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Purpose: To determine glare-induced change during visual acuity testing in patients with and without cataract using the controlled point source light-emitting diode (LED) glare tester (EpiGlare Tester; Epico, LLC, Columbus, OH), a new medical device for identification of glare disability., Methods: This prospective, multicenter study enrolled 40 patients (80 eyes with cataracts) and 49 control subjects (98 eyes without cataracts). Corrected distance visual acuity (CDVA) was measured with and without glare using the EpiGlare Tester as a glare source. Functional visual ability was evaluated using driving and glare subscales from the Refractive Status Vision Profile questionnaire. The primary efficacy measure was change in CDVA measurement with and without glare in patients with senile cataract compared to participants without cataract. Secondary efficacy measures included correlation of the CDVA change caused by functional glare disability and subjective patient and investigator assessments., Results: CDVA reduction was greater for patients with cataract, with a mean reduction of -0.49 ± 0.3 logMAR, than for participants without cataracts at -0.13 ± 0.2 logMAR (P < .001). This equates to a 5-line Snellen reduction (0.49 logMAR) in patients with cataracts and a 1-line reduction (-0.13 logMAR) in patients without cataracts. Among patients with cataracts, 83% stated the device accurately represented the difficulty experienced while driving at night (P < .001); among participants without cataracts, 71% reported being minimally affected by glare from the device (P = .003)., Conclusions: A new controlled point source LED glare tester demonstrated the adverse effect on visual acuity due to glare in patients with cataract, accurately simulated night driving glare issues for patients with cataracts, and was rated as easy to use and useful by investigators., (Copyright 2015, SLACK Incorporated.)

Purpose: To compare surgically induced astigmatism (SIA) based on incision site and evaluate the clinical results and astigmatic stability of iris-claw phakic intraocular lens (Artisan lens; Ophtec BV, Groningen, Netherlands) implantation., Methods: Eighty-five eyes of 53 patients with myopia who underwent Artisan lens implantation with a 6.2-mm incision and follow-up of 6 months were retrospectively observed. SIA was assessed using keratometric astigmatism at 6 months postoperatively for the incision sites of the sclera, limbus, and cornea, and the efficacy, safety, predictability, and astigmatic stability were also calculated., Results: SIA obtained using Naeser's polar method (KP[90]SIA) was -0.48 ± 0.35 for scleral incisions, -0.99 ± 0.35 for limbal incisions, and -1.14 ± 0.54 for corneal incisions. Corresponding net astigmatism values, as calculated with KP(90)SIA and KP(135)SIA, were 0.70 ± 0.48 (177°), 1.04 ± 0.37 (175°), and 1.21 ± 0.57 (1°), respectively, with SIA increasing the nearer the incision was to the cornea center. Six months after surgery, the efficacy index was 1.03 and the safety index was 1.08. Ninety-eight percent of patients were within 1.50 diopters of attempted refraction., Conclusions: The values of SIA after Artisan lens insertion showed significant differences among three incision locations, despite the absence of significant differences in preoperative steep corneal axis astigmatism values at the incision locations. It would be applicable for refractive surgery in the aspect of minimizing astigmatism after surgery., (Copyright 2014, SLACK Incorporated.)

Purpose: To evaluate changes in corneal epithelial and stromal thickness after corneal collagen cross-linking (CXL) in eyes with keratoconus and postoperative corneal ectasia using spectral-domain optical coherence tomography (SD-OCT)., Methods: Anterior segment SD-OCT (RTVue-100; Optovue, Inc., Fremont, CA) was used to compare regional corneal epithelial and stromal thickness in eyes with keratoconus and ectasia before CXL and 1 and 3 months after CXL. The anterior surface of the cornea, epithelium-Bowman's layer interface, and posterior reflective surface were used as anatomical landmarks to measure epithelial and stromal thickness, respectively. Regional thickness was assessed centrally and at 21 points 0.5 mm apart across the central 6 mm of the corneal vertex in the horizontal and vertical meridians., Results: Thirty-one eyes from 30 patients were evaluated, including 17 eyes (17 patients) with keratoconus and 14 eyes (13 patients) with ectasia. Preoperatively, a highly irregular epithelial thickness profile and distribution was observed in both groups. After CXL, epithelial thickness was significantly thinner 2.5 and 2 mm below and 1.5 mm above the corneal apex (49.26 ± 5.69 μm; range: 43 to 62 μm), and 2.5 and 1 mm nasal and 2 mm temporal to the corneal apex (46.66 ± 4.53 μm; range: 39 to 57 μm) compared to preoperative values (P < .05 for all measurements). Epithelial thickness standard deviations were significantly lower (by 3 to 6 μm) 3 months after CXL, compared to ranges before CXL in both the vertical and horizontal meridians for keratoconus and ectasia (P = .048). No significant differences were found between epithelial remodeling in keratoconus and corneal ectasia (P = .98). No significant or consistent stromal changes were found for either group., Conclusions: Significant epithelial remodeling occurs after CXL in eyes with keratoconus and corneal ectasia, creating a similar, more regularized thickness profile in all meridians in the early postoperative period. This pattern of remodeling may facilitate interpretation of corneal curvature and thickness changes after CXL and may be related to visual acuity after CXL., (Copyright 2014, SLACK Incorporated.)

Purpose: To assess corneal microarchitecture and regional epithelial thickness profile in eyes with keratoconus, postoperative corneal ectasia (ectasia), and normal unoperated eyes (controls) using spectral-domain optical coherence tomography (SD-OCT)., Methods: Regional corneal epithelial thickness profiles were measured with anterior segment SD-OCT (Optovue RTVue-100, Optovue Inc., Fremont, CA). Epithelial thickness was assessed at 21 points, 0.5 mm apart, across the central 6-mm of the corneal apex in the horizontal and vertical meridians., Results: One hundred twenty eyes were evaluated, including 49 eyes from 29 patients with keratoconus, 32 eyes from 16 patients with ectasia, and 39 eyes from 21 control patients. Average epithelial thickness at the corneal apex was 41.18 ± 6.47 μm (range: 30 to 51 μm) for keratoconus, 46.5 ± 6.72 μm for ectasia (range: 34 to 60 μm), and 50.45 ± 3.92 μm for controls (range: 42 to 55 μm). Apical epithelial thickness was significantly thinner in eyes with keratoconus (P < .0001) and ectasia (P = .0007) than in controls. Epithelial thickness ranges in all other areas varied widely for keratoconus (range: 21 to 101 μm) and ectasia (range: 30 to 82 μm) compared to controls (range: 43 to 64) (P = .0063)., Conclusion: SD-OCT demonstrated significant central and regional epithelial thickness profile differences between keratoconus, ectasia, and control eyes, with significant variability and unpredictability in ectatic eyes. This regional irregularity may necessitate direct epithelial thickness measurement for treatments where underlying stromal variations may be clinically relevant, including corneal collagen cross-linking or topography-guided ablations., (Copyright 2013, SLACK Incorporated.)

Purpose: To assess the corneal architecture and reproducibility of LASIK flap thickness created by the Amadeus II mechanical microkeratome (Ziemer Ophthalmic Systems AG) using Fourier-domain optical coherence tomography (OCT; Optovue Inc)., Methods: Anterior segment Fourier-domain OCT was used to analyze the morphology of 58 LASIK flaps from 30 patients created with the Amadeus II microkeratome 140-μm head and ML7090CLB blades (Med-Logics Inc) at 2 weeks postoperatively. Flap thickness was assessed at 10 points across the central 6 mm of the cornea (horizontal and vertical meridians). Postoperative central corneal flap thickness measured by Fourier-domain OCT was compared with intraoperative ultrasound pachymetry measurements., Results: No significant difference was noted between central flap thickness measured by intraoperative pachymetry (107.2 ± 14 μm) and postoperative OCT (111.7 ± 11 μm; P=.07, correlation coefficient=0.86). Fourier-domain OCT measurements demonstrated functionally planar flap architecture (standard deviation [SD] of thickness across the flap=4.9 μm, SD range across the flap=2 to 9 μm) for the microkeratome flaps., Conclusions: The Amadeus II microkeratome with Med-Logics blades created thin, reproducible, functionally planar flaps as measured by Fourier-domain OCT. Central flap thickness measured by intraoperative ultrasound pachymetry was equivalent to that measured 2 weeks postoperatively by OCT., (Copyright 2011, SLACK Incorporated.)

Purpose: To analyze and compare retreatment rates after wavefront-optimized photorefractive keratectomy (PRK) and LASIK and determine risk factors for retreatment., Methods: A retrospective chart review was performed to identify patients undergoing PRK or LASIK with the wavefront-optimized WaveLight platform from January 2005 through December 2006 targeted for a piano outcome and to determine the rate and risk factors for retreatment surgery in this population., Results: Eight hundred fifty-five eyes were analyzed, including 70 (8.2%) eyes with hyperopic refractions and 785 (91.8%) eyes with myopic refractions. After initial treatment, 72% of eyes were 20/20 or better and 99.5% were 20/40 or better. To improve uncorrected visual acuity, 54 (6.3%) eyes had retreatments performed. No significant differences in retreatment rates were noted based on age (P = .15), sex (P = .8), eye (P = .3), PRK versus LASIK (P = 1.0), room temperature (P = .1) or humidity (P = .9), and no correlation between retreatment rate and month or season of primary surgery (P = .4). There was no correlation between degree of myopia and retreatment rate. Eyes were significantly more likely to undergo retreatment if they were hyperopic (12.8% vs 6.0%, P = .006) or had astigmatism > or = 1.00 diopter (D) (9.1% vs 5.3%, P = .04)., Conclusions: Retreatment rate was 6.3% with the WaveLight ALLEGRETTO WAVE excimer laser. This rate was not influenced by age, sex, corneal characteristics, or environmental factors. Eyes with hyperopic refractions or astigmatism > or = 1.00 D were more likely to undergo retreatment.

Purpose: To report cases of granular corneal dystrophy type II (Avellino corneal dystrophy) that were exacerbated by uncomplicated laser epithelial keratomileusis (LASEK) for myopia., Methods: Eight patients (15 eyes) with granular corneal dystrophy type II who underwent LASEK were examined by DNA sequencing, slit-lamp microscopy, and confocal microscopy., Results: The number and density of the opacities increased after LASEK. Best spectacle-corrected visual acuity decreased after LASEK as the density of the opacities increased. In three patients, mitomycin C was used intraoperatively, but corneal deposits also worsened in these patients., Conclusions: LASEK is contraindicated in patients with granular corneal dystrophy type II because vision may be reduced from an increase in the density of corneal opacities postoperatively.

Purpose: To report the clinical features and outcome of eyes with flap buttonhole during LASIK., Methods: A retrospective review was performed to identify eyes that developed flap buttonhole during Hansatome microkeratome translation. Pre-, intra-, and postoperative data were obtained to identify factors predictive of buttonhole., Results: Five patients with buttonhole were identified from June 2001 through September 2002 (5 [0.06%] eyes of 7672 primary LASIK procedures). Mean patient age was 49.2 +/- 11.3 years (range: 37 to 66 years). Mean preoperative spherical equivalent refraction was 4.92 +/- 2.90 diopters (D) (range: -2.25 to -9.50 D). Mean keratometry was 45.59 +/- 1.15 D (range: 43.90 to 47.60 D). All 5 flap buttonholes occurred in the second of 2 consecutively treated eyes (P = .03). Buttonhole occurred in 2 (0.26%) of 778 eyes where the 160-microm microkeratome plate was used, and 3 (0.06%) of 4350 eyes where the 180-microm plate was used (P = .16). Two eyes received laser ablation at the time of buttonhole formation. In the untreated cases, the buttonhole flap itself caused a myopic spherical change of -0.50 D and 0.70 D of astigmatism. One of 5 eyes lost 2 lines of best spectacle-corrected visual acuity; this eye received laser ablation immediately after buttonhole formation., Conclusions: Buttonholes are significantly more likely to occur in the second of two consecutively treated eyes. A new blade for the second eye when the flap in the first eye appears to be thin should be considered. Caution should be exercised when considering laser ablation immediately following buttonhole formation.

Purpose: To report two cases of corneal ectasia, which developed after hyperopic LASIK., Methods: Preoperative pellucid marginal corneal degeneration was observed in patient 1. Patient 2 had no preoperative risk factors., Results: Patient 1, a 47-year-old man, developed corneal ectasia in his right eye 6 months after unilateral hyperopic LASIK. Preoperative manifest refraction was +2.00 +1.50 x 178 in the right eye and +1.00 sphere in the left eye. Corneal thickness was 585 microm and 575 microm (right and left eye, respectively). Preoperative topography of the right eye demonstrated inferior steepening in the far periphery, suggestive of early pellucid marginal corneal degeneration. Patient 2, a 35-year-old man, developed corneal ectasia in his right eye > 3 years after bilateral LASIK. Preoperative manifest refraction was +2.50 sphere and +3.25 sphere (right and left eye, respectively), and corneal thickness was 556 microm in both eyes. Preoperative topography was normal in both eyes with no evidence of asymmetry, steepening, or irregularity., Conclusions: Corneal ectasia can occur after hyperopic LASIK in patients with or without recognized preoperative risk factors. Although uncommon, patients with pellucid marginal corneal degeneration can have hyperopic refractions and are at high risk for developing corneal ectasia after LASIK.

Purpose: To develop a minimum set of analyses and a format for presentation of outcomes of astigmatism correction by laser systems that reshape the cornea., Methods: An Astigmatism Project group was created under the auspices of the American National Standards Institute (ANSI) Z80.11 Working Group on Laser Systems for Corneal Reshaping. The Astigmatism Project Group was made up of experts in astigmatism analyses from academia, government, and industry. An extensive literature review was conducted to identify all currently available methodologies for the evaluation of astigmatic outcomes. Project Group members discussed the utility of each method and its specific parameters for evaluating the effectiveness of astigmatism-correcting devices. They gave consideration to unique terminology and analyses required for evaluation of correction of astigmatism by laser systems that reshape the comea., Results: The Project Group defined a comprehensive list of analysis variables needed for the evaluation of astigmatism-correcting devices and generated a mathematical definition for each term. They developed a minimum set of analyses needed for evaluation of astigmatism treatments by laser systems that reshape the cornea. They established methods for calculating the refractive error analysis variables and constructed recommended table and graph formats for data presentation., Conclusions: This article contains the recommendations of the Astigmatism Project Group of the American National Standards Institute. We propose it as a standard reference for astigmatic refractive error analyses for the evaluation of safety and effectiveness of laser systems that reshape the cornea.

Purpose: To show a specific relationship between monocular diplopia and corneal refractive asymmetry after laser in situ keratomileusis (LASIK)., Methods: One hundred thirty-eight eyes of 98 patients who underwent LASIK for myopia between -2.12 and -17.75 D were examined under room-lighted conditions. We examined 51 eyes at 2 weeks, 46 eyes at 3 months, 32 eyes at 6 months, and 9 eyes at 1 year after LASIK. We attempted to correlate the presence of monocular diplopia with their corneal topographical features., Results: Eight eyes of five patients (five eyes at 2 weeks, three eyes at 3 months after LASIK) produced symptoms of monocular diplopia. These symptomatic patients had a common corneal topographical feature caused by decentralized or inhomogeneous ablation. Every pupillary area in the patients' topographies contained steeper and flatter areas. The range of refractive power variation in these asymmetric areas was at least 1.50 D. The location of the secondary image correlated with the direction of the steeper area in all eight eyes. Pinhole viewing eliminated or reduced the prominence of secondary images in every case., Conclusion: Monocular diplopia following LASIK appears to correlate with postoperative corneal refractive power variation inside the pupillary area, caused by decentralized or inhomogeneous ablation.

Purpose: We report a case of keratolysis following phototherapeutic keratectomy (PTK) for a subepithelial nodule in a patient with keratoconus., Methods: A 29-year-old male with keratoconus who became contact lens intolerant because of a raised subepithelial nodule was treated with excimer laser phototherapeutic keratectomy (PTK)., Results: The epithelium failed to heal postoperatively, and progressive keratolysis led to a central descemetocele by the eighth postoperative day. The patient was managed with a penetrating keratoplasty., Conclusions: Excimer laser phototherapeutic keratectomy has been shown to be an effective treatment for subepithelial nodules in patients with keratoconus. Rapidly progressive keratolysis is a potential complication of this procedure.

Purpose: To construct a quantitative model relating refractive results to laser settings and other factors., Methods: A prospective clinical trial was performed, including 14 surgeons and 523 eyes of 278 patients who desired correction of myopia from -1.00 to -16.00 D (mean, -6.20 D) and astigmatism up to 6.00 D (mean, 1.10 D). Myopia and astigmatism were corrected by laser in situ keratomileusis (LASIK) with sequential spherical and cylindrical ablations using a 5.5-mm ablation zone and a transition zone to 7.0 mm. The Nidek EC-5000 excimer laser and the Chiron Automated Corneal Shaper were used., Results: Surgically induced refractive changes 3 months after surgery were measured. Spherical ablation by LASIK produced a 19% greater refractive change than that predicted by the Nidek PRK algorithm. The laser setting needed to achieve each 1.00 D of cylinder correction induced 1.30 D change in spherical equivalent refraction (0.80 D more than expected). Patient age and nonlinear effects had small but statistically significant influences on refractive outcome. Sex, left/right eye, and surgeon were not significant factors. Residual variations in spherical equivalent refraction included a 0.50-D constant plus 9% of the predicted spherical equivlanet change. Residual variations in the parallel and orthogonal components of cylinder correction were, respectively, 28% and 13% of the predicted cylinder change plus a 0.30-D constant component. The standard deviation of axis alignment error for cylinder ablation was 3.7 degrees., Conclusions: Cylindrical ablation produced a spherical change that was larger than expected. To compensate for this, spherical ablation should be reduced in eyes with astigmatism. Variability in the correction of astigmatism was proportionally larger than that for spherical correction and was primarily due to magnitude rather than axis error.

Background: We utilized videokeratography to determine the frequency of keratoconus suspects in a refractive surgery population, and compared the results of refractive keratotomy in these patients to those of patients with normal corneal topography., Methods: The records of 67 consecutive patients (120 eyes) undergoing refractive keratotomy were reviewed retrospectively. Quantitative measurements of relative inferior corneal steepening (inferior-superior value, I-S value) were obtained from preoperative videokeratography., Results: Three of 120 eyes (3 of 67 patients, 4.5%) were identified as keratoconus suspects based on I-S (inferior-superior) values greater than +1.74 (range, +1.76 to +2.00), which represented two standard deviations (+/- 0.66) above the mean (+0.42). All three of these eyes achieved postoperative uncorrected visual acuity of 20/30 or better. Of those eyes with normal preoperative topography (I-S value +1.74 or less), 90 of 112 (80%) achieved postoperative uncorrected visual acuity of 20/30 or better, and 105 of 112 (94%) achieved 20/40 or better., Conclusions: Although long-term follow up is needed to confirm stability of refractive surgery outcome, it appears that keratoconus suspects can obtain acceptable results with refractive keratotomy. Studies on larger patient populations using videokeratography are needed to better define keratoconus, keratoconus suspects, and normal variants of corneal topography and to determine how eyes with abnormal topography respond to refractive keratotomy.