The effects of programmed optical zones on achieved corneal refractive power with myopic astigmatism after small incision lenticule extraction (SMILE): a vector analysis.

PURPOSE: To evaluate the effects of different programmed optical zones (POZs) on achieved corneal refractive power (CRP) with myopic astigmatism after small incision lenticule extraction (SMILE). METHODS: In total, 113 patients (113 eyes) were included in this retrospective study. The eyes were divided into two groups according to POZ: group A (6.5, 6.6, and 6.7 mm, n = 59) and group B (6.8, 6.9, and 7.0 mm, n = 54). Fourier vector analysis was applied to evaluate the error values between the attempted and achieved corneal refractive power (CRP). Alpins vector analysis was used to calculate surgically induced astigmatism (SIA), difference vector (DV), magnitude of error (ME), and astigmatism correction index (ACI). Multivariate regression analysis was performed to assess potential factors associated with the error values. RESULTS: The error values in the group with large POZ were closer to zero, and significantly associated with the POZ at 2 and 4 mm of the cornea (ß = - 0.50, 95% confidence interval [CI] [- 0.80, - 0.20]; ß = - 0.37, 95% CI [- 0.63, - 0.10], P < 0.05, respectively). For the correction of astigmatism, the values of SIA, ME, and ACI were lower in group B than in group A (P < 0.05). The fitting curves between TIA and SIA were y = 0.83x + 0.19 (R2 = 0.84) and y = 1.05x + 0.04 (R2 = 0.90), respectively. CONCLUSIONS: Smaller POZs resulted in higher error values between the achieved- and attempted-CRP in the SMILE procedure, which should be considered when performing surgery.

Accelerated corneal collagen cross-linking in progressive keratoconus: Five-year results and predictors of visual and topographic outcomes.

Purpose: To analyze the 5-year results of accelerated corneal collagen crosslinking (CXL) for progressive keratoconus and identify preoperative characteristics predictive of visual and topographic outcomes. Methods: A prospective interventional case series. Nineteen eyes of 19 patients receiving accelerated CXL with settings of 18 mW/cm2 for 5 min were included. Clinical and topographic parameters were assessed. Linear regression and logistic regression were used to compare the R2 and odds ratio (OR), respectively, between baseline characteristics and postoperative outcomes. Results: Corrected distance visual acuity (CDVA) remained stable from 0.28 ± 0.21 to 0.25 ± 0.18 logMAR (P = 0.486). The mean cylindrical refraction was stable (P = 0.119). The maximal keratometry (Kmax) decreased from 61.99 ± 10.37 to 59.25 ± 7.75 D (P < 0.001), flattening in the flattest and steepest meridians and mean keratometry were also observed (P ≤ 0.040). The mean anterior elevation at the apex reduced from 21.42 ± 16.69 to 18.53 ± 12.74 µm (P = 0.013) and changes in posterior elevation were non-significant (P = 0.629). Preoperative Kmax best predicted the postoperative change in Kmax (R2 = 0.55, P < 0.001) compared to the other baseline characteristics (P ≤ 0.028), whereas preoperative CDVA was the only significant predictor of postoperative change in CDVA (R2 = 0.41, P = 0.003). Accelerated CXL is less likely to fail in eyes with a steeper preoperative Kmax (OR = 0.74, P = 0.040) or greater posterior elevation at the apex (OR = 0.91, P = 0.042). Conclusion: Kmax significantly decreased following accelerated CXL. Eyes with worse preoperative CDVA and higher Kmax were more likely to have an improvement in visual acuity and corneal flattening.

Five-Year Changes in Corneal Astigmatism After Combined Femtosecond-Assisted Phacoemulsification and Arcuate Keratotomy.

PURPOSE: To investigate the long-term stability of corneal astigmatism after combined femtosecond (fs)-assisted phacoemulsification and arcuate keratotomy. DESIGN: Retrospective, interventional case series. METHODS: Surgery was performed using a Victus (Bausch & Lomb) platform. A single, 450-µm-deep arcuate keratotomy was paired at the 8-mm zone with the main phacoemulsification incision in the opposite meridian. The keratotomy incisions were not opened. Corneal astigmatism measurements obtained preoperatively and at 2 and 5 years postoperatively were analyzed using vector analysis. RESULTS: A total of 44 eyes of 44 patients (mean age 66.0 ± 10.1 years) were included. The mean preoperative corneal astigmatism was 1.40 ± 0.66 diopters (D). This was reduced to 0.74 ± 0.54 D at 2 years and 0.70 ± 0.50 at 5 years postoperatively (P < .001). There were no statistically significant differences between postoperative corneal astigmatism at 2 years and at 5 years (P = .609). Both magnitude of error and absolute angle of error were comparable between the 2 postoperative time points (P > .805). At the end of 5 years, 65% of the eyes were within 15 degrees of the preoperative astigmatic meridian. Comparative analysis showed significantly higher surgically induced astigmatism, lower differences in vector and absolute angles of error for the eyes with preoperative with-the-rule (WTR) astigmatism than eyes with against-the-rule (ATR) astigmatism at 5 years (P < .004). CONCLUSIONS: Our study showed the stability of femtosecond (fs)-assisted arcuate keratotomy was well-maintained over 5 years. There was a tendency of increasing overcorrection of preoperative WTR astigmatism and undercorrection of ATR astigmatism over time.

The Tenons' Layer Reposition Approach of Trabeculectomy: A Longitudinal Case Series of a Mixed Group of Glaucoma Patients.

SYNOPSIS: This 1-year prospective study demonstrated that the Tenon's layer reposition approach of trabeculectomy could achieve zero leakage rate, minimal rate of transient hypotony without compromising the surgical outcome. PURPOSE: The purpose of this study was to investigate the effectiveness and safety of a Tenon's layer reposition approach of trabeculectomy. METHODS: A prospective, noncomparative case series of 30 eyes of 30 Chinese patients with mixed types of glaucoma who underwent fornix-based trabeculectomy combined with intraoperative mitomycin C application. During the conjunctival flap closure, the Tenons' layer was identified, separated, and anchored on to the sclera surface with 8/0 vicryl, followed by conjunctival closure with 10/0 nylon as a separate layer. All patients were followed up for 1 year. Assessment including intraocular pressure (IOP), vertical cup-disc ratio measurement, best-corrected visual acuity, and visual field examination were performed before and after the operation. Qualified and complete success was defined as IOP of ≤21 mm Hg in 2 consecutive visits with or without medication, respectively. Outcomes were evaluated using scattered plot and Kaplan-Meier survival curve. RESULTS: Twenty-one eyes (70%) and 28 eyes (93.3%) achieved complete and partial success at 1 year, respectively. There was a significant reduction of IOP (28.5±9.6 to 15.5±2.6 mm Hg, P<0.001) and medication use (4.4±0.9 to 0.8±1.2 bottles/eye, P<0.001). There were no significant changes in best-corrected visual acuity, vertical cup-disc ratio, and visual field indices. No wound leak was identified throughout the study. The procedure did not induce significant astigmatic change. Other postoperative complications, including 2 eyes (6.7%) with transient hypotony and 1 eye (3.3%) required cataract surgery, were of relatively low rate. CONCLUSION: The Tenon's layer reposition approach of performing trabeculectomy is a safe and efficacious procedure for Chinese subjects with different types of glaucoma.

The Effect of Intraoperative Angle Kappa Adjustment on Higher-Order Aberrations Before and After Small Incision Lenticule Extraction.

PURPOSE: To compare higher-order aberrations (HOAs) after small incision lenticule extraction (SMILE) in patients with and without intraoperative angle kappa adjustments. METHODS: This is a retrospective case series. One hundred six eyes of 106 patients who underwent SMILE at Tianjin Eye Hospital (Tianjin Medical University, Tianjin, China) for correction of myopia and myopic astigmatism were divided into 2 groups. The first group consisted of eyes with intraoperative angle kappa adjustment and the second group consisted of eyes without adjustment. Preoperative and postoperative visual outcome, refraction, and HOA measurements at 1 and 3 months were compared. RESULTS: At the pupil size of 6 mm, vertical coma at 1 and 3 months after SMILE for the angle kappa-adjusted group was 0.153 ± 0.107 and 0.157 ± 0.094 µm, which were significantly lower than those of the nonadjusted group (0.204 ± 0.117 and 0.203 ± 0.113 µm, respectively) (P = 0.026 at 1 mo, P = 0.047 at 3 mo). The change in vertical coma between preoperative and postoperative measurements was 0.011 ± 0.136 and 0.023 ± 0.129 µm at 1 and 3 months postoperatively for the angle kappa-adjusted group, which were lower than those of the nonadjusted group (0.082 ± 0.165 and 0.085 ± 0.150 µm, respectively) (P = 0.023 at 1 mo, P = 0.045 at 3 mo). Subgroup analysis for eyes with large angle kappa demonstrated that the vertical coma was significantly less in the angle kappa-adjusted group at both 1 and 3 months (P = 0.009, P = 0.043, respectively). No significant correlation was observed between angle kappa and HOAs in the angle kappa-adjusted group. CONCLUSIONS: Adjustment of angle kappa during SMILE resulted in less HOAs. It would provide more insight on how to optimize treatment centration in SMILE.

Transient corneal ectasia after phacoemulsification in an eye with femtosecond intrastromal presbyopic treatment.

We report a case of transient corneal ectasia developed after phacoemulsification in an eye previously treated with INTRACOR. There was a myopic refractive surprise after cataract surgery. Corneal tomography showed an increase in keratometry and elevation profile compared with preoperative examination. Soft contact lenses and intraocular pressure-lowering medications were prescribed as interim treatment. Clinical improvement was seen gradually, and the resolution of myopia and ectasia was achieved at 3 months. We believe that high intraocular pressure during phacoemulsification and the weakening effect of femtosecond intrastromal presbyopic treatment can be the culprits.

Fluctuation in straylight measurements during the visual recovery phase after small incision lenticule extraction.

PURPOSE: To investigate the postoperative straylight changes during the visual recovery phase after small incision lenticule extraction (SMILE) and their association. METHODS: Seventy consecutive eyes from 37 patients with a mean age of 30.92 ± 7.26 years and a mean preoperative spherical equivalent of -5.24 ± 1.90 dioptres undergoing myopic or myopic astigmatism SMILE correction were included in this prospective study. Patients were followed up at days 1, 3, 7, 14, 21 and 28 after standard SMILE. Straylight was measured using the C-Quant straylight meter (Oculus GmbH, Germany) preoperatively and at each postoperative visit. RESULTS: Preoperatively, the mean straylight measurement was 1.16 ± 0.16. After SMILE, the mean straylight values were 1.12 ± 0.14 and 1.13 ± 0.13 at days 7 and 14, which were significantly reduced compared to preoperative values (p ≤ 0.028). Straylight returned to baseline by week 3 (p = 0.160) and remained stable onwards (p = 0.651). A lower ablation ratio was associated with less straylight level at days 1, 3, 14 and 21 (p ≤ 0.0497) in the multivariable regression model. Likewise, better visual acuity was associated with lower straylight at days 7, 14 and 28 postoperatively (p ≤ 0.038). A small proportion of eyes (range: 0-12.86%) had ≥0.30 log(s) increase in postoperative straylight within the first month after SMILE. CONCLUSIONS: SMILE induced a temporary decrease in straylight. It gradually returned to the preoperative level, which could be related to a number of dynamic processes during corneal healing. In the small proportion of patients with an increase in straylight postoperatively, this can affect their visual recovery during the early postoperative period.

Outcomes of presbyopia-correcting intraocular lenses after laser in situ keratomileusis.

BACKGROUND: Laser in situ keratomileusis (LASIK) is the most common refractive surgery in young patients, which aims at providing a clear distance vision without the use of spectacles. With time, these patients develop symptomatic cataract, which affects activities of daily living, and to improve visual acuity, intraocular lens (IOL) implantation can be considered. In post-myopic LASIK patients, to allow continuation of spectacle independence, the implantation of presbyopia-correcting IOLs is a suitable option. The purpose of this retrospective case series is to report the visual outcome and quality in post-myopic LASIK eyes after the implantation of AT LISA tri839MP IOL. METHOD: Twenty eyes of 13 patients with history of myopic LASIK within 20 years underwent phacoemulsification by one single surgeon. All eyes were implanted with AT LISA tri839PMP IOL, and their outcomes were evaluated at 6 months postoperation. RESULTS: The mean postoperative uncorrected distance visual acuity (VA) is 0.28 ± 0.29, while the corrected distance VA is 0.06 ± 0.14. The mean postoperative uncorrected near VA is 0.02 ± 0.05, while the corrected near VA is 0.01 ± 0.02. The mean postoperative manifest refraction spherical equivalent (SE) is - 0.92 ± 0.76D. There is a statistically significant difference between the preoperative and postoperative refraction (p = 0.02), which shows a postoperative myopic shift. There is also a statistically significant difference between the mean targeted SE and postoperative manifest refraction SE (p = 0.00). Only one out of 20 eyes (5%) reported halo and glare symptoms. Ten out of 20 eyes (50%) are able to achieve spectacles independence. CONCLUSION: In conclusion, in post-myopic LASIK eyes, AT LISA tri839MP provides a good visual outcome at both near and distance, but is more predictable at near than at distance. There is a myopic shift in the postoperative SE. Visual quality is satisfactory and has not been exacerbated. Most patients can remain to be spectacles free at all distances.

Comparison of Corneal Tomography and a New Combined Tomographic Biomechanical Index in Subclinical Keratoconus.

PURPOSE: To investigate and compare the diagnostic ability of corneal tomography and biomechanical and combined parameters for detection of corneal ectasia. METHODS: Consecutive patients with subclinical keratoconus (SCKC) and age-matched controls were included. Only one eye from each patient was selected for analysis. The final D value from the Belin/Ambrósio Enhanced Ectasia Display (BAD) was obtained from the Pentacam (Oculus Optikgeräte, Wetzlar, Germany). The tomographic biomechanical index (TBI) was derived from the Pentacam and Corvis ST (Oculus Optikgeräte). Classification analysis between normal and subclinical keratoconus (SCKC) was evaluated using receiver operating characteristic (ROC) curves. The area under the ROC curve (AUC) and partial AUC (pAUC) with specificity of 80% or greater were compared. RESULTS: Twenty-three eyes with SCKC and 37 normal eyes were included. All Pentacam-derived parameters (P < .001) and all but two Corvis ST-derived parameters (P < .020) were significantly different between normal and SCKC eyes. A significant difference was found in the final D value (P ≤ .020) and TBI (P ≤ .040) between normal and SCKC eyes. For differentiating normal and SCKC eyes, TBI and BAD final D value demonstrated the highest AUC (0.925 and 0.786, respectively) and pAUC (0.150 and 0.088, respectively). TBI demonstrated 84.4% sensitivity and 82.4% specificity using a cut-off of 0.16. Comparative analysis between these parameters showed that AUC and pAUC of TBI were significantly higher than all parameters from Pentacam (P ≤ .032). CONCLUSIONS: In the current study, combined use of tomographic and biomechanical parameters demonstrated a higher capability in differentiating normal and SCKC eyes when compared to tomographic analysis alone. [J Refract Surg. 2018;34(9):616-621.].

Survival Analysis of Corneal Densitometry After Collagen Cross-Linking for Progressive Keratoconus.

PURPOSE: To evaluate the history of densitometric data in patients with keratoconus undergoing corneal cross-linking. METHODS: Twenty-two eyes of 22 patients with keratoconus were included. Corneal tomography and densitometry measurements were performed before and after accelerated corneal cross-linking. The duration of corneal haze was defined as the time between cross-linking and densitometry measurements returning to the preoperative value. Survival analysis of corneal haze after cross-linking was performed. Preoperative and postoperative corneal densitometry, maximum keratometry (Kmax), and central corneal thickness were compared. RESULTS: The duration of corneal haze was 18.2 ± 3.8 months at the first zone of 0 to 2 mm and 10.9 ± 2.5 months at the second zone of 2 to 6 mm. There was no change in Kmax between the preoperative period and the time at which corneal haze resolved (P = 0.394 at the first zone; P = 0.658 at the second zone). Compared with the measurement taken at resolution of corneal haze, Kmax at 1 year after haze resolution was lower (62.0 ± 9.9 D to 61.2 ± 9.9 D, P = 0.008 at the first zone; 63.6 ± 10.9 D to 62.5 ± 10.1 D, P = 0.016 at the second zone). There was a decrease of central corneal thickness between the preoperative period and the time at which corneal haze resolved (470.8 ± 34.1 µm to 464.8 ± 34.5 µm, P = 0.047 at the first zone; 465.0 ± 35.3 µm to 454.7 ± 37.2 µm, P = 0.001 at the second zone), but it remained unchanged after haze resolution (P = 0.146 at the first zone; P = 0.067 at the second zone). CONCLUSIONS: Corneal cross-linking halted keratoconus progression when detectable haze was present. There was continuous corneal flattening measured at 1 year after haze resolution. Thinning of the cornea was seen only when haze was detectable after cross-linking.

Vector analysis of high (≥3 diopters) astigmatism correction using small-incision lenticule extraction and laser in situ keratomileusis.

PURPOSE: To compare the astigmatic correction in high myopic astigmatism between small-incision lenticule extraction and laser in situ keratomileusis (LASIK) using vector analysis. SETTING: Hong Kong Laser Eye Center, Hong Kong. DESIGN: Retrospective case series. METHODS: Patients who had correction of myopic astigmatism of 3.0 diopters (D) or more and had either small-incision lenticule extraction or femtosecond laser-assisted LASIK were included. Only the left eye was included for analysis. Visual and refractive results were presented and compared between groups. RESULTS: The study comprised 105 patients (40 eyes in the small-incision lenticule extraction group and 65 eyes in the femtosecond laser-assisted LASIK group.) The mean preoperative manifest cylinder was -3.42 D ± 0.55 (SD) in the small-incision lenticule extraction group and -3.47 ± 0.49 D in the LASIK group (P = .655). At 3 months, there was no significant between-group difference in uncorrected distance visual acuity (P = .915) and manifest spherical equivalent (P = .145). Ninety percent and 95.4% of eyes were within ± 0.5 D of the attempted cylindrical correction for the small-incision lenticule extraction and LASIK group, respectively (P = .423). Vector analysis showed comparable target-induced astigmatism (P = .709), surgically induced astigmatism vector (P = .449), difference vector (P = .335), and magnitude of error (P = .413) between groups. The absolute angle of error was 1.88 ± 2.25 degrees in the small-incision lenticule extraction group and 1.37 ± 1.58 degrees in the LASIK group (P = .217). CONCLUSION: Small-incision lenticule extraction offered astigmatic correction comparable to LASIK in eyes with high myopic astigmatism.

Comparing a new hydroexpression technique with conventional forceps method for SMILE lenticule removal.

BACKGROUND: We described a modified 'hydroexpression' technique for the lenticule removal during small-incision lenticule extraction (SMILE) surgery and compared the results with conventional forceps method. METHODS: This was a retrospective, comparative study of 50 patients who underwent SMILE surgery by the same surgeon. We compared the 1-week and 3-months postoperative results after SMILE using the hydroexpression technique with the conventional forceps technique. Main outcome measures included uncorrected distance visual acuity, corrected distance visual acuity, refractive accuracy, safety index and efficacy index. RESULTS: The baseline characteristics were comparable between both groups. At postoperative 1 week, the safety index in forceps and hydroexpression group was 0.93±0.11 and 0.97±0.10, respectively (P=0.246). At 3 months, they were 1.00±0.06 and 0.99±0.09 (P=0.850). For efficacy indices, at 1 week they were 0.84±0.17 and 0.91±0.17 (P=0.158). At 3 months, they were 0.92±0.13 and 0.94±0.19 (P=0.624). All eyes aimed for a plano target. 96% in forceps group and 90% in hydroexpression group were within ±0.50 dioptre (D) in spherical equivalent refraction (SEQ) correction at postoperative 3 months (P=0.567). The mean errors of SEQ correction were -0.10±0.21 D in forceps group and -0.08±0.30 D in hydroexpression group (P=0.705). CONCLUSION: Hydroexpression was simple and safe and had early results comparable to the conventional forceps technique. This technique was particularly useful for cases with more adhesions between lenticule and anterior cap, thin lenticule cases and for the inexperienced SMILE surgeons.

Early epithelial complications of accelerated trans-epithelial corneal crosslinking in treatment of keratoconus: a case series.

BACKGROUND: To report a case series of early postoperative complications following combined accelerated corneal crosslinking (CXL) and trans-epithelial technique in keratoconus. CASE PRESENTATIONS: Eleven eyes underwent accelerated trans-epithelial CXL (18 mW/cm2 for 5 min). Seven eyes (64%) developed complications in the first week postoperatively. Five eyes had large epithelial defects, and two eyes were complicated with diffuse punctate epithelial erosions. Early transient stromal haze was seen in eyes with epithelial complications. Anterior segment optical coherence tomography showed a faint demarcation line in six eyes (55%) with epithelial complications. CONCLUSION: A significant number of eyes developed epithelial complications shortly after combined accelerated trans-epithelial CXL, which defeated the benefits of leaving the epithelium intact.

Determining total corneal power after small-incision lenticule extraction in myopic eyes.

PURPOSE: To evaluate the methods to correct corneal power after myopic small-incision lenticule extraction (SMILE) and to estimate the preoperative corneal power based on postoperative values. SETTING: Tianjin Eye Hospital, Tianjin, China. DESIGN: Retrospective case series. METHODS: Equivalent keratometry (K) and mean K readings were obtained with the Pentacam HR. The clinical history method was used to calculate the theoretical postoperative K, which was then compared with equivalent K readings. In addition, the anterior-posterior (A-P) method was used to estimate the preoperative mean K. The agreement between computed and actual values was estimated using the Bland-Altman method. RESULTS: A significant correlation was observed between the theoretical postoperative K (38.52 diopters [D] ± 1.57 [SD]) and mean K after surgery (39.44 ± 1.43 D) (R2 = 0.9317, P < .001). The mean equivalent K readings at 4.0 mm, 4.5 mm, and 5.0 mm were not significantly different from the theoretical postoperative K values (P = .620, P = .514, and P = .622, respectively). Bland-Altman plots showed a high level of agreement when comparing the theoretical postoperative K with the clinical history K (-0.94 to +0.9 D, -0.83 to +0.88 D, and -0.84 to +0.88 D, respectively). In addition, the estimated preoperative mean K (43.28 ± 1.31 D) derived by the A-P method was comparable to the measured mean K (P = .111). CONCLUSIONS: Equivalent K readings provided a relatively good estimation of corneal power in eyes after small-incision lenticule extraction. The A-P method might be an option to predict preoperative corneal power.

Secondary Lenticule Remnant Removal After SMILE.

PURPOSE: The authors report four cases of residual intrastromal lenticule after seemingly uneventful small incision lenticule extraction (SMILE) surgery and the outcome after a secondary procedure to remove the lenticule remnant. METHODS: Case reports. RESULTS: All four cases presented with suboptimal corrected distance visual acuity (CDVA) and refractive surprise. Irregularities in the corneal curvature and elevation were detected on corneal topography and tomography. Careful review of the intraoperative video showed an incomplete removal of the SMILE lenticule. All four cases underwent a secondary surgical procedure to remove the residual lenticule remnant. All cases had improvements in the CDVA, refraction, and topography, with the CDVA returning to the preoperative value (20/20) in all cases. CONCLUSIONS: Performing an early, secondary lenticular remnant removal operation is feasible, safe, and can result in improvement in both refraction and visual acuity. During the original SMILE surgery, surgeons should routinely examine the removed lenticule for completeness. [J Refract Surg. 2017;33(11):779-782.].

Comparison of Corneal Dynamic and Tomographic Analysis in Normal, Forme Fruste Keratoconic, and Keratoconic Eyes.

PURPOSE: To investigate and compare the diagnostic ability of corneal tomography and dynamic corneal response to differentiate between normal eyes and those with forme fruste keratoconus and keratoconus. METHODS: Corneal tomography was performed using Pentacam (Pentacam HR; Oculus Optikgeräte, Wetzlar, Germany). Corneal deformation response was captured via Corvis ST (Optikgeräte) using a beta version of Corvis software. Classification analysis between normal eyes and eyes with forme fruste keratoconus and between normal and keratoconic eyes was evaluated using receiver operating characteristic curves. The area under the ROC curve (AUC) and partial AUC (pAUC) for each classifying parameter were compared. RESULTS: Twenty-one patients with forme fruste keratoconus in one eye and clinically evident keratoconus in the fellow eye and 38 normal individuals were recruited. Overall, 21 eyes with forme fruste keratoconus and 18 eyes with keratoconus were compared with 73 normal eyes. The mean age of the participants was comparable between groups. Comparative analysis between Pentacam and Corvis ST parameters showed significantly lower AUC and pAUC for Corvis ST parameters in differentiating keratoconic from normal eyes (P ≥ .049). However, comparable AUC and pAUC was observed between the Corvis Biomechanical Index (AUC = 0.785; pAUC = 0.079) and D value of the Belin/Ambrósio Enhanced Ectasia Display (AUC = 0.757; pAUC = 0.068) (P ≥ .477) for detection of forme fruste keratoconus with sensitivities of 63.2% and 52.6%, given a common specificity of 80.3%. CONCLUSIONS: The current study showed the feasibility of use of non-tomographical parameters obtained from the Corvis ST for differentiating normal eyes and those with forme fruste keratoconus and keratoconus. The diagnostic ability of the Corvis ST was comparable to that of the Pentacam for differentiating normal eyes and eyes with forme fruste keratoconus. [J Refract Surg. 2017;33(9):632-638.].

Shift in progression rate of keratoconus before and after epithelium-off accelerated corneal collagen crosslinking.

PURPOSE: To evaluate the shift in keratoconus progression rate after corneal collagen crosslinking (CXL). SETTING: Chinese University of Hong Kong Eye Centre, Hong Kong, China. DESIGN: Prospective case series. METHOD: Accelerated epithelium-off CXL was performed in patients with progressive keratoconus. Optical coherence tomography-based corneal measurements were recorded. The data collected after the first postoperative month were used for analysis. The main outcome measure was the rate of progression of steep keratometry (K), flat K, average K, and best-fit sphere (BFS) using linear mixed-effects models. Progression was defined based on a significant slope against time in these models. RESULTS: Forty-seven eyes (38 patients; mean age 27.6 years ± 6.5 [SD]) were included. The median number of preoperative visits and postoperative visits was 3 and 5, respectively. A significant reduction in the progression rate of the anterior average K (0.063 ± 0.138 diopter [D]/mo to -0.022 ± 0.029 D/mo) and posterior average K (-0.011 ± 0.025 D/mo to 0.000 ± 0.009 D/mo) occurred (both P < .001). On univariate analysis, the baseline anterior average K had the strongest association with the progression rate of the anterior average K after CXL. On multivariate analysis, the preoperative progression rate of the posterior BFS was significantly associated with postoperative progression rate of the anterior (P < .001) and posterior average K (P ≤ .05). CONCLUSIONS: A significant reduction in the progression rate of average K occurred after accelerated epithelium-off CXL. The reduction was associated with the baseline anterior average K and preoperative progression of posterior BFS.

Influence of Refractive Status on the Higher-Order Aberration Pattern After Small Incision Lenticule Extraction Surgery.

PURPOSE: To study the effect of myopia on the pattern change in higher-order aberrations after small incision lenticule extraction. METHODS: Sixty eyes of 60 patients were included: low myopia (≤-3.00 D), moderate myopia (-3.00 D to -6.00 D), and high myopia (≥-6.00 D). Total higher-order aberrations (tHOA), vertical coma ((Equation is included in full-text article.)), horizontal coma ((Equation is included in full-text article.)), and spherical aberration ((Equation is included in full-text article.)) were measured preoperatively and at postoperative 3 months. RESULTS: At the end of 3 months, tHOA changed significantly compared with the preoperative values (P < 0.05), except for (Equation is included in full-text article.)and (Equation is included in full-text article.)in the low myopia group. The change in (Equation is included in full-text article.), (Equation is included in full-text article.), and (Equation is included in full-text article.)in the moderate group (-0.299, -0.175, and 0.108 µm) was 2.020, 4.861, and 4.696 times higher than the low group (-0.148, -0.036, 0.023 µm) (P = 0.002, 0.001, 0.001), respectively. The value in the high group (-0.331, -0.192, 0.154 µm) was 1.107, 1.097 (P = 0.478, 0.665), and 1.426 times (P = 0.047) higher than the moderate group. The degree of myopia was positively correlated with Δ(Equation is included in full-text article.)(r = 0.447; P < 0.001) and Δ(Equation is included in full-text article.)(r = 0.496; P < 0.001), and negatively correlated with ΔtHOA (r = -0.363, P = 0.004) and Δ(Equation is included in full-text article.)(r = -0.599; P < 0.001). CONCLUSIONS: The study showed a different pattern of change in ocular aberrations after small incision lenticule extraction in patients with varying degrees of myopia. In patients with low myopia, there was no increase in (Equation is included in full-text article.)or (Equation is included in full-text article.). In high myopia, however, (Equation is included in full-text article.)increased with the degree of myopia, whereas the rising rate of coma was slowing.

Effect of the Learning Curve on Visual and Refractive Outcomes of Small-Incision Lenticule Extraction.

PURPOSE: To investigate the effect of the learning curve for small-incision lenticule extraction during the first 2 years of experience. METHODS: Small-incision lenticule extraction was performed using the 500-kHz VisuMax femtosecond laser (Carl Zeiss Meditec) by the same surgeon. The initial 100 patients since the surgeon started operating independently were considered as group 1; the recent 100 patients were considered as group 2. The same laser settings and technique were used. The visual and refractive outcomes were compared between groups at postoperative 1 week and 6 months. Vector analysis was performed for eyes with astigmatic correction. RESULTS: Two hundred right eyes of 200 patients were included. Age, preoperative corrected visual acuity, manifest refraction, and central corneal thickness were similar between groups (P ≤ 0.154). Postoperatively, the efficacy index at 1 week was better in group 2 (group 1: 0.85 ± 0.16 vs. group 2: 0.91 ± 0.10, P = 0.019) but was similar between groups at 6 months (group 1: 0.91 ± 0.14 vs. group 2: 0.94 ± 0.08, P = 0.181). The safety index was higher in group 2 at 1 week (group 1: 0.93 ± 0.10 vs. group 2: 0.95 ± 0.08, P = 0.045) and 6 months postoperatively (group 1: 0.97 ± 0.07 vs. group 2: 0.99 ± 0.03, P = 0.011). Vector analysis showed that postoperative residual astigmatism and misalignment of astigmatic correction were lower in group 2 than in group 1 (P ≤ 0.039) at 1 week and 6 months. The duration of docking and that of lenticule extraction was shorter in group 2 (P ≤ 0.034). CONCLUSIONS: Our study showed that faster visual recovery, better safety profile, and more accurate astigmatic correction could be attained with increasing surgical experience.