Ray-tracing-guided myopic LASIK: real-world clinical outcomes.

PURPOSE: To assess effectiveness of individualized ray-trace based laser in situ keratomileusis (LASIK) for correction of myopia in everyday clinical practice. SETTING: Single-site private practice. DESIGN: Retrospective nonrandomised unmasked chart review. METHODS: Consecutive, myopic eyes (range ≤-8.25 diopters [D] sphere; astigmatism 0 to -4.25 D) treated with ray-trace based LASIK were included. Patients underwent wavefront, tomography, and biometry assessment using the InnovEyes Sightmap diagnostic device. The ray-trace based algorithm (InnovEyes algorithm) then generated an individualized 3D eye model and calculated a customized LASIK ablation profile. Postoperative visual acuity, refractive error and whole eye higher-order aberrations (HOAs) were evaluated over 3 months. RESULTS: The procedure was performed on 400 eyes (200 patients). Mean preoperative manifest refraction spherical equivalent was -3.39 ± 1.58 D (right eye -3.84 ± 1.63 D, left eye -3.98 ± 1.75 D). At month 3, uncorrected distance visual acuity (UDVA) was ≥20/20 in all eyes, ≥20/16 in 89% (right eye 90%, left eye 89%), ≥20/12 in 51% (54% right eye; 47% left eye), and 20/10 in 8% (right eye 8%; left eye 9%) of eyes respectively. UDVA was within 1 line of preoperative corrected distance visual acuity in 98% of eyes (right eye 98.5%; left eye 98%) and 39% of eyes (right eye 38%; left eye 39%) gained 1 line improvement. There was a statistically but not clinically significant increase in total HOAs (right eye 0.06 ± 0.133 µm; left eye 0.057 ± 0.125 µm; P < .001). The spherical aberration decreased (right eye -0.047 ± 0.095 µm, P < .001; left eye -0.051 ± 0.091 µm, P < .001). CONCLUSIONS: Ray-trace based LASIK was safe and effective for correction of myopia with and without astigmatism. Approximately, half the eyes achieved ≥20/12.5 UDVA and 8% achieved 20/10. There was no clinically significant increase in total whole eye HOAs.

Subjective patient-reported visual quality after small-incision lenticule extraction and its correlation to the objective one.

PURPOSE: The purpose of the study was to characterize the subjective visual quality and satisfaction following small-incision lenticule extraction (SMILE) and to identify its influential factors. SETTING: Peking University Third Hospital, Beijing, China. DESIGN: This was a retrospective observational study. METHODS: Patients who had simultaneous binocular SMILE for myopia and myopic astigmatism were included 6 months postoperatively, and the patient-reported outcome questionnaire was employed for the assessment of visual quality in real-life situations. Examinations with SIRIUS combined corneal topography and tomography were performed including the parameters of Strehl ratio (SR), corneal higher-order aberrations (HOAs) within 6.0-mm area, kappa angel, and thinnest corneal thickness. Decentration and effective optical zone (EOZ) were measured based on a tangential pre-post-operation difference map. Binary logistic regression analysis was performed for predictors of patient-reported visual quality. RESULTS: Clinical data from 97 cases were analyzed retrospectively. Overall satisfaction was 96.91% (94/97). Fluctuation in vision and glare is the most frequent and dominant visual symptoms. SR value increased non-significantly compared with preoperative (P> 0.05). A statistically significant (P < 0.05) increase in total HOAs, spherical aberration, and coma was noted. SR and HOAs were not correlated with the degree of visual symptoms (P > 0.05). No objective parameter was found to be associated with patient-reported visual quality after SMILE (P> 0.05). CONCLUSION: The high patient-reported satisfaction confirmed the ideal effect on visual quality following SMILE in real-life situations, though some objective optical performances were not satisfying. It is very tolerant toward patients' conditions and mild deviations, and this study did not find factors affecting visual performances.

Influence of the Reference Center on the Calculation of Corneal Higher Order Aberrations.

PURPOSE: To evaluate the differences in corneal wavefront measurements in myopic and hyperopic eyes when calculated using three different reference centers and explore possible influencing factors for such differences. METHODS: Corneal wavefront measurements were performed in myopic and hyperopic eyes using a GALILEI Placido Dual Scheimpflug Analyzer (Ziemer Ophthalmic Systems AG). Corneal higher order aberrations (HOAs), including total, vertical, and horizontal coma-like aberrations, spherical aberrations, and total corneal HOAs through a 6-mm pupil size, were calculated over three different reference center positions: pupil center, corneal vertex, and limbus to limbus. Values were then compared between the myopic and hyper-opic eyes, and correlations with kappa distance and spherical equivalent were tested. RESULTS: A significant decrease in the level of total corneal HOAs (-0.04 ± 0.05 and -0.12 ± 0.09), total corneal coma (-0.07 ± 0.09 and -0.18 ± 0.12), and horizontal coma (-0.07 ± 0.11 and -0.22 ± 0.11) in myopic and hyperopic eyes, respectively, was found when recalculating from pupil center to corneal vertex centration, whereas a significant increase in the same aberrations was observed from pupil center or corneal vertex to limbus to limbus. Significant correlations were found between the kappa distance and changes in total corneal HOAs, total corneal coma, and horizontal coma from the pupil center to the corneal vertex in both groups. CONCLUSIONS: Corneal vertex centration generated the lowest level of corneal wavefront error in both groups. The differences in corneal aberrations between the reference centers for calculation were highly correlated with the kappa distance in hyperopic eyes. [J Refract Surg. 2023;39(5):340-346.].

Higher-order aberrations and visual quality after incision lenticule extraction surgery with intraoperative angle kappa adjustments between small and large kappa patients: A 2-year follow-up.

Purpose: To evaluate the postoperative visual outcomes, that is, corneal higher-order aberrations (HOAs) and visual quality, of patients with an angle kappa greater than 0.30 mm who underwent angle kappa adjustment during small-incision lenticule extraction (SMILE) 2 years after surgery compared to eyes with an angle kappa less than 0.30 mm. Methods: This was a retrospective study and included 12 patients from October 2019 to December 2019 who underwent the SMILE procedure for correction of myopia and myopic astigmatism and had one eye with a large kappa angle and another eye with a small kappa angle. Twenty-four months after surgery, an optical quality analysis system (OQAS II; Visiometrics, Terrassa, Spain) was used to measure the modulation transfer function cutoff frequency (MTFcutoff), Strehl2D ratio, and objective scatter index (OSI). HOAs were measured with a Tracey iTrace Visual Function Analyzer (Tracey version 6.1.0; Tracey Technologies, Houston, TX, USA). Assessment of subjective visual quality was achieved using the quality of vision (QOV) questionnaire. Results: At 24 months postoperatively, the mean spherical equivalent (SE) refraction was - 0.32 ± 0.40 and - 0.31 ± 0.35 in the S-kappa group (kappa <0.3 mm) and the L-kappa group (kappa ≥0.3 mm), respectively (P > 0.05). The mean OSI was 0.73 ± 0.32 and 0.81 ± 0.47, respectively (P > 0.05). There was no significant difference in MTFcutoff and Strehl2D ratio between the two groups (P > 0.05). Total HOA, coma, spherical, trefoil, and secondary astigmatism were not significantly different (P > 0.05) between the two groups. Conclusion: Adjustment of angle kappa during SMILE helps reduce the decentration, results in less HOAs, and promotes visual quality. It provides a reliable method to optimize the treatment concentration in SMILE.

Changes in asphericity of anterior and posterior corneal surfaces for mild-moderate and high myopia after topography-guided FS-LASIK.

PURPOSE: To compare changes in asphericity of anterior and posterior corneal surfaces for different myopia patients after corneal topography-guided femtosecond-assisted laser in situ keratomileuses (FS-LASIK), and to analyze correlations between asphericity of corneal surfaces and preoperative spherical equivalence (SEQ). METHODS: In this prospective study, 59 patients who underwent corneal topography-guided FS-LASIK surgery were enrolled and divided into the mild-moderate myopia group (67 eyes) and the high myopia group (44 eyes). Postoperative follow-ups were performed at 1, 3, and 6 months. Postoperative changes in aspherical coefficient (Q values), corneal higher-order aberrations (HOAs), and spherical aberrations (Z40) were compared between the two groups. Relevance between Q value changes and SEQ, HOAs, and Z40 as well as between SEQ and changes of HOAs and Z40 was analyzed. RESULTS: There was a significant increase in Q values of the anterior (each diameter) and posterior (6-8 mm) corneal surface in both groups than before surgery (P < 0.001). Q values of corneal anterior (each diameter) and posterior (7-9 mm) surface in the high group were considerably larger than the mild-moderate group (P < 0.05). Corneal anterior surface HOAs and Z40 values in the high group largely exceeded those of the mild-moderate group (P < 0.001). The preoperative SEQ was linearly correlated with postoperative anterior Q change (ΔQ), HOAs change (ΔHOAs), and spherical aberration change (ΔZ40). CONCLUSION: The changes of corneal asphericity in patients with high myopia were greater than mild-moderate myopia, with more corneal HOAs and Z40 introduced when corneal topography-guided FS-LASIK was conducted.

Outcome comparison between wavefront-guided and wavefront-optimized photorefractive keratectomy: A systematic review and meta-analysis.

Photorefractive keratectomy (PRK) eye surgery is widely used for patients at risk for corneal ectasia to maintain an aspheric corneal shape. Wavefront-guided (WFG) ablation profile was designed to reduce pre-existing higher-order aberrations (HOA). We aimed to compare the corneal aberrations and visual outcomes between WFG and Wavefront Optimized (WFO) PRK in patients with myopia. Eight randomized clinical trials were included. We searched PubMed, Scopus, Web of Science and CENTRAL at March 2020, and updated the search in September 2020 using relevant keywords, The data were extracted and pooled as Mean Difference (MD) with a 95% Confidence Interval (CI), using Review Manager software (version 5.4). Pooled results showed no significance between Uncorrected Distance Visual Acuity (UDVA) and Corrected Distance Visual Acuity (CDVA) between both groups underwent WFG and WFO PPR after three months follow up (MD = -0.03; 95% CI: [-0.06, 0.00]; P = 0.07), (MD = -0.02; 95% CI: [-0.04, 0.01]; P = 0.22) respectively. Although, no significant difference between mean manifest cylinder after three and 12 months follow up, but the total MD for mean manifest cylinder difference was significantly lower with the WFG treatment method (MD = -0.12, (95% CI: [0.23:-0.01], P = 0.03). This shows a slight advantage of the WFG over the WFO method. The visual performance showed similarity and excellent refractive outcomes in both WFO and WFG PRK. No significant statistical differences between the two approaches. On further comparison, there was a slight advantage of the WFG over the WFO method.

Long-term changes in contrast-sensitivity, corneal topography and higher-order aberrations after upper eyelid blepharoplasty: A prospective interventional study.

PURPOSE: The aim of this study was to analyze the long-term changes in visual parameters, that is, contrast sensitivity (CS) and higher-order aberrations (HOAs), and corneal topography in the patients undergoing upper eyelid blepharoplasty (UEB) for dermatochalasis. METHODS: This was a prospective, single surgeon, intervention study including patients (≥40 years age) having severe dermatochalasis with a minimum post-UEB follow-up of 12 months. The preoperative readings of CS (using Pelli-Robson chart), HOAs (using WaveLight ALLEGRO analyzer), and corneal topography (using topographic modeling system-4, Tomey corporation) were noted and compared at 3, 6, and 12 postoperative months. RESULTS: We studied 30 patients (60 eyes) who underwent bilateral UEB. The majority of patients were females (n = 21,70%), and the mean age of patients was 56.53 ± 9.06 years. The preoperative and postoperative values of LogMAR visual acuity, log CS value, corneal topography measurements (K1, K2, cylinder value, and the axis), optical aberrations (total HOAs; third-order--trefoil & coma; four-order--spherical aberrations and secondary astigmatism, and tetrafoil) were compared. At 12 months, the mean CS value, the majority of HOAs, and corneal topography (only cylinder values) showed a stable, statistically significant difference in the postoperative period. CONCLUSION: The UEB may produce long-term, visually-beneficial, optical, and corneal changes. The patients undergoing cataract surgery aiming for spectacle independence may gain additional visual benefits with UEB.

Outcomes Comparison Between Wavefront-Optimized and Topography-Guided PRK in Contralateral Eyes With Myopia and Myopic Astigmatism.

PURPOSE: To compare clinical outcomes between topography-guided customized ablation treatment (TCAT) and wavefront-optimized (WFO) photorefractive keratectomy (PRK) in fellow eyes of myopic patients. METHODS: Forty-six eyes of 23 patients who underwent PRK were included. WFO ablation was performed in one eye (WFO group) and TCAT in the fellow eye (TCAT group). The customized treatment plan was based on the Topolyzer Vario topography system (Alcon Laboratories, Inc) data. The patients were observed for 12 months after the procedure. RESULTS: One year after the surgery, there was no significant difference in the manifest refraction spherical equivalent, sphere, or cylinder variables between the two groups (P > .05). In both groups, 96% of eyes achieved an uncorrected distance visual acuity of 20/20 or better at 12 months postoperatively. Accuracy, safety, and efficacy of the refractive and visual outcomes were similar in the two groups. The postoperative higher order aberrations magnitude was lower in the TCAT group, but this was not statistically significant (P > .05). During the 12-month follow-up, no patient described any symptoms related to glare, halos, or starbursts in either eye. Other postoperative complications, such as infection or cor-neal infiltrates, did not occur in either group. CONCLUSIONS: TCAT and WFO ablations provided similar outcomes after PRK for myopia and myopic astigmatism correction. There were no statistically significant differences in postoperative corneal wavefront analysis. [J Refract Surg. 2020;36(6):358-365.].

Spherical Aberration Customization to Extend the Depth of Focus With a Clinical Adaptive Optics Visual Simulator.

PURPOSE: To evaluate the use of the VAO adaptive optics visual simulator (Voptica SL, Murcia, Spain) for customization of spherical aberration to increase depth of focus. METHODS: Through-focus visual acuity with both high- and low-contrast letters from +1.00 to -3.00 diopters (D) was measured in 17 dilated eyes with three different induced amounts of spherical aberration for a 4.5-mm pupil diameter: control (0 µm), -0.15 µm, and -0.30 µm. RESULTS: The defocus curves followed the same behavior with both values of contrast, but the visual acuity was 0.2 logMAR lower with low contrast. The mean values of high-contrast logMAR visual acuity at far, intermediate (67 cm), and near (40 cm) were -0.10, 0.11, and 0.37 for control, 0.04, 0.00, and 0.15 for -0.15 µm, and 0.23, 0.00, and 0.06 for -0.30 µm conditions. The 95% confidence interval ranged from ±0.14 to ±0.45 logMAR and the middle 50% of the distribution was approximately 0.2 logMAR. CONCLUSIONS: Negative values of spherical aberration extend the depth of focus in different ways depending on each patient. The VAO is a new instrument that allows the visual customization of spherical aberration to enhance depth of focus. [J Refract Surg. 2020;36(4):223-229.].

One-Year Outcomes From a Prospective, Randomized, Eye-to-Eye Comparison of Wavefront-Guided and Wavefront-Optimized PRK in Myopia.

PURPOSE: To compare wavefront-guided (WFG) and wavefront-optimized (WFO) photorefractive keratectomy (PRK) in patients with myopia using objective and self-reported quality of vision outcomes. METHODS: A total of 40 eyes from 20 participants were prospectively randomized to receive WFG or WFO PRK with the WaveLight Allegretto Eye-Q 400-Hz excimer laser (Alcon Laboratories, Inc., Fort Worth, TX). The primary outcome measured was uncorrected distance visual acuity (UDVA) at 12 months postoperatively. Secondary outcome measures included corrected distance visual acuity (CDVA), less than 5% and less than 25% contrast visual acuity, changes in higher order aberrations (HOAs), and self-reported quality of vision. Patients completed a validated, Rasch-tested, linear-scaled 30-item questionnaire assessing the quality of vision and visual symptoms preoperatively and at each visit. RESULTS: There was no statistically significant difference (P > .05) between the WFG and WFO groups in the frequency of attaining a refractive error within ±0.25 diopters of emmetropia, achieving postoperative UDVA of 20/16 or better or 20/20 or better, losing one or two or more lines or maintaining their preoperative CDVA, or differences in UDVA, CDVA, low contrast acuity, or HOAs. None of the measured quality of vision parameters exhibited statistically significant differences between the groups preoperatively or at 12 months postoperatively (all P > .05). The WFG and WFO groups each showed significant improvement in multiple subjective measures compared to pretreatment values in the same eye. A total of 12.5% of patients preferred their WFG PRK eye, 31.25% preferred their WFO PRK eye, and 56.25% had no preference at 12 months postoperatively. CONCLUSIONS: WFG and WFO PRK using the Alcon Wave-Light Allegretto Eye-Q 400-Hz excimer laser platform provide similar results and self-reported visual symptoms in myopic eyes at 12 months postoperatively. [J Refract Surg. 2020;36(3):160-168.].

Corneal wavefront aberrations and subjective quality of vision after small incision lenticule extraction.

PURPOSE: To analyse in depth the associations between objectively measured corneal higher-order aberrations (HOAs) and subjectively perceived visual quality after small incision lenticule extraction (SMILE) as quantified with the standardized and clinically validated quality of vision (QOV) questionnaire. METHODS: This cross-sectional study included patients after bilateral simultaneous SMILE for the treatment of myopia and/or myopic astigmatism with plano target refraction. Scheimpflug imaging (Pentacam HR; Oculus Optikgeräte GmbH, Wetzlar, Germany) was used to objectively quantify corneal HOAs. The standardized and validated QOV questionnaire was employed to gauge patients' subjectively perceived visual quality regarding frequency, severity and bothering effect of visual disturbances. RESULTS: A total of 394 eyes of 197 patients with a mean age of 32.4 ± 7.7 years and a mean postoperative follow-up of 24.3 ± 14.1 months were included. SMILE induced a statistically significant (p < 0.001) increase in spherical aberration (0.074 ± 0.131 µm), coma (0.142 ± 0.179 µm), trefoil (0.018 ± 0.067 µm) as well as in total HOAs (0.191 ± 0.176 µm). Surgically induced and postoperative levels of HOA showed no correlation with the three QOV scores representative of overall visual symptom frequency, severity and bothering effect (all R2 values ≤ 0.016). In addition, the associations between specific visual symptoms (e.g. starburst) and singular HOA terms (e.g. haloes) were very weak (all Rho values ≤ 0.164). CONCLUSIONS: Small incision lenticule extraction induced significant amounts of corneal HOAs that, however, showed no clear relationships to patient-reported QOV or specific long-term visual symptoms.

Clinical Outcomes of Small Incision Lenticule Extraction in Myopia: Study of Vector Parameters and Corneal Aberrations.

PURPOSE: To investigate clinical outcomes of small incision lenticule extraction (SMILE) including vector parameters and corneal aberrations in myopic patients. METHODS: This retrospective, observational case series included 57 eyes (29 patients) that received treatment for myopia using SMILE. Visual acuity measurement, manifest refraction, slit-lamp examination, autokeratometry, corneal topography, and evaluation of corneal wavefront aberration were performed preoperatively and at 1 and 3 months after surgery. We analyzed the safety, efficacy, vector parameters, and corneal aberrations at 3 months after surgery. RESULTS: Preoperatively, mean manifest refraction spherical equivalent refraction was -4.94 ± 1.94 D (range, -8.25 to 0 diopters [D]), and the cylinder was -1.14 ± 0.82 D (range, -3 to 0 D). Mean manifest refraction spherical equivalent improved to -0.10 ± 0.23 D at 3 months postoperatively, when uncorrected distance visual acuity was 20 / 20 or better in 55 (96%) eyes. The linear regression model of target induced astigmatism vector versus surgically induced astigmatism vector exhibited slopes and coefficients (R²) of 0.9618 and 0.9748, respectively (y = 0.9618x + 0.0006, R² = 0.9748). While total corneal root mean square higher order aberrations, coma and trefoil showed statistically significant increase, spherical aberration did not show statistically significant change after SMILE. CONCLUSIONS: SMILE has proven to be effective and safe for correcting myopia and astigmatism. We showed that SMILE did not induce spherical aberrations. A small increase in postoperative corneal higher order aberration may be associated with increase in coma and trefoil.

An Alternative Wavefront Reconstruction Method for Human Eyes.

PURPOSE: To expand upon and clinically demonstrate the results of a new polynomial decomposition method. METHODS: To discuss the theoretical considerations comparing the qualitative and quantitative information produced by the Zernike coefficients and a new polynomial decomposition basis, in a comparative series of theoretical and clinical case studies. RESULTS: These comparative studies validate the novel polynomial basis that decomposes the wavefront, with clear segregation of the higher and lower aberrations. There is no artifactual reduction of some of the higher order aberration coefficients, providing a more clinically relevant retinal image quality prediction. CONCLUSIONS: Some of the inherent limitations of the Zernike polynomials in clinical ophthalmic applications can be solved by a novel set of polynomials forming an alternative higher order basis. The new basis provides a clear separation between modes containing lower order terms versus higher order terms and offers clinicians a more clinically realistic wavefront analysis. [J Refract Surg. 2020;36(2):74-81.].

HIGHER-ORDER ABERRATIONS IN EYES WITH SILICONE OIL TAMPONADE.

PURPOSE: To investigate the changes in higher-order aberrations (HOAs) after silicone oil removal and to evaluate their associations with visual acuity. METHODS: Fifty-nine eyes of 58 patients who underwent SO removal were included. Total, corneal, and internal optic HOAs, and best-corrected visual acuity were measured before and 1 month after SO removal, and changes were compared between phakic and pseudophakic eyes. RESULTS: Total ocular and internal optic HOAs decreased significantly after SO removal both in pseudophakic (n = 40, all P < 0.001) and phakic eyes (n = 19, P = 0.017, P = 0.004). Preoperative HOAs (P < 0.001) and changes in HOAs (P = 0.006) were greater in pseudophakic eyes than in phakic eyes. Best-corrected visual acuity was significantly improved after SO removal, from 20/105 to 20/78 (P < 0.001) in pseudophakic eyes, whereas there was no difference in phakic eyes (P = 0.714). Preoperative HOAs and the reduction in HOAs after SO removal were greater in best-corrected visual acuity-improved eyes than best-corrected visual acuity-unchanged eyes (P < 0.001). CONCLUSION: Silicone oil tamponade induced an increase in HOAs, and these increases were greater in pseudophakic eyes than in phakic eyes. Silicone oil may cause additional visual impairments because of HOAs, beyond those caused by retinal diseases, particularly in pseudophakic eyes.

One-year follow-up of changes in refraction and aberrations induced by corneal incision.

PURPOSE: To evaluate the surgically induced changes in refraction (sphere and astigmatism) and higher order aberrations by corneal incision for one year. SETTING: University Hospital "Virgen de la Arrixaca", Murcia, Spain. DESIGN: Retrospective interventional case series. METHODS: Corneal power, astigmatism and higher order aberrations (HOA) were calculated from corneal topography measured in 27 eyes prior to surgery and at 2 weeks, 1, 2, 3 and 6 months and 1 year following cataract surgery with 3.2-mm corneal incision. At every stage, optical changes were calculated as the difference between pre- and post-surgery data (in each follow-up) using the formulas of obliquely crossed cylinders for the refraction and Zernikes coefficients for HOA. RESULTS: At 2 weeks after surgery the mean corneal values of induced sphere, cylinder and the root mean square (RMS) of HOA were +0.54±0.27 D, -0.77±0.32 D and 0.15 microns respectively. These parameters decreased significantly (p-values between 0 and 0.01) at 3 months to +0.33±0.27 D sphere, -0.50±0.24 D cylinder and 0.10±0.05 microns HOA and were stable at the next follow-ups. Induced spherical equivalent was around zero at all visits. The changes in HOA were mainly due to trefoil aberration. CONCLUSIONS: Linear corneal incisions do not change the spherical power but can induce significant values of astigmatism and trefoil aberration in the cornea. However, these changes revert fully or partially to preoperative values by the third month after surgery and remain stable with time.

SMILE, Topography-Guided LASIK, and Wavefront-Guided LASIK: Review of Clinical Outcomes in Premarket Approval FDA Studies.

PURPOSE: To review clinical outcomes of the U.S. Food and Drug Administration premarket approval (PMA) studies of the three recently approved refractive surgery platforms for the correction of spherocylindrical myopia. METHODS: Clinical outcomes and vector analysis of astigmatism were reviewed and compared between wavefront-guided laser in situ keratomileusis (LASIK) (WFG group) (STAR S4 IR with iDesign aberrometer; Johnson & Johnson Vision Care, Inc., Santa Ana, CA), topography-guided LASIK (TOPO group) (Allegretto Wave Eye-Q laser; Alcon Laboratories, Inc., Fort Worth, TX), and small incision lenticule extraction (SMILE group) (VisuMax laser; Carl Zeiss Meditec AG, Jena, Germany). RESULTS: The number of eyes included was 304, 249, and 334 for the SMILE, TOPO, and WFG groups, respectively. The WFG group had the highest preoperative spherical equivalent refraction (-6.21 ± 2.78 diopters [D]), followed by the SMILE (-5.39 ± 2.30 D) and TOPO (-4.61 ± 2.43 D) groups. At 6 months postoperatively, 83.7%, 88.9%, and 82.6% of eyes in the SMILE, TOPO, and WFG groups, respectively, had uncorrected distance visual acuity (UDVA) of 20/20 or better. SMILE showed slower visual recovery at early postoperative examinations, whereas the WFG group had a decrease in UDVA over time due to refractive regression. The mean refractive cylinder changed from -1.53 ± 0.70 D preoperatively to -0.22 ± 0.33 D at 6 months postoperatively in the SMILE group, -1.19 ± 1.23 to -0.19 ± 0.30 D in the TOPO group, and -1.77 ± 1.65 to -0.33 ± 0.36 D in the WFG group. With all three procedures, undercorrection of refractive cylinder was seen with increasing attempted correction. CONCLUSIONS: All three procedures demonstrated excellent outcomes, considering differences in attempted correction between studies. No obvious superiority of one technique over the others was found in astigmatic correction. [J Refract Surg. 2019;35(11):690-698.].

Case Series: Slight Intraocular Lens Malpositioning as a Potential Cause of Vision Loss.

SIGNIFICANCE: The cases illustrate an insidious cause of decreased visual acuity after cataract surgery. PURPOSE: The purpose of this study was to identify cases of postoperative vision loss caused by slight intraocular lens (IOL) malpositioning after cataract surgery. CASE REPORTS: Three patients presented with visual acuity decreased after cataract surgery. Silt-lamp examination before mydriasis revealed no abnormalities in two of the patients; mild IOL inferonasal decentration was found by the trifocal IOL diffraction ring in the third patient. Manifest refraction of these patients showed remarkable astigmatism with low corneal astigmatism. After pupil dilation, slight IOL decentration and tilt were observed in all patients, which were further confirmed using the Scheimpflug imaging system. Wavefront aberrometry showed a high level of ocular higher-order aberrations, most of which were derived from intraocular aberrations. CONCLUSIONS: Inconspicuous IOL malpositioning is one of the reasons responsible for decreased vision acuity after cataract surgery, which may not be easily identified by slit-lamp examination. High astigmatism and ocular higher-order aberrations derived from malpositioned IOL can be important clues.

Comparison of higher order wavefront aberrations with four aberrometers.

Purpose: To evaluate the agreement of selected higher order aberration measurements between aberrometers based on three different wavefront technologies. Methods: Twenty-three eyes of 23 participants were compared between Zywave, OPD-Scan III, and iDesign aberrometers, for total ocular aberrations. Participants were between 19 and 69 years of age, and exclusion criteria were previous ocular surgery or trauma, contact lens wear within the preceding 2 weeks, and ocular or systemic disease. Corneal aberrations were compared between the OPD-Scan III and GALILEI™ G2 aberrometers. Zernike coefficients of vertical and oblique trefoil, vertical and horizontal coma, and spherical aberration were analyzed in R software. Results: In all, 276 scans were captured in total, with a male-to-female ratio of 11:12. Total ocular vertical coma [mean difference (MD) = 0.026 µm, P < 0.005], vertical trefoil (MD = 0.033 µm, P < 0.05), and spherical aberration (MD = 0.022 µm, P < 0.05) differed significantly between the iDesign and OPD-Scan III. Differences in total vertical (MD = 0.072 µm, P < 0.05) and oblique trefoil (MD = 0.058 µm, P < 0.05) were demonstrated between the Zywave and OPD-Scan III, and spherical aberration (MD = 0.030 µm, P < 0.005) between iDesign and Zywave. iDesign corneal horizontal coma (MD = 0.025 µm, P < 0.05) and spherical aberration (MD = 0.043 µm, P < 0.005) measurements were significantly different between the GALILEI™ G2 and the OPD-Scan III. Conclusion: Zywave, iDesign, and OPD-Scan III, and GALILEITM G2 and OPD-Scan III may be used interchangeably for their total ocular and corneal wavefront functions, respectively; however, care must be taken if using these devices for guiding ablation or monitoring corneal disease.

Topography-guided versus wavefront-optimized laser in situ keratomileusis for myopia: Surgical outcomes.

PURPOSE: To compare the outcomes of topography-guided and wavefront-optimized surgery in patients having laser in situ keratomileusis (LASIK) for myopia. SETTING: Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, and BALGEUN-EYE21 Operation Center, Gwangju, South Korea. DESIGN: Prospective case study. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Corneal higher-order aberrations measurements: Comparison between Scheimpflug and dual Scheimpflug-Placido technology in keratoconic eyes.

PURPOSE: To compare the difference and agreement of corneal higher-order aberrations (HOAs) in keratoconic eyes using Scheimpflug and dual Scheimpflug-Placido imaging systems. SETTING: Emory University, Atlanta, Georgia, and the University of Southern California, Los Angeles, California, USA. DESIGN: Retrospective between-devices reliability and agreement study. METHODS: Patients diagnosed with keratoconus were evaluated sequentially by Scheimpflug and dual Scheimpflug-Placido devices. 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. RESULTS: Fifty eyes from 50 patients (31 men, 19 women) were evaluated. Trefoil at 30 degrees, spherical aberration, and total RMS were significantly different between groups (P < .05), whereas trefoil at 0 degrees and total coma values were not statistically different. There was a weak positive correlation between devices for trefoil at 0 degrees (r = 0.228), and a moderate positive correlation for trefoil at 30 degrees (r = 0.473), horizontal coma (r = 0.430), and for total corneal RMS (r = 0.637). Vertical coma (r = 0.816) and spherical aberration (r = 0.874) showed a strong positive correlation. The 95% limits of agreement (LoA) for absolute values were 1.963 µm for trefoil at 30 degrees, 2.449 µm for trefoil at 0 degrees, 3.530 µm for horizontal coma, 2.145 µm for vertical coma, 1.242 µm for spherical aberration, and 10.527 µm for RMS. CONCLUSION: Significant differences were found between measurements of corneal HOAs generated by Scheimpflug and dual Scheimpflug-Placido devices in patients with keratoconus, with generally limited correlations and wide LoA. HOAs measurements from these devices should not be considered equivalent.