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Purpose: To present the outcomes and detail the surgical procedure employed in the initial 102 eyes treated with keratorefractive lenticule extraction (KLEx) using the FEMTO LDV Z8 platform (Ziemer Ophthalmic Systems)., Methods: This was a retrospective analysis of 102 eyes of 53 patients treated with KLEx at the American University of Beirut Medical Center. Visual, refractive, topographic, and aberrometric parameters were evaluated 1 week and 1, 3, 6, and 12 months postoperatively., Results: Mean preoperative spherical equivalent refraction (SEQ) was -4.11 ± 1.82 diopters (D) (range: -10.00 to -1.625 D) and mean preoperative cylinder was -0.75 ± 0.65 D (range: -3.00 to 0.00 D). Postoperatively, the mean SEQ was 0.06 ± 0.54 D (range: -2.88 to +1.00 D) at 1 week and -0.04 ± 0.26 D at 12 months and was within ±0.50 D in 95.6% and ±1.00 D in 100% of eyes. A total of 96.7% of eyes had an uncorrected distance visual acuity (UDVA) of 20/20 at 12 months postoperatively. Fifty percent gained one or more lines of corrected distance visual acuity (CDVA), 5 eyes (5.4%) lost one line, and none lost two or more lines. No suction losses were encountered and all extracted lenticules were intact without tears., Conclusions: The application of KLEx using the FEMTO LDV Z8 platform yields safe and effective outcomes, aligning comparably with established modes of lenticule extraction and femtosecond laser-assisted laser in situ keratomileusis procedures previously employed and accepted within the field of refractive surgery. [ J Refract Surg . 2024;40(11):e898-e905.] ., Competing Interests: Disclosure: STA is a consultant for Ziemer Ophthalmic Systems AG. The remaining authors have no disclosed no potential conflicts of interest, financial or otherwise.

Purpose: To compare and assess the visual, refractive, and tomographic results of patients with corneal ectasia treated with either corneal allogenic intrastromal ring segments (CAIRS) or synthetic intrastromal corneal ring segments (ICRS) without concomitant corneal cross-linking., Methods: In this retrospective cohort study, 34 eyes with CAIRS were matched to 34 eyes with ICRS using the propensity score matching technique. Each group was matched on a oneto-one basis using multiple parameters such as central corneal thickness, vertical and horizontal coma, maximum anterior keratometry, steepest keratometry, and age. Visual, refractive, topographic, and aberrometric data were measured at baseline, 1 week, 1 month, 3 months, and 1 year postoperatively., Results: Initial preoperative parameters were similar between the two groups. Both groups showed significant improvement at last follow-up time in corrected distance visual acuity (CDVA) (0.52 ± 0.23 to 0.16 ± 0.18 logarithm of the minimum angle of resolution [logMAR], P < .001; 0.44 ± 0.27 to 0.17 ± 0.21 logMAR, P < .001), topographic astigmatism (4.45 ± 2.75 to 3.14 ± 1.93 diopters [D], P = .001; 3.66 ± 2.22 to 2.36 ± 1.46 D, P = .007), maximum anterior keratometry (55.85 ± 7.53 to 50.69 ± 6.38 D, P < .001; 54.59 ± 6.95 to 50.71 ± 4.51 D, P = .003), and vertical coma (1.49 ± 1.02 to 0.38 ± 0.65 D, P < .001; 1.22 ± 0.75 to 0.52 ± 0.57 D, P < .001) for CAIRS and ICRS, respectively. The improvements observed in both groups at the last follow-up visit were comparable; however, the CAIRS group demonstrated a higher percentage of eyes gaining two or more Snellen lines of CDVA (60% vs 31.58%, P = .04), and a greater magnitude of reduction in vertical coma compared to the ICRS group, although this difference did not reach statistical significance. No major complications were observed with both groups, and one eye lost one CDVA line in the ICRS group. The mean thickness of the CAIRS segments at the last follow-up visit was 401.06 ± 100.12 µm, compared to 435.29 ± 26.19 µm for ICRS. Both CAIRS and ICRS demonstrated significant compression of stromal thickness above the segment (36.19% and 32.00%, respectively)., Conclusions: When adequately matched for preoperative disease type and severity, eyes with CAIRS had a similar and notable clinical improvement compared to ICRS, with possibly better improvement in vertical coma and CDVA. [ J Refract Surg . 2024;40(11):e863-e876.] ., Competing Interests: Disclosure: SJ has a patent pending for special trephines, devices, and processes used to create these segments, as well as for the corneal allogenic intrastromal ring segments and various types of shaped corneal segments. The remaining authors have reported no potential conflicts of interest, financial or otherwise.

Purpose: To compare haze and refractive outcomes in patients undergoing combined accelerated corneal cross-linking (A-CXL) and selective wavefront-guided transepithelial photorefractive keratectomy (WG-transPRK) without mitomycin C (MMC) versus those undergoing A-CXL., Methods: This prospective study analyzed 95 eyes (86 patients) with progressive keratoconus from October 2018 to October 2022. The first group underwent CXL combined with corneal or ocular WG-transPRK (CXL+PRK, n = 52), targeting higher order aberrations (HOAs). The second underwent CXL only (n = 43), both following the same accelerated CXL protocol without MMC on the SCHWIND Amaris laser platform (SCHWIND eye-tech-solutions). Baseline and postoperative evaluations (1, 3, 6, and 12 months) included uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refraction, tomography, corneal HOAs, and optical coherence tomography (OCT) scans. A patented machine learning algorithm objectively detected and quantified stromal haze on OCT scans in grayscale units., Results: In both groups, anterior corneal haze reflectivity and subepithelial haze peaked at 3 months postoperatively, then progressively decreased at 6 and 12 months. Haze did not differ between groups at any time point. By 12 months, CDVA increased by 2.5 lines in the CXL+PRK group ( P < .001) and by 0.7 lines in the CXL group ( P = .10), and maximum keratometry decreased from 51.70 ± 5.10 to 47.90 ± 7.90 diopters (D) (CXL+PRK group) ( P < .001) and from 51.20 ± 5.10 to 50.30 ± 4.60 D (CXL group) ( P = .004). Corneal HOAs decreased in both groups but more in the CXL+PRK group., Conclusions: Combining CXL with WG-transPRK without MMC does not result in increased haze when compared to A-CXL alone. This combined approach achieves greater improvements in visual, topographic, and aberrometric parameters. [ J Refract Surg . 2024;40(9):e583-e594.] .

Purpose: To investigate the efficacy of incorporating Generative Adversarial Network (GAN) and synthetic images in enhancing the performance of a convolutional neural network (CNN) for automated estimation of Implantable Collamer Lens (ICL) vault using anterior segment optical coherence tomography (AS-OCT)., Methods: This study was a retrospective evaluation using synthetic data and real patient images in a deep learning framework. Synthetic ICL AS-OCT scans were generated using GANs and a secondary image editing algorithm, creating approximately 100,000 synthetic images. These were used alongside real patient scans to train a CNN for estimating ICL vault distance. The model's performance was evaluated using statistical metrics such as mean absolute percentage error (MAPE), mean absolute error (MAE), root mean squared error (RMSE), and coefficient of determination ( R 2 ) for the estimation of ICL vault distance., Results: The study analyzed 4,557 AS-OCT B-scans from 138 eyes of 103 patients for training. An independent, retrospectively collected dataset of 2,454 AS-OCT images from 88 eyes of 56 patients, used prospectively for evaluation, served as the test set. When trained solely on real images, the CNN achieved a MAPE of 15.31%, MAE of 44.68 µm, and RMSE of 63.3 µm. However, with the inclusion of GAN-generated and algorithmically edited synthetic images, the performance significantly improved, achieving a MAPE of 8.09%, MAE of 24.83 µm, and RMSE of 32.26 µm. The R 2 value was +0.98, indicating a strong positive correlation between actual and predicted ICL vault distances ( P < .01). No statistically significant difference was observed between measured and predicted vault values ( P = .58)., Conclusions: The integration of GAN-generated and edited synthetic images substantially enhanced ICL vault estimation, demonstrating the efficacy of GANs and synthetic data in enhancing OCT image analysis accuracy. This model not only shows potential for assisting postoperative ICL evaluations, but also for improving OCT automation when data paucity is an issue. [ J Refract Surg . 2024;40(4):e199-e207.] .

Purpose: To describe a novel technique for cutting asymmetric allogenic segments using the femtosecond laser for the management of cases of keratoconus with non-coinciding astigmatism and coma axes., Methods: Four eyes of 2 patients with irregular keratoconus and asymmetric allogenic segments were included. Visual, refractive, tomographic, and aberrometric outcomes, and optical coherence tomography (OCT) sections were measured preoperatively and 6 months postoperatively. Evaluations included slit-lamp examination, manifest refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuity, and simulated and maximum anterior keratometry (Kmax) using anterior segment OCT., Results: Spherical and cylindrical refractive errors decreased from -2.38 ± 2.96 and -2.94 ± 2.16 to -1.81 ± 2.77 ( P = .04) and -1.75 ± 2.07 ( P = .01) diopters (D), respectively, 6 months postoperatively. There was an average gain of three lines of CDVA. Kmax decreased from 50.02 ± 1.99 to 47.89 ± 3.05 D (P= .03) and coma from 1.05 ± 0.21 to 0.21 ± 0.19 D ( P = .01)., Conclusions: Asymmetric femtosecond laser-cut allogenic segments allow a higher level of customization based on size, shape, and arc length, in contrast to the limited range of available synthetic asymmetrical segments. [ J Refract Surg . 2023;39(12):856-862.] .

Purpose: To evaluate the visual, refractive, and tomographic results of patients with corneal ectasia treated with corneal allogenic intrastromal ring segments (CAIRS) insertion without concomitant corneal cross-linking., Methods: Fifty-two eyes from 39 patients with stable corneal ectasia and unsatisfactory visual acuity with contact lenses were included. All patients underwent CAIRS insertion with no concomitant corneal procedure at the American University of Beirut Medical Center between September 2019 and July 2022. Visual, refractive, topographic, aberrometric, epithelial, stromal, and segment thickness data were measured relative to baseline at 1 week, 1 month, and at least 3 months postoperatively. Evaluations included slit-lamp examination, manifest refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuity, and tomography using anterior segment optical coherence tomography., Results: Mean follow-up time was 6.9 ± 5.2 months. UDVA and CDVA improved from 0.97 ± 0.47 and 0.56 ± 0.19 preoperatively to 0.52 ± 0.21 ( P < .001) and 0.23 ± 0.19 ( P < .001) 3 months postoperatively. Manifest refraction spherical equivalent and cylinder improved from -6.71 ± 6.51 and -4.02 ± 2.24 diopters (D) preoperatively to -3.78 ± 4.07 D ( P < .001) and -2.35 ± 1.98 D ( P < .001) 3 months postoperatively, respectively. Maximum anterior keratometry and vertical coma decreased from 58.09 ± 7.92 D and 1.56 ± 1.09 µm to 52.48 ± 6.69 D ( P < .001) and 0.43 ± 0.77 µm, respectively ( P < .001). Corneal epithelium thickened proximal to the allogenic segment by 7.25 µm ( P < .001), whereas stromal elevation at the cone decreased from 38.61 ± 18.5 to 23.82 ± 13.4 µm, respectively ( P < .001). No major complications were observed and only 1 eye lost one line of CDVA., Conclusions: Treatment of corneal ectasia with CAIRS improved visual, refractive, topographic, and tomographic parameters. Epithelial thickening central to CAIRS, along with anterior stromal flattening is postulated to contribute to tomographic flattening and regularization. [ J Refract Surg . 2023;39(11):767-776.] .

Purpose: To determine the effectiveness of parameters and indices based on biomechanical measures at discriminating fellow eyes with topographically and tomographically normal corneas in patients with keratoconus from normal control corneas., Methods: The study included 47 keratoconus suspect eyes, defined as the topographically and tomographically normal fellow eyes of patients with frank keratoconus in the other eye. Eyes were imaged using the Pentacam HR and Corvis ST (both Oculus Optikgeräte GmbH). Fellow eyes were then categorized as topographically/tomographically normal fellow eyes (TNF) and topographically/tomographically borderline fellow eyes (TBF). The ability of each of the Corvis Biomechanical Index (CBI), Tomographic and Biomechanical Index (TBI), stiffness parameter at applanation 1 (SP-A1), and stress-strain index (SSI) at discriminating between normal controls and keratoconus suspects was assessed., Results: The TBI had the best discriminative ability with the greatest area under the receiver operating characteristic (AUROC) curve value of 0.946 for normal controls versus TBF eyes, and 0.824 for normal controls versus TNF eyes. Compared to the TBI AUROC curves, SP-A1 and CBI had AUROC curve values of 0.833 ( P = .09) and 0.822 ( P = .01) for normal controls versus TBF eyes, respectively, and AUROC curve values of 0.822 ( P = .96) and 0.550 ( P = .0002) for normal controls versus TNF eyes, respectively. The TBI had the best positive predictive value for TNF and TBF eyes, followed by CBI and SP-A1., Conclusions: The TBI and the purely biomechanical parameter SP-A1 were of moderate utility in distinguishing between normal and keratoconus suspect eyes. In the absence of topographic/tomographic evidence of keratectasia, an independently abnormal biomechanical parameter may suggest an increased risk of ectasia. [ J Refract Surg . 2022;38(5):318-325.] .

Purpose: To evaluate management of keratoconic eyes with anterior stromal necrosis overlying the intracorneal ring segment (ICRS), by either ICRS explantation alone or exchange with corneal allogenic intrastromal ring segments (CAIRS)., Methods: Among 643 Intacs SK (Additional Technology, Inc) inserted at one institutional center, 16 eyes (15 patients) with overlying spontaneous anterior stromal necrosis were identified. Data included size of stromal defect and refractive and topographical findings before ICRS insertion, before anterior stromal necrosis, and 6 months after intervention., Results: The 10-year incidence of anterior stromal necrosis after femtosecond laser-assisted ICRS insertion was 5.5%. Eight eyes underwent ICRS removal only and 8 eyes had ICRS exchanged with CAIRS. In the first group, CDVA worsened from 0.14 before melt to 0.28 logMAR after removal ( P = .10), simulated keratometry (SimK) and maximum axial keratometry (Kmax) increased from 44.73 to 46.34 diopters (D) ( P = .14) and from 49.23 to 52.26 D ( P = .14), respectively, and coma worsened from 0.87 to 1.52 D ( P = .02). In the CAIRS group, CDVA of 0.16 before melt improved to 0.11 logMAR postoperatively ( P > .99), and topographic indices stabilized with SimK, Kmax, and coma mildly altering from 45.31 to 45.44 D ( P > .99), from 49.25 to 49.64 D ( P > .99) and from 0.87 to 0.81 D ( P > .99), respectively. Whether the ICRS were explanted or exchanged, the visual and topographic mean values were better than those reported before ICRS implantation, whereas higher order aberrations in eyes without CAIRS regressed to levels before ICRS insertion. At the site of melt, thinnest residual stromal thickness averaged 327 µm with ICRS removal and 490 µm with CAIRS. Eyes with larger melt areas resulted in less optimal results with CAIRS implantation., Conclusions: Early experience in the management of anterior stromal necrosis by exchange of polymethylmethacrylate ICRS with CAIRS seems to avoid stromal thinning and confer better visual and topographic results, which were more pronounced with thicker segments. The benefit of CAIRS in large stromal melts needs to be investigated. [ J Refract Surg . 2022;38(4):256-263.] .

Purpose: To evaluate and compare corneal haze as determined by optical coherence tomography (OCT) after corneal cross-linking (CXL) for the treatment of mild to moderate keratoconus with or without mitomycin C (MMC) application., Methods: This was a retrospective analysis of 87 eyes of 72 patients with mild to moderate keratoconus. The first group (n = 44 eyes) underwent CXL between June 2013 and January 2015 and the second group (n = 43 eyes) underwent CXL with MMC (CXL+MMC) between February and December 2015, both following the Dresden protocol. Patients were evaluated preoperatively and at 1, 3, 6, and 12 months postoperatively. Main outcome measures were corneal reflectivity and haze reflectivity measured by a specially developed OCT image analysis software., Results: Anterior corneal reflectivity at 1 month and 1 year postoperatively was 14.79 ± 4.68 and 25.97 ± 15.01 (P < .001), and 13.88 ± 4.39 and 18.41 ± 9.25 (P = .025) for the CXL and CXL+MMC groups, respectively. The reflectivity of the anterior stromal haze region at 1 month and 1 year postoperatively was 23.15 ± 5.91 and 33.14 ± 16.58 (P = .005), and 20.58 ± 7.88 and 27.14 ± 12.80 (P = .049) for both groups, respectively. The changes in simulated keratometry from preoperatively to postoperatively were similar in both groups. The CXL+MMC group showed larger maximum keratometry flattening: 53.41 ± 6.88 diopters (D) preoperatively and 49.44 ± 5.66 D 1 year postoperatively versus 52.27 ± 5.78 and 50.91 ± 4.25 D for CXL alone (P = .008)., Conclusions: MMC application following CXL significantly increases corneal haze. Similar studies need to be performed on simultaneous CXL and photorefractive keratectomy to evaluate the role of MMC in haze formation in such procedures. [J Refract Surg. 2021;37(2):83-90.]., (Copyright 2021, SLACK Incorporated.)

Purpose: To evaluate the efficacy of simultaneous laser in situ keratomileusis (LASIK) and small-aperture corneal inlay (KAMRA; AcuFocus, Inc) implantation in hyperopic presbyopic eyes at 5 years postoperatively., Methods: This was a retrospective single-center study of patients with hyperopia and presbyopia who underwent simultaneous LASIK and corneal inlay implantation by two experienced refractive surgeons. These patients were regularly observed for 5 years and evaluated with serial corneal tomographies and refractive assessments for uncorrected near visual acuity (UNVA), uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), distance-corrected near visual acuity (DCNVA), and manifest refraction spherical equivalent (MRSE)., Results: Twenty-four eyes of 24 patients were included. Mean age was 53.63 ± 4.11 years (range: 47 to 63 years) and mean preoperative MRSE was +1.52 ± 0.64 diopters (D) (range: +0.50 to +3.00 D). UNVA was 0.04 ± 0.06 logMAR at 1 month and 0.02 ± 0.05 logMAR (J1+ equivalent) at 5 years postoperatively. In comparison, preoperative DCNVA was 0.44 ± 0.20 (J5/J6 equivalent) (P < .001). At 5 years postoperatively, UDVA was 0.16 ± 0.18 logMAR (20/30 Snellen equivalent), and 23 of 24 eyes (95.8%) had UNVA of J3 or better. Two eyes (8.3%) lost one line of CDVA. One corneal inlay needed readjustment but none were explanted. Eight eyes (25%) developed regression in UNVA with hyperopic shift, which responded to a 3- to 4-month course of topical steroids, with 3 eyes showing patchy haze on the undersurface of the corneal inlay., Conclusions: Simultaneous LASIK and KAMRA inlay implantation, evaluated for 5 years postoperatively, shows some efficacy and predictability in improving UDVA and UNVA in hyperopic presbyopic eyes. However, late-onset regression with hyperopic shift, possible loss of CDVA, and occasional haze remain challenges. [J Refract Surg. 2020;36(8):498-505.]., (Copyright 2020, SLACK Incorporated.)

Purpose: To introduce a customized ablation area photo-therapeutic keratectomy (PTK) technique that uses a preoperatively generated laser ablation profile to accurately match and ablate the area of the pathology., Methods: A case of mid-peripheral Salzmann's nodular degeneration causing recurrent epithelial erosion is described. The white-to-white distance, on a slit-lamp image of the patient's eye, was measured by a Placido and dual-Scheimpflug analyzer and used as a scale on a Java-based image processing program to extrapolate the focal corneal pathology's vertical and horizontal dimensions on the corneal plane. The lesion's depth was measured by corneal optical coherence tomography (OCT). Customized ablation area transepithelial PTK, tailored to the exact dimensions of the pathology was then performed in one pass, regionally ablating the area of the pathology only., Results: Complete epithelial healing was observed by the next day with unaltered visual acuity of 20/20. Corneal OCT performed at 1 and 3 months postoperatively showed near-complete resolution of the lesion. The patient was followed up for a total of 6 months with no reported symptoms of corneal erosions., Conclusions: The application of a customized laser ablation area in the treatment of Salzmann's nodular degeneration and other focal stromal pathologies avoids unnecessary epithelial and stromal ablation. This contributes to faster visual recovery and less refractive impact, especially for peripheral lesions. [J Refract Surg. 2020;36(5):340-344.]., (Copyright 2020, SLACK Incorporated.)

Purpose: To analyze the implications of different reference points on the read-out of epithelial thickness mapping., Methods: A simulation for changing the reference point from normal-to-the-surface tangent to parallel vertical sections quantifying its effect on the read-out of epithelial thickness mapping has been developed. The simulation includes a simple modeling of corneal epithelial profiles and allows the analytical quantification of the differences in the read-out from normal-to-the-surface tangent to parallel vertical sections epithelial thickness mapping., Results: The difference in the read-out between parallel vertical sections and normal-to-the-surface tangent epithelial thickness mapping increases for steeper corneas, but it is not largely affected by asphericity. The difference increases for thicker epithelia., Conclusions: The reference point for determining the readout of epithelial thickness mapping should be taken into account when interpreting output. Using conventional epithelial thickness map readings (normal-to-the surface tangent) in transepithelial ablations (representing close to parallel vertical sections) may result in induced refractive errors that can be quantified using simple theoretical simulations, because the center-to-periphery progression of the corneal epithelial profile deviates from the progression of the ablated one. Adjustments for the epithelial thickness read-out or, alternatively, for the target sphere can be easily derived. [J Refract Surg. 2020;36(2):200-207.]., (Copyright 2020, SLACK Incorporated.)

Purpose: To assess the efficacy and safety of early one-step transepithelial photorefractive keratectomy (PRK) with mitomycin C as treatment for buttonhole formation during LASIK., Methods: Eight patients who developed a buttonhole during LASIK with mechanical or femtosecond flap creation underwent one-step transepithelial PRK a few days after the formation of the buttonhole. The re-treatment procedure was performed after complete epithelial healing and smooth epithelial fluorescein profile were ensured. Postoperative manifest refraction, uncorrected and corrected distance visual acuity, and haze formation were assessed during 6 months of follow-up., Results: Mean duration of the re-treatment procedure after buttonhole formation was 5 days (range: 4 to 7 days). Mean manifest refractive spherical equivalent and cylinder refraction were -0.05 ± 0.18 and -0.18 ± 0.22 diopters, respectively, at 6 months postoperatively. Uncorrected distance visual acuity was 20/20 in all patients after 3 months of follow-up. No haze formation was detected., Conclusions: Early one-step transepithelial PRK with mitomycin C seems to be a safe and effective treatment for LASIK buttonhole complication., (Copyright 2015, SLACK Incorporated.)

Purpose: To report clinical results and safety profiles of symmetrical intrastromal corneal ring segment (ICRS; Intacs SK, Addition Technology Inc) implantation in eyes with moderate to severe keratoconus., Methods: Interventional case series of 24 eyes from 22 patients implanted with Intacs SK using the femtosecond laser. Evaluation included uncorrected (UDVA) and corrected distance visual acuity (CDVA), manifest refraction, and Placido-based Scheimpflug imaging. Postoperative follow-up was 1 day, 1 week, and 1, 3, and 6 months., Results: Mean patient age was 28±7 years (range: 16 to 41 years). All eyes had keratoconus. Twenty-one of 24 eyes had 2, 450-μm symmetrical segments inserted. Mean UDVA and CDVA were significantly better at 1, 3, and 6 months postoperatively (UDVA: 20/340 preoperatively vs 20/70 at 6 months [P<.001]; CDVA: 20/70 preoperatively vs 20/40 at 6 months [P<.001]; UDVA analysis of variance [ANOVA]: F=6.46, P=.0057; CDVA ANOVA: F=5.24, P=.0138). Pre- and 6-months postoperative clinical results were: mean spherical equivalent refractive error -9.60±4.86 diopters (D) and -3.05±2.05 D (P<.001), respectively; mean refractive cylinder, -3.20±1.50 D and -1.55±1.10 D, respectively (P<.001); and mean average total corneal power 52.03±4.49 D and 46.95±4.61 D, respectively (P<.001). No complications occurred, and no patients were lost to follow-up. Eyes with steeper preoperative corneal keratometry readings had the greatest flattening in corneal curvature and thus the greatest decrease in myopic refraction (r=-0.4, P<.001). No correlation was found between preoperative thinnest corneal pachymetry and postoperative curvature flattening., Conclusions: Implantation of Intacs SK for moderate to severe keratoconus is safe and effective, leading to significant decrease in myopia and appreciable decrease in astigmatism with improvement in CDVA., (Copyright 2012, SLACK Incorporated.)

Purpose: To evaluate agreements in lower and higher order aberration measurements by two Hartmann-Shack wavefront-sensing devices., Methods: Using the VISX WaveScan and Alcon LADARWave aberrometers, ocular aberrations at a fixed optical zone of 6 mm were measured on 36 eyes of 18 patients. A tunable light intensity source was used to control pupil size, which was checked using infrared pupillometry. Repeatability of measurements was evaluated using the intra-class correlation coefficient with 3 consecutive measurements on each aberrometer., Results: Mean absolute defocus for WaveScan and LADARWave was 2.82 +/- 2.69 and 2.93 +/- 3.24 root-mean-square (RMS) microm, whereas astigmatism was 0.81 +/- 0.49 and 0.87 +/- 0.57 microm, respectively. Pearson correlation coefficients between the two aberrometers were 0.908 and 0.870 for defocus and astigmatism, respectively, whereas higher order aberration correlation was less tight (Pearson correlation coefficient=0.596 for coma, 0.746 for trefoil, 0.836 for spherical aberration, 0.637 for secondary astigmatism, and 0.963 for quadra-foil [P<.001 for all]). The LADARWave had a tendency to display more spherical aberration than the WaveScan, especially at high aberration values, with mean absolute difference in measurement of 0.12 +/- 0.08 microm, and only 44% of eyes having less than +/-0.10 RMS microm of difference. The mean total higher order aberration absolute difference was 0.14 +/- 0.14 microm, with only 50% of eyes within +/-0.1 RMS of agreement. Vector analysis revealed appreciable discrepancies in third- and fourth-order directional Zemike components, while showing similar values for fifth-order components. Intra-class correlation coefficient values for both aberrometers over different aberration orders showed excellent repeatability., Conclusions: The WaveScan and LADARWave share similar lower order aberration measurements, but display significantly different higher order aberration values.

Purpose: To evaluate the objective and subjective visual outcomes and refractive results of wavefront-guided LASIK with LADAR CustomCornea and VISX CustomVue., Methods: This prospective randomized single-institution multisurgeon study comprised 100 eyes of 58 patients (50 eyes on each laser platform). Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and manifest refraction were measured postoperatively at 1 day, 1 week, 1 month, and 3 months. Contrast sensitivity, higher order aberrations measurement, and a subjective vision questionnaire were performed preoperatively and at 3 months., Results: Preoperatively, the CustomCornea group had a mean manifest sphere of -3.58 +/- 1.61 diopters (D) (range: -0.50 to -7.25 D), cylinder of +0.64 +/- 0.45 D (range: 0 to +1.75 D), and manifest refractive spherical equivalent (MRSE) of -3.26 +/- 1.56 D. The CustomVue group had a manifest sphere of -4.00 +/- 1.69 D (range: -1.50 to -7.50 D), cylinder of +0.60 +/- 0.52 D (range: 0 to +2.00 D), and MRSE of -3.70 +/- 1.64 D. At 3 months, 94% of CustomCornea eyes and 84% of CustomVue eyes had UCVA > or = 20/20 (P = .20). Twenty-four percent of CustomVue eyes and 22% of CustomCornea eyes gained 1 line of BSCVA. In both groups, 96% of eyes were within 0.50 D of emmetropia. Mean CustomCornea glare contrast sensitivity improved (P = .04) whereas more eyes improved than worsened in both groups. Spherical aberration and total higher order aberrations increased, and trefoil decreased in both groups. A decrease in coma was noted in 70% of CustomCornea eyes., Conclusions: Wavefront-guided LASIK with both platforms is safe, effective, and delivers excellent visual results. CustomCornea improves contrast sensitivity under glare conditions.

Purpose: To evaluate and compare the surgically induced astigmatism in myopic eyes undergoing conventional and wavefront-guided LASIK., Methods: A retrospective review was performed of the charts of 200 myopic eyes of 121 patients who underwent either custom or conventional treatments via the VISX S4 or LADARVision4000 platforms (50 consecutive eyes in each of the four groups). The primary outcome measure was manifest refraction, which was evaluated preoperatively and at 3 months postoperatively. The magnitude and axis of the unintended surgically induced astigmatism were calculated using vector analysis. The Student t test was used to compare the magnitudes of the surgically induced astigmatism and the absolute angle of error., Results: The mean preoperative manifest cylinder was 0.66 +/- 0.38 diopters (D) for conventional VISX S4 and 0.68 +/- 0.39 D for VISX CustomVue (P = .795), and 0.76 +/- 0.56 D for LADARVision and 0.61 +/- 0.36 D for LADAR CustomCornea (P = .114). The success index was 0.19 +/- 0.41 for VISX S4 and 0.49 +/- 0.49 for VISX CustomVue (P = .0013), and 0.25 +/- 0.47 for LADARVision and 0.20 +/- 0.39 for LADAR CustomCornea (P = .5721). The absolute mean angle of error was 4.4 +/- 13.9 degrees for VISX S4 versus 14.9 +/- 23.9 degrees for VISX CustomVue (P = .0085), and 6.1 +/- 12.30 for LADARVision versus 3.9 +/- 11.1 degrees for LADAR CustomCornea (P = .3501). Of the VISX CustomVue eyes, 32% had an absolute angle of error > 10 degrees, as compared to 10% for both the VISX S4 and LADAR CustomCornea eyes (P = .013), and 16% for the LADARVision group (P = .056)., Conclusions: Wavefront-guided ablation is associated with higher surgically induced astigmatism and larger astigmatic axis shift on the VISX platform as compared to the LADAR CustomCornea and the LADAR and VISX conventional platforms. Care should be emphasized mainly during registration/alignment to minimize surgically induced astigmatism in wavefront-guided LASIK.

Purpose: To evaluate and compare the visual and clinical outcomes of wavefront-guided laser in situ keratomileusis (LASIK) with the Alcon CustomCornea (Alcon Laboratories Inc, Fort Worth, Tex) and VISX CustomVue (VISX, Santa Clara, Calif) systems., Methods: Ninety-three eyes of 56 patients (50 and 43 consecutive eyes on CustomCornea and CustomVue, respectively) were enrolled in a prospective multisurgeon clinical outcome study. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and manifest refraction were measured at 1 day, 1 week, 1 month, and 3 months postoperatively. Early treatment diabetic retinopathy study (ETDRS) visual acuity and contrast sensitivity were measured at 1 month and 3 months, and wavefront mapping at 3 months., Results: Preoperatively, the CustomCornea group had a mean sphere of -3.90 +/- 1.62 diopters (D) (range -0.50 to -7.25 D), mean cylinder of +0.62 +/- 0.39 D (range 0 to +1.50 D), and mean manifest spherical equivalent refraction of -3.59 +/- 1.54 D. The CustomVue group had a sphere of -3.87 +/- 1.45 D (range -1.75 to -6.75 D), cylinder of +0.49 +/- 0.36 D (range 0 to +1.50 D), and manifest spherical equivalent refraction of -3.62 +/- 1.46 D. At 3 months, 98% of the CustomCornea group and 95% of the CustomVue group were within +/-0.50 D. Ninety-nine percent of eyes did not change >0.50 D (manifest spherical equivalent refraction) between 1 month and 3 months. CustomCornea eyes improved on contrast sensitivity testing and had a better profile than CustomVue for 20/15 Snellen and 20/12.5 ETDRS acuity. Both laser groups had a decrease in higher order aberrations with statistical significance for coma and spherical aberration in the CustomCornea group., Conclusion: Wavefront-guided LASIK with both systems is safe and effective.