrometer was similar in all visual field meridians, but refraction with the autorefractor changed more quickly along one oblique meridian and less quickly along the other oblique meridian than along the horizontal and vertical meridians. Simulations predicted that higher-order aberrations would affect refraction in oblique meridians, and this was supported by the experimental measurements with the physical model eye. CONCLUSIONS: The autorefractor's peripheral refraction measurements are valid for horizontal and vertical field meridians, but not for oblique field meridians. Similar instruments must be validated before being adopted outside their design scope.

Objectives To analyze the dynamic relationship between ocular geometrical structure and high-order aberrations (HOAs) in teal-time during accommodation of human eye. Methods A custom-built spectral domain optical coherence tomography (OCT) system with high-speed and ultra-long scan depth was used to image the anterior segment, whereas a Shack-Hartmann wavefront sensor was used to detect the whole-eye aberration. A Badal optometer with switched visual targets was integrated with this system to induce 0 and 3.00 D accommodative stimuli. Three young adult subjects were measured and the structural parameters of anterior segment were measured from OCT images and accommodative response and HOAs were calculated and exponentially fitted in real time during the accommodation. Results The dynamic process from nonaccommodation to 3.00 D accommodation results in reduced pupil diameter, shallower anterior chamber depth, and increased crystalline lens thickness. After an accommodative active time, the RMS of the HOAs changes sharply when an accommodative stimulus is introduced and then tends to be stable. The accommodative response time and velocity are characterized by fitted parameters. The individual differences of changing in HOAs between subjects can be explained by the different sign and changing tendency of certain terms of aberration coefficients in form of Zernike polynomials during the accommodation. Conclusions Based on the integrated ocular measurement platform including OCT system and wavefront sensor, our research demonstrated how the morphology of the human anterior segment affect the aberration in real time during accommodation. The dynamic relationship between them helps us to deeply understand the mechanism of accommodation.

PURPOSE We report transient ocular wavefront and blood glucose data for one patient with acute type 1 diabetes mellitus after the treatment with insulin has been initiated. CASE REPORT The wavefront data for both eyes of a 34-year-old male patient were examined by a Hartmann-Shack wavefront sensor. Refraction data and higher-order aberrations were recorded during 130 days for eyes in natural conditions, without cycloplegia. At the beginning, we sampled data every 3 to 4 days and enlarged the intervals, when values settled. In total, we report 20 measurements and 1 baseline entry. Blood glucose levels were recorded at least six times a day during the complete period. For the equivalent sphere, we recorded a bilateral hyperopic shift of 5 D from -2.75 DS to +2.25 DS, followed by a reverse myopic shift of the same amount. The equivalent sphere peaked about 15 to 18 days after the treatment with insulin had begun. Cylinder values kept remarkably stable. Higher-order aberrations are dominated by the spherical aberration. The Zernike coefficient c12 for both eyes changed substantially from OD 0.036 μm and OS 0.062 μm to OD 0.24 μm and OS 0.22 μm (5 mm pupil diameter) following the time pattern of the equivalent sphere. About 60 days after they had reached their peak, all refraction values and higher-order aberrations stabilized at their baseline levels. The baseline was defined by records taken 4 years before the treatment with insulin was commenced. CONCLUSIONS Wavefront aberrometry gives quantitative insights in the transient alteration and recovering of the eye's optics whilst the therapy of acute type 1 diabetes mellitus is being initiated. The data of this case support the assumption that variations in the crystalline lens, most probably the modification of its refractive gradient index, as a cause for the transient behavior. An explanation is still missing.

PURPOSE To analyze the evolution profiles of several corneal topographic and tomographic parameters in progressive keratoconus and compare them with the kinetics of evolution of anterior keratometry. METHODS One hundred nine eyes of 55 patients were prospectively enrolled and followed up every 3 months for at least 1 year. Forty-five corneal parameters were measured at each visit using a combined Placido-based and dual Scheimpflug imaging system. Percentage of progression between each visit was calculated for each parameter and comparisons were tested between the different variables. RESULTS At 1 year, 11% (12/109) of eyes progressed with an increase in maximum anterior keratometry of 1 D or more. Among these eyes, the posterior maximum keratometry and vertical corneal coma had a significantly higher percentage of progression (P < 0.05) than the maximum anterior keratometry, 5.9%, 27%, and 3.2%, respectively, and occurred significantly earlier than the modifications of the anterior keratometry, at the third-, sixth-, and 12th-month visits, for vertical corneal coma, posterior keratometry, and anterior keratometry respectively. CONCLUSIONS Modifications of the posterior surface and corneal vertical coma occurred earlier and were detectable before changes in the anterior keratometry readings in eyes with progressive keratoconus. These parameters may be relevant warning signs when monitoring progressive keratoconus.

To compare the clinical outcomes of small-incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK (FS-LASIK) for the correction of myopia and myopic astigmatism.In this prospective, randomized, comparative study, SMILE surgery was performed in 113 eyes with a mean spherical equivalent (MSE) of -5.22 ± 1.70 diopters (D) and FS-LASIK was performed in 84 eyes with an MSE of -5.18 ± 1.93 D. Contrast sensitivity and uncorrected and corrected distance visual acuities were measured preoperatively and 1 day, 1 week, 1, 3, and 6 months postoperatively. Higher-order aberrations were evaluated preoperatively and 6 months postoperatively.At postoperative day 1, the uncorrected distance visual acuity in the FS-LASIK group was better (P0.05), whereas no statistically significant difference was found at 6 months postoperatively (P = 0.9). There was no significant difference in terms of logMAR corrected distance visual acuity and MSE during the 6 months of follow-up between the SMILE and FS-LASIK groups (all P0.05). The contrast sensitivity in the SMILE group was lower at 1 day and 1 week postoperatively (all P0.05). The spherical aberration at 6 mm diameter at 6 months postoperatively was lower (P0.05) in the SMILE group (0.12 ± 0.22 μm) than in the FS-LASIK group (0.28 ± 0.26 μm).Both FS-LASIK and SMILE procedures achieved good visual outcomes in the correction of myopia and myopic astigmatism. SMILE had a lower induction rate of spherical aberration at 6 months postoperatively in the analysis of 6 mm diameter than that of FS-LASIK.

To evaluate the changes in corneal higher-order aberrations (HOAs) and their impact on corneal higher-order Strehl ratio after aberration-free ablation profile.Verter Institute, H. Olhos, São Paulo, Brazil.Prospective interventional study.Eyes that had aberration-free myopic ablation were divided into 3 groups, based on the spherical equivalent (SE). The corneal HOAs and higher-order Strehl ratios were calculated before surgery and 3 months after surgery.The postoperative uncorrected-distance visual acuity, corrected-distance visual acuity, and SE did not present statistical differences among groups (88 eyes, P.05). For a 6 mm pupil, the corneal HOA showed a mean increase of 0.17 μm (range 0.39 to 0.56 μm) (P.001) and the corneal higher-order Strehl ratio presented a reduction of 0.03 (from 0.25 to 0.22) (P = .001). The following consistent linear predictive model was obtained: corneal HOA induction = 1.474 - 0.032 × SE - 0.225 × OZ, where OZ is the optical zone (R(2) = 0.49, adjusted R(2) = 0.48, P.001).The corneal HOAs and the higher-order Strehl ratios deteriorated after moderate and high myopic ablations. The worsening in corneal aberrations and optical quality were related to the magnitude of the intended correction and did not affect high-contrast visual performance. The OZ was the only modifiable parameter capable to restrain the optical quality loss.The author has no financial or proprietary interest in any material or method mentioned.

Purpose To propose a new adjustment method and present the clinical result of wavefront-guided myopic laser-assisted in situ keratomileusis (LASIK) retreatment with an aspheric program-targeted central ablation depth to avoid refractive overcorrection. Methods Thirty-two eyes (of 20 consecutive patients) that underwent wavefront-guided LASIK myopic retreatment between January 2009 and February 2012 after primary wavefront-guided LASIK for myopia were included. Wavefront-guided retreatments were performed using the Bausch and Lomb Technolas 217z100 excimer laser system. Wavefront-guided retreatments were adjusted by setting the ablation depth corresponding to the ablation depth determined by the aspheric program. The refractive outcome, visual outcome, and outcome of high-order aberrations (HOAs) were analyzed. Linear mixed models were also used to evaluate the predicting factors for retreatment offset. Results Mean age was 29.5 ± 3.1 years. Spherical equivalent (SE) before retreatment was -1.0 ± 0.44 diopters (D) (range, -2.25 to -0.5). Twelve months postoperatively, SE was -0.03 ± 0.12 D, and 31 of 32 eyes had an uncorrected visual acuity 20/20 or better. All eyes were within ±0.5 D. None of the eyes had lost >2 lines of Snellen visual acuity. Safety and efficacy indices were 1.03 and 1.00, respectively. Total HOA, coma, and trefoil were reduced significantly (P = 0.028, P = 0.036, P = 0.034, respectively). Predictive factors for the amount of offset required are significantly related to preoperative SE (P = 0.006) and spherical aberration (P = 0.03, adjusted by SE). Conclusions Setting the target ablation depth using the aspheric program provided high refractive predictability with a satisfactory visual outcome, significant reduction of HOAs, and no overcorrections.

Purpose: To quantify on-eye rotational and translational stability of three scleral contact lens stabilization methods and to model the variation in visual acuity when these movements occur in a wavefront-guided correction for highly aberrated eyes. Methods: Three lens stabilization methods were integrated into the posterior periphery of a scleral contact lens designed at the Visual Optics Institute. For comparison, a lens with no stabilization method (rotationally symmetric posterior periphery) was designed. The lenses were manufactured and lens movements were quantified on 8 eyes as the average SD of the observed translations and rotations over 60 min of wear. In addition, the predicted changes in acuity for five eyes with keratoconus wearing a simulated wavefront-guided correction (full correction through the fifth order) were modeled using the measured movements. Results: For each lens design, no significant differences in the translation and rotation were found between left and right eyes, and lenses behaved similarly on all subjects. All three designs with peripheral stability modifications exhibited no statistically significant differences in translation and rotation distributions of lens movement and were statistically more stable than the spherical lens in rotation. When the measured movements were used to simulate variation in visual performance, the 3 lenses with integrated stability methods showed a predicted average loss in acuity from the perfectly aligned condition of approximately 0.06 logMAR (3 letters), compared with the loss of over 0.14 logMAR (7 letters) for the lens with the spherical periphery. Conclusion: All three stabilization methods provided superior stability, as compared with the spherical lens design. Simulations of the optical and visual performance suggest that all three stabilization designs can provide desirable results when used in the delivery of a wavefront-guided correction for a highly aberrated eye.

An understanding of corneal optics is important to optimize the visual outcome after eye surgery. Recent advances in the surgical techniques of lamellar keratoplasty have changed the strategies used for corneal transplantation. Lamellar keratoplasty has the advantage of having a lower rate of graft rejection, superior biomechanical properties, and reduced higher-order aberrations (HOAs) compared with penetrating keratoplasty; thus, the use of lamellar keratoplasty has increased over the last 15 years. However, some patients have poor postoperative visual acuity despite a clear cornea, and the reasons for the poor visual outcome are poorly understood. By combining corneal imaging technologies and the latest optical software, we proposed the concept of "parallelism of anterior and posterior surfaces in lamellar keratoplasty." In physiologically normal eyes, in which the anterior and posterior surfaces are parallel to each other, the posterior surface of the cornea compensates the HOAs of the anterior surface, and this is also true in eyes after penetrating keratoplasty. However, after lamellar keratoplasty, in which the anterior and posterior surfaces are independent and not parallel, irregularities in the posterior surface increase the HOAs of the anterior surface. This article introduces this concept to enhance our understanding of visual optics in eyes after penetrating and lamellar keratoplasties and how to apply this concept to surgery to improve and optimize patient visual outcomes.

PURPOSE To evaluate the difference in corneal biomechanical waveform parameters between manifest keratoconus, forme fruste keratoconus, and healthy eyes with a second-generation biomechanical waveform analyzer (Ocular Response Analyzer 2). SETTING Jules Stein Eye Institute, University of California, Los Angeles, California, USA. DESIGN Retrospective chart review. METHODS The biomechanical waveform analyzer was used to obtain corneal hysteresis (CH), corneal resistance factor (CRF), and 37 biomechanical waveform parameters in manifest keratoconus eyes, forme fruste keratoconus eyes, and healthy eyes. Useful distinguishing parameters were found using t tests and a multivariable logistic regression model with stepwise variable selection. Potential confounders were controlled for. RESULTS The study included 68 manifest keratoconus eyes, 64 forme fruste keratoconus eyes, and 249 healthy eyes. There was a statistical difference in the mean CRF between the normal group (10.2 mm Hg ± 1.7 [SD]) and keratoconus group (6.3 ± 1.9 mm Hg) (P = .003), and between the normal group and the forme fruste keratoconus group (7.8 ± 1.4 mm Hg) (P < .0001). There was no statistical difference in the mean CH between the normal group and the keratoconus group or the forme fruste keratoconus group. The CRF, height of peak 1 (P1) (P = .001), downslope of P1 (dslope1) (P = .027), upslope of peak 2 (P2) (P = .004), and downslope of P2 (P = .006) distinguished the normal group from the keratoconus groups. The CRF, downslope of P2 derived from upper 50% of applanation peak (P = .035), dslope1 (P = .014), and upslope of P1 (P = .008) distinguished the normal group from the forme fruste keratoconus group. CONCLUSION Differences in multiple biomechanical waveform parameters can differentiate between healthy and diseased conditions and might improve early diagnosis of keratoconus and forme fruste keratoconus. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.