Comparative visual outcomes of the first versus second eye following small-incision lenticule extraction (SMILE).

BACKGROUND: This study aimed to compare the visual outcomes of the first operated eyes with those of the second operated eyes following small-incision lenticule extraction (SMILE). METHODS: A total of 202 patients (404 eyes) underwent SMILE using the tear film mark centration method for myopia and myopic astigmatism correction. Baseline characteristics, objective optical quality, decentered displacement, induced corneal aberrations, and modulation transfer function (MTF) values were assessed. Linear regression analyzed the relationship between decentration and visual quality parameters, including corneal aberrations and MTF values. RESULTS: No significant difference was observed in objective visual quality, efficacy, and safety indexes between the two groups (all P > 0.05). The average decentered displacement for the first and second surgical eyes was 0.278 ± 0.17 mm and 0.315 ± 0.15 mm, respectively (P = 0.002). The horizontal coma in the first surgical eyes were notably lower than in the second (P = 0.000). MTF values at spatial frequencies of 5, 10, 15, and 20 cycles/degree (c/d) were higher in the first surgical eyes compared to the second (all P < 0.05). Linear regression indicated that high-order aberrations (HOAs), root mean square (RMS) coma, spherical aberration, horizontal coma, vertical coma, and eccentric displacement were all linearly correlated. Furthermore, MTF values exhibited a linear relationship with eccentric displacement across these spatial frequencies. CONCLUSIONS: There was no discernible difference in visual acuity, efficacy, or safety between the two operated eyes. Nonetheless, the first operated eyes exhibited reduced decentered displacement and demonstrated superior outcomes in terms of horizontal coma and MTF values compared to the second operated eyes following SMILE. The variations in visual quality parameters were linearly correlated with decentered displacement.

Visual Quality Assessment After FS-LASIK Using Customized Aspheric Ablation Profile for Age-Related Accommodation Deficiency Compensation.

PURPOSE: To evaluate clinical outcomes and visual quality 12 months after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) performed with the Custom-Q algorithm for correction of myopia with or without astigmatism and compensate for age-related accommodation deficiency. METHODS: Patients who had Custom-Q FS-LASIK for myopia and myopic astigmatism with age-related accommodation deficiency were included in this retrospective study. Distance, intermediate, and near visual acuities, objective and subjective refractions, Q-factor, corneal higher order aberrations (HOAs), accommodation function, defocus curve, contrast sensitivity, and a subjective questionnaire assessing visual quality were evaluated 12 months postoperatively. RESULTS: Clinical data of 43 cases were analyzed. The mean age was 42.02 ± 1.85 years (range: 40 to 48 years). At the 12-month follow-up visit, there were 43 (100%), 42 (97%), and 33 (77%) patients who achieved a binocular uncorrected distance, intermediate, and near visual acuity, respectively, better than 20/20 separately. Defocus curves revealed better distance vision in the dominant eyes, and the nondominant eyes performed better at intermediate and near vergence (P < .001). The Q-value and corneal spherical aberration coefficient were more positive in the dominant eyes than those in the nondominant eyes (P < .001). The accommodative amplitude and relative accommodation improved binocularly (P < .001). The questionnaire demonstrated high patient satisfaction with near vision, and no one reported having severe visual disturbance. CONCLUSIONS: For myopic patients with age-related accommodation deficiency, the Custom-Q algorithm proved to be an effective way to achieve acceptable near vision without compromising distance vision. [J Refract Surg. 2024;40(4):e245-e252.].

Suboptimal visual outcome after femto-LASIK ablation in a high myopic patient.

A 28-year-old nurse had an aberration-free femto-laser in situ keratomileusis (LASIK) performed for her myopia of -6.25 -0.50 × 096 and -6.75 -0.50 × 175 in the right and left eye, respectively. Corrected distance visual acuity (CDVA) preoperatively was 20/16. Preoperatively, there were no abnormalities on Scheimpflug imaging, and a pachymetry of 585 µm was measured in both eyes. Flap thickness was 115 µm. The patient was quite nervous during the surgery. Since the surgery, her uncorrected distance visual acuity (UDVA) and CDVA are suboptimal at 20/30 and 20/20 in the right eye, and 20/20 and 20/16 in the left eye. 3 months postoperatively, there is a stable manifest refraction of +0.25 -1.25 × 030 and +0.25 -0.00 × 0. The keratometric astigmatism in the Scheimpflug imaging is 1.2 diopter (D) × 114 and 0.4 D × 78 in the right and left eyes, respectively (FIgures 1 and 2). Thinnest pachymetry is 505 µm and 464 µm in the right and left eye, respectively. Her wavefront analysis shows refraction in a 6 mm zone of -0.99 -1.22 × 32 and -0.91 -0.36 × 136. The cycloplegic refraction is 1.25 -1.00 × 023 and +1.00 -0.25 × 006 (Figures 3 and 4). What is the cause of the suboptimal visual outcome in this case? What would be your treatment strategy to improve visual outcome?

The visual impact of higher-order aberrations in patients with pediatric blepharokeratoconjunctivitis.

PURPOSE: To analyze higher-order aberrations (HOAs) and their visual impact in a pediatric blepharokeratoconjunctivitis (PBKC) cohort compared with healthy controls. METHODS: Prospective case-control study of pediatric patients (≤ 16 years old). Subjects underwent wavefront aberrometry analysis to compare HOAs and their impact on visual quality. RESULTS: A total of 150 eyes from 76 patients were included in the analysis. The PBKC group consisted of 50 eyes and the control group of 100 healthy eyes. Mean age was 10.39 ± 3.81 years for the PBKC group and 10.80 ± 3.61 years for the controls. Mean corrected-distance visual acuity (CDVA) was 0.24 ± 0.21 logMAR in the PBKC group and 0.07 ± 0.1 in the controls (P < 0.001). Mean astigmatism was 1.6 ± 1.98D in the PBKC group vs. 0.67 ± 0.76D in the control group (P = 0.01). Mean RMS of HOAs was 1.05 ± 1.7mm in the PBKC group and 0.41 ± 0.18mm in the controls (P < 0.001). The mean modulation transfer function (MTF) in the PBKC group was significantly lower (16.37 ± 16.32) than controls (30.3 ± 23.57) (P < 0.001). Corneal leukomas, stromal vascularization, peripheral nummular subepithelial scars, and pannus formation are associated with increased HOAs. CONCLUSIONS: There was a significant increase in total HOAs of eyes with PBKC compared to healthy controls. Corneal opacity, vascularization, and scarring are associated with increased HOAs. The PBKC eye aberration profile: coma, secondary astigmatism, quadrafoil, and pentafoil, were associated with decreased CDVA and visual quality (PSF and MTF).

A Comprehensive Wavefront Assessment of Keratoconus Using an Integrated Scheimpflug Corneal Tomographer/Hartmann-Shack Wavefront Aberrometer.

OBJECTIVES: To characterize higher-order aberrations (HOAs) in different severities of keratoconus (KC) from the anterior and posterior corneal surfaces and whole eye using an integrated Scheimpflug corneal tomographer/Hartmann-Shack wavefront aberrometer. METHODS: This study included eyes with clinical KC, topographic KC (no clinical signs), fellow eyes with very asymmetric ectasia with normal topography and no clinical signs (VAE-NT), and control eyes. Corneal and ocular wavefront aberrations were obtained using an integrated Scheimpflug tomographer/Hartmann-Shack wavefront aberrometer. The diagnostic capability of distinguishing VAE-NT from the control was also tested. RESULTS: This study included 68 eyes with clinical KC, 44 with topographic KC, 26 with VAE-NT, and 45 controls. Clinical KC had significantly greater total HOAs and coma from the anterior and posterior corneal surfaces and whole eye than the other groups ( P <0.05). Although topographic KC had significantly greater values in all wavefront parameters than the control ( P <0.05), ocular and corneal HOAs did not differ between the VAE-NT and control groups. The coma from the anterior cornea in topographic KC was significantly greater than that in VAE-NT ( P <0.05); the coma from the posterior cornea and whole eye did not differ. Total HOAs from the anterior corneal surface exhibited the highest area under the receiver operating characteristic curve value of 0.774 (sensitivity, 73%; specificity, 78%). CONCLUSION: A comprehensive wavefront assessment can be used to quantitatively evaluate corneal and ocular HOAs across various severity of KC. Total HOAs from the anterior corneal surface exhibited the potential ability in distinguishing VAE-NT from the control eyes.

Characterization of postoperative LASIK ectasia features on higher-order aberration excimer ablation maps.

BACKGROUND: To characterize anterior corneal higher-order aberration (HOA) excimer ablation map patterns in postoperative LASIK ectasia (POE) and to examine correlations between newly identified corneal HOA ablation map features of POE and known topographic indices. METHODS: Prospective multicenter non-interventional descriptive study. A total of 28 eyes from 22 POE patients were enrolled. The postoperative HOA ablation map was derived from Topolyzer Vario corneal imaging at the time of POE diagnosis. Features that recurred were identified and then analyzed. Correlations to Orbscan indices were studied. RESULTS: An arrangement of two elliptical paracentral ablation islands, deep inferior and shallow superior, in direct mirror-like opposition to each other, were identified on all HOA maps. The paracentral islands were accompanied by peripheral ablation crescents. The deep paracentral inferior island 'hot spot' coincided with the topographical apical POE cone and was highly reproducible in angular position (249.3 ± 17.3°). There was significant variation in ablation depth (shallow superior island: 11.5 ± 6.9 µm and deep inferior island: 32.5 ± 18.8 µm). The superior crescents had high variability in depth (34.8 ± 18.9 µm). Strong correlations were found between the corneal irregularity index and the ablation depth difference between the deep and shallow paracentral islands (R = 0.96; P < 0.0001). CONCLUSION: The corneal HOA excimer ablation map revealed a recurring, distinct, easily recognizable pattern in POE eyes. Validated Orbscan POE indices and HOA ablation map islands showed a strong correlation. It is possible to extract useful information from the corneal HOA ablation map, potentially making it suitable for diagnosing and monitoring POE although more studies are needed.

Comparing Effective Optical Zones After Myopic Ablation Between LASIK, PRK, and SMILE With Correlation to Higher Order Aberrations.

PURPOSE: To explore size, decentration, and eccentricity of effective optical zones (EOZs) in laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE) and correlate them to higher order aberrations (HOAs). METHODS: This was a retrospective chart review of 188 eyes that underwent refractive surgery for compound myopia (61 LASIK, 84 PRK, 43 SMILE). EOZ measurements were determined using 1-year postoperative Pentacam (Oculus Optikgeräte GmbH) tangential difference maps. HOA data were measured using Pentacam wavefront aberration Zernike polynomials. Correlations between EOZs and HOAs were analyzed. RESULTS: The EOZs of LASIK and PRK are smaller than SMILE at 19.54 ± 1.44, 19.39 ± 1.66, and 22.18 ± 2.61 mm2, respectively (P < .001). No difference existed in absolute decentration from corneal vertex (P = .078) or pupil center (P = .131), but horizontal and vertical components differed significantly (P < .001). Smaller EOZ areas were correlated with greater spherical aberration induction (rLASIK = -0.378, rPRK = -0.555, rSMILE = -0.501) and total HOA induction in all groups. Absolute decentration from corneal vertex positively correlated with total HOA (rLASIK = 0.396, rPRK = 0.463, rSMILE = 0.399) and directional vertical coma induction negatively correlated with vertical decentration from the corneal vertex (rLASIK = -0.776, rPRK = -0.665, rSMILE = -0.576) in all groups. CONCLUSIONS: SMILE results in a larger EOZ than LASIK and PRK, and absolute decentration remains comparable regardless of surgical reference center, despite horizontal/vertical differences. Surgical planning to ensure adequate EOZ size and centration may reduce induction of HOAs, including spherical aberrations and vertical coma. [J Refract Surg. 2023;39(11):741-750.].

Corneal Higher Order Aberrations and Epithelial Remodeling With Femtosecond Laser-Assisted LASIK Topography-guided and Customized Asphericity Ablation in the Contralateral Eye: A Randomized, Double-Blind, Prospective Study.

PURPOSE: To evaluate refractive results, corneal higher order aberrations (HOAs), and epithelial remodeling in the preoperative and postoperative period of regular corneas that had topography-guided femtosecond laser-assisted laser in situ keratomileusis (LASIK) (Contoura WaveLight; Alcon Laboratories, Inc) and compare them with the contralateral eye that underwent ablation customized by asphericity (Custom-Q WaveLight; Alcon Laboratories, Inc) in myopic eyes with or without astigmatism. METHODS: A prospective, randomized, and double-blind study was conducted. Patients underwent preoperative and postoperative epithelial mapping and corneal tomography to assess the epithelial thickness map, HOAs of the corneal anterior surface, visual acuity, and refractive evaluation. RESULTS: This study enrolled 96 normal eyes of 48 patients. Uncorrected distance visual acuity of 20/20 or better was achieved in 97% of patients and gains in corrected distance visual acuity and effectiveness in correcting refractive astigmatism were similar in both techniques. Seventeen sectors of the corneal epithelium map were assessed by spectral-domain optical coherence tomography and no significant differences were found between techniques preoperatively and postoperatively (P > .05). HOA root mean square, coma Z3±1, trefoil Z3-3, and tissue consumption exhibited statistically significant between-technique differences (P < .05). CONCLUSIONS: The Contoura and Custom-Q techniques were similar with respect to refractive and visual outcomes after 3 months, as well as in epithelial remodeling. The Contoura provides lower postoperative HOA root mean square, coma Z3±1, and trefoil Z3-3 values, but the techniques showed no differences in the correction of the corneal astigmatic wavefront component and in the spherical aberration after 3 months. [J Refract Surg. 2023;39(11):751-758.].

Changes in relative peripheral refraction and optical quality in Chinese myopic patients after small incision lenticule extraction surgery.

PURPOSE: To observe changes in retinal refraction difference values (RDV) and aberrations after small incision lenticule extraction (SMILE) surgery and evaluate their correlations. METHODS: This study recruited 112 patients (112 eyes) who underwent SMILE for myopia. Participants were classified into the Low and Moderate Myopia group (LM, -0.50 to -6.0 D) and High Myopia group (HM, >-6.0 D) according to the central spherical equivalent (SE). RDVs in the five retinal eccentricities from 0° to 10°, 10° to 20°, 20° to 30°, 30° to 40°, and 40° to 53° are recorded as RDV-(0-10), RDV-(10-20), RDV-(20-30), RDV-(30-40), and RDV-(40-53), respectively; additionally, RDVs have four sectors, i.e., RDV-Superior (RDV-S), RDV-Inferior (RDV-I), RDV-Temporal (RDV-T), and RDV-Nasal (RDV-N). With a 3-month follow-up, changes in RDV (ΔRDV) and changes in aberrations [Δtrefoil, Δcoma, Δspherical aberration (SA), and Δtotal higher-order aberrations (HOA)] after surgery were recorded. RESULTS: No significant differences were observed in total RDV (TRDV), RDV-(0-53), RDV-S, RDV-I, RDV-N, trefoil, coma, and SA between the two groups before SMILE surgery. However, after SMILE, hyperopic defocus values [TRDV, RDV-(20-53), RDV-S, RDV-T, and RDV-N] in the LM group and hyperopic defocus values [TRDV, RDV-(20-53), RDV-S, and RDV-N] in the HM group were significantly lower at 3 months postoperatively than preoperatively, and the RDV-(40-53), RDV-S, and RDV-N were lower in the HM group than in the LM group. Aberrations [trefoil (vertical), coma, and HOA] in the LM group and aberrations (trefoil, coma, SA, and HOA) in the HM group were significantly higher at 3 months postoperatively than preoperatively, and the coma, trefoil(horizontal), SA, and HOA were higher in the HM group than in the LM group. In the multivariate analysis, ΔRDV-(40-53) was significantly correlated with ΔSA, and ΔRDV-T and ΔRDV-N were significantly correlated with Δcoma (horizontal). CONCLUSIONS: Our findings suggest that SMILE reduces retinal peripheral hyperopic defocus but introduces some higher-order aberrations, especially in people with high myopia refractive errors.

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.

Outcomes of toric intraocular lens realignment surgery done using slit-lamp method and wavefront aberrometry method.

Purpose: To compare the slit-lamp method and wavefront aberrometry method based on outcomes of toric realignment surgeries. Settings: Tertiary care ophthalmic hospital. Design: Retrospective study. Methods: This study included all eyes undergoing toric intraocular lens (TIOL) realignment surgery between January 2019 and December 2021 for which TIOL axis assessment by slit-lamp method and wavefront aberrometry method was available. Data were retrieved from electronic medical records, and we documented demographics, uncorrected visual acuity (UCVA), subjective refraction, and TIOL axis by slit-lamp and wavefront aberrometry methods on postoperative day 1 and day 14. In patients with misalignment, TIOL was realigned to the original position in group 1 (27 patients) and to an axis based on calculations provided by wavefront aberrometer in group 2 (25 patients). Post-realignment surgery, UCVA, subjective refraction, and TIOL axis by slit-lamp and wavefront aberrometry methods were assessed and analyzed. Results: We analyzed 52 eyes and found that the mean preoperative misalignment with the slit-lamp method (44.9° ±20.0°) and wavefront aberrometry (47.1° ±19.5°) was similar. The corresponding degrees of misalignment post-TIOL repositioning surgeries were 5.2° ±5.2° (slit-lamp method) and 4.7° ±5.1° (wavefront aberrometry) (P = 0.615). Both groups showed significant improvement in median log of minimum angle of resolution (logMAR) UCVA and reduction in median refractive cylinder. Conclusions: Slit-lamp method is as good as wavefront aberrometer method to assess TIOL axis. Toric realignment surgery is found to be safe, and realigning TIOL based on either slit-lamp method or wavefront aberrometer method equally improved UCVA and decreased residual refractive cylinder.

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.

Comparison of visual quality after SMILE correction of low-to-moderate myopia in different optical zones.

OBJECTIVE: To compare the effects of different optical zones for small-incision lenticule extraction (SMILE) on postoperative visual quality in low-to-moderate myopia. METHODS: This retrospective case-control study involved patients who underwent SMILE using two optical-zone diameters: 6.5 mm (50 patients, 100 eyes) and 6.8 mm (50 patients, 100 eyes). Uncorrected visual acuity (UCVA), best corrected visual acuity, spherical equivalent (SE), corneal higher-order aberrations (HOAs), and subjective visual-quality questionnaire scores were assessed. RESULTS: Postoperatively, UCVA and SE did not differ between the two groups (P > 0.05). In both groups, corneal HOAs, spherical aberration, and coma significantly increased at 1 and 3 months postoperatively (P < 0.05), while trefoil was unchanged after surgery (P > 0.05). Corneal HOAs, spherical aberration, and coma significantly differed between the groups at 1 and 3 months (P < 0.05), while trefoil did not (P > 0.05). Visual-quality scores were higher in the 6.8 mm group than in the 6.5 mm group at 1 month (P = 0.058), but not at 3 months (P > 0.05). In both groups, subjective scores significantly decreased at 1 month (P < 0.05) and gradually returned to the preoperative level at 3 months (P > 0.05). The subjective visual-quality scores were negatively and positively correlated with pupillary and optical-zone diameter, respectively (P < 0.05 for both). Objective visual-quality indicators (HOAs, spherical aberration, and coma) were negatively correlated with optical-zone diameter (P < 0.05) but not pupillary diameter (P > 0.05). CONCLUSION: SMILE in different optical zones effectively corrected low-to-moderate myopia. The larger the optical-zone diameter, the better the early postoperative visual quality.

First European results of a new refractive lenticular extraction procedure-SmartSight by SCHWIND eye-tech-solutions.

BACKGROUND: To evaluate vision 3 months after SmartSight lenticule extraction treatments. DESIGN: Case series. METHODS: This case series of patients were treated at Specialty Eye Hospital Svjetlost in Zagreb, Croatia. Sixty eyes of 31 patients consecutively treated with SmartSight lenticule extraction were assessed. The mean age of the patients was 33 ± 6 years (range 23-45 years) at the time of treatment with a mean spherical equivalent refraction of -5.10 ± 1.35 D and mean astigmatism of 0.46 ± 0.36 D. Monocular corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA) were assessed pre- and post-operatively. Ocular and corneal wavefront aberrations have been postoperatively compared to the preoperative baseline values. Changes in ocular wavefront refraction, as well as changes in keratometric readings are reported. RESULTS: At 3 months post-operatively, mean UDVA was 20/20 ± 2. Spherical equivalent showed a low myopic residual refraction of -0.37 ± 0.58 D with refractive astigmatism of 0.46 ± 0.26 D postoperatively. There was a slight improvement of 0.1 Snellen lines at 3-months follow-up. Compared to the preoperative status, ocular aberrations (at 6 mm diameter) did not change at 3 months follow-up; whereas corneal aberrations increased (+0.22 ± 0.21 µm for coma; +0.17 ± 0.19 µm for spherical aberration; and +0.32 ± 0.26 µm for HOA-RMS). The same correction was determined using changes in ocular wavefront refraction, as well as changes in keratometric readings. CONCLUSION: Lenticule extraction after SmartSight is safe and efficacious in the first 3 months postoperatively. The post-operative outcomes indicate improvements in vision.

Comparative analysis of outcomes following topography-guided laser in situ keratomileusis using manifest refraction versus a new topographic analysis algorithm.

Purpose: To compare the visual outcomes following topography-guided laser in situ keratomileusis (LASIK) treatment using manifest refraction versus a new topography analysis software. Methods: A prospective, randomized, observer-masked contralateral study was conducted in the refractive services of a tertiary eye care hospital in South India. Analysis of visual outcomes, corneal higher-order aberrations, and contrast sensitivity were performed at 3 months postoperative visit following uneventful topography-guided LASIK using the Wavelight EX500. One eye was treated with the Contoura platform using manifest refraction (Contoura), while the contralateral eye was treated using an ablation profile planned by the Phorcides Analytic Engine (Phorcides). Results: Sixty eyes of 30 patients were included in the study. At 3 months postoperative visit, the uncorrected distance visual acuity (UDVA) in the Contoura and Phorcides groups was logarithm of the minimal angle of resolution (logMAR) 0.04 ± 0.07 and logMAR 0.06 ± 0.1, respectively (P = 0.483). Postoperative manifest refractive spherical error (MRSE) was 0.12 ± 0.22 and - 0.06 ± 0.20 D in the Contoura and Phorcides groups, respectively (P = 0.338). Although higher number of eyes demonstrated a gain in one or more lines of corrected distance visual acuity (CDVA) in the Contoura group (16.6% vs. 6.6%), the difference was not statistically significant (P = 0.361). Vector analysis (Alpins criteria) for postoperative cylinder, contrast sensitivity measurement, and corneal higher-order aberration profile showed no significant difference between the two groups at 3 months postoperative visit (P = 0.213, 0.514, and 0.332, respectively). Conclusion: Quantitative and qualitative visual outcomes with the Phorcides Analytic Software were similar to the Contoura treatment using manifest refraction.

Effect of preoperative pupil offset on corneal higher-order aberrations after femtosecond laser-assisted in situ keratomileusis.

BACKGROUND: This study aimed to investigate the relationship between multiple higher-order aberrations (HOAs) subgroups and pupil offset, as well as to analyze the factors affecting postoperative corneal HOAs in patients with different degrees of refractive errors. METHODS: We enrolled 160 patients (316 eyes) aged ≥ 18 years who had undergone femtosecond laser-assisted in situ keratomileusis (FS-LASIK) treatment. Based on the relationship between the preoperative pupil offset and the postoperative ΔHOAs, all patients were divided into two groups: group I (pupil offset ≤ 0.20 mm) and group II (pupil offset > 0.20 mm). All of the eyes had low to high myopia with or without astigmatism (manifest refraction spherical equivalent (MRSE) < -10.00 D). Uncorrected distance visual acuity, corrected distance visual acuity, MRSE, pupil offset, central corneal thickness, corneal HOAs, vertical coma (Z3-1), horizontal coma (Z31), spherical aberration (Z40), trefoil 0° (Z33), and trefoil 30° (Z3-3) over a 6 mm diameter central corneal zone diameter were evaluated preoperatively and at 1 and 3 months postoperatively. RESULTS: Our result revealed significant differences in postoperative corneal total root mean square (RMS) HOAs, RMS vertical coma, RMS horizontal coma, RMS spherical aberration, and RMS trefoil 30° between group I and group II. ΔMRSE was found to be an effective factor for ΔRMS HOAs (R2 = 0.383), ΔRMS horizontal coma (R2 = 0.205), and ΔRMS spherical aberration (R2 = 0.397). In group II, multiple linear regression analysis revealed a significant correlation between preoperative pupillary offset and Δtotal RMS HOAs (R2 = 0.461), ΔRMS horizontal coma (R2 = 0.040), and ΔRMS trefoil 30°(R2 = 0.089). The ΔRMS vertical coma effect factor is the Y-component, and the factor influencing ΔRMS spherical aberration was ΔMRSE (R2 = 0.256). CONCLUSION: A small pupil offset was associated with a lower induction of postoperative corneal HOAs. Efforts to optimize centration are critical for improving surgical outcomes in patients with FS-LASIK.

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.].

Monochromatic ocular high-order aberrations in children and adolescents.

PURPOSE: To investigate the prevalence and repeatability of high-order aberrations (HOAs) from non-cyclopleged eyes in 1515 children and adolescents 2.5-18 years of age. METHODS: The Leipzig Research Centre for Civilization Diseases (LIFE)-Child study is a population-based, prospective, observational single-centre study that investigates the development of children and adolescents in Germany. Wavefront measurements were repeated three times in each eye of 1515 healthy subjects. Results were described by 36 Zernike coefficients for a 5 mm reference pupil diameter. Short-term repeatability is given for each coefficient. The impact on vision is described by the root mean squared (RMS) value of the HOA Zernike coefficients. RESULTS: High-order aberrations were dominated by five contributions. For 1004 right eyes: spherical aberration (c12 = 0.06 ± 0.07 µm), coma (c7 = 0.03 ± 0.09 µm, c8 = 0.03 ± 0.06 µm) and trefoil (c6 = -0.01 ± 0.07 µm, c9 = 0.008 ± 0.06 µm). The RMS value was 0.18 ± 0.06 µm. Modes higher than fourth order do not contribute clinically to the aberrations. HOAs show no clinically significant dependency with age. Instead, HOA values agree well with previous results on aberrations in adult eyes. Spherical aberration was highly correlated between the two eyes. Repeatability was worst for coma, 0.033 µm, due to variability in the alignment of the pupil centre. The left eye showed, on average, a 0.08 mm larger pupil diameter than the right eye (p < 0.02). CONCLUSIONS: Across the age span from 2.5 to 18 years, we see the same distribution of HOA as for adults. We established that only five Zernike coefficients, spherical aberration, coma and trefoil were of clinical significance in healthy eyes. A high correlation between the two eyes for spherical aberration suggests a common blueprint for each eye in any one subject.

Visual outcomes of early enhancement following small incision lenticule extraction versus laser in situ keratomileusis.

Purpose: To compare visual outcomes of early enhancement following small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK). Methods: Retrospective analysis of eyes (patients operated in the setting of a tertiary eye care hospital between 2014 and 2020) requiring early enhancement (within one year of primary surgery) was conducted. Stability of refractive error, corneal tomography, and anterior segment Optical Coherence Tomography (AS-OCT) for epithelial thickness was performed. The correction post regression was done using photorefractive keratectomy and flap lift in eyes, wherein the primary procedure was SMILE and LASIK, respectively. Pre- and post enhancement corrected and uncorrected distance visual acuity (CDVA and UDVA), mean refractive spherical equivalent (MRSE), and cylinder were analyzed. IBM SPSS statistical software. Results: In total, 6350 and 8176 eyes post SMILE and LASIK, respectively, were analyzed. Of these, 32 eyes of 26 patients (0.5%) post SMILE and 36 eyes of 32 patients (0.44%) post-LASIK required enhancement. Post enhancement (flap lift in LASIK, and PRK in SMILE group) UDVA was logMAR 0.02 ± 0.05 and 0.09 ± 0.16 (P = 0.009), respectively. There was no significant difference between the refractive sphere (P = 0.33) and MRSE (P = 0.09). In total, 62.5% of the eyes in the SMILE group and 80.5% in the LASIK group had a UDVA of 20/20 or better (P = 0.04). Conclusion: PRK post SMILE demonstrated comparable results to flap lift post LASIK and is a safe and effective approach for early enhancement post SMILE.

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.