Impact of crossplay between ocular aberrations and depth of focus in topo-guided laser-assisted in situ keratomileusis outcomes

Purpose: To develop a nomogram in cases with mismatch between subjective and Topolyzer cylinder, and based on the magnitude of the mismatch, customize a treatment plan to attain good visual outcomes post-laser-assisted in situ keratomileusis (LASIK) surgery. Methods: The patients were evaluated preoperatively using corneal tomography with Pentacam. Five optimal corneal topography scans were obtained from the Topolyzer Vario were used for planning the LASIK treatment. For the nomogram purpose, the patients were divided into three categories based on the difference between the subjective cylinder and Topolyzer (corneal) cylinder. The first group (group 1) consisted of eyes of patients, where the difference was less than or equal to 0.4 D. The second group (group 2) consisted of eyes, where the difference was more than 0.4 D and the subjective cylinder was lesser than the Topolyzer cylinder. The third group (group 3) included eyes where the difference was more than 0.4 D but the subjective cylinder was greater than the Topolyzer cylinder. LASIK was performed with the WaveLight FS 200 femtosecond laser and WaveLight EX500 excimer laser. Assessment of astigmatism correction for the three groups was done using Aplins vector analysis. For comparison of proportions, Chi-square test was used. A P value less than 0.05 was considered statistically significant. Results: The UDVA was statistically significantly different when compared between groups 1 and 2 (P = 0.02). However, the corrected distance visual acuity (CDVA) was similar among all the three groups (P = 0.1). Group 3 showed an increase of residual cylinder by −0.25 D, which was significant at intermediate and near reading distances (P < 0.05). Group 3 showed significantly higher target-induced astigmatism (TIA) compared to groups 1 and 2 (P = 0.01). The mean surgically induced astigmatism (SIA) was the least in group 2, which was statistically significant (P < 0.01). Conclusion: The outcomes for distance vision using our nomogram postoperatively were excellent, but further refinement for improving the near vision outcomes is required

Using adaptive optics to optimize the spherical aberration of eyes implanted with extended depth of focus and enhanced monofocal IOL

PURPOSE: To assess impact of change in ocular spherical aberration (SA) with adaptive optics on visual acuity at different defocus post implantation of extended depth of focus (EDOF) and enhanced monofocal intraocular lenses (IOL). SETTINGS: Narayana Nethralaya eye hospital, India. DESIGN: Prospective, longitudinal, observational. METHODS: Eighty eyes (40 patients), which had cataract surgery, were included in the study. Forty eyes were implanted with Eyhance EDOF IOL (Johnson and Johnson, USA) and the remaining with Vivity EDOF IOL (Alcon Laboratories Inc. USA). Baseline ocular aberrations were measured with Visual adaptive optics aberrometer (VOPTICA, Spain). Then, the optimal SA was determined by increasing it in steps of -0.01 µm up to -0.1 µm till the maximum improvement in near distance VA was observed for a given eye. Then, defocus curve for each eye was measured after modifying the ocular SA by magnitude equal to optimal SA. RESULTS: Most eyes accepted a negative induced SA of -0.05 µm (Eyhance group: 67.6%; Vivity group, 45.2%). In the Eyhance group (dominant eyes), VA improved at -2 D (p&lt;0.02) only, and degraded at 0 D, +0.5 D and +1 D defocus (p&lt;0.05). In the Vivity group, the VA remained unchanged at all defocus (p&gt;0.05). In the Eyhance group (non-dominant eyes), VA improved at -3.5 D defocus only, and degraded at +1.5 D and +2 D defocus (p&lt;0.05). In the Vivity group, a VA improved at -2.5 D defocus (p&lt;0.05) only. CONCLUSIONS: A negative induced SA of -0.05 µm in implanted eyes was optimal for a slight improvement in distance corrected near and intermediate VA without any significant decrease in baseline distance corrected VA

Artificial intelligence–based stratification of demographic, ocular surface high-risk factors in progression of keratoconus

Purpose: The purpose of this study was to identify and analyze the clinical and ocular surface risk factors influencing the progression of keratoconus (KC) using an artificial intelligence (AI) model. Methods: This was a prospective analysis in which 450 KC patients were included. We used the random forest (RF) classifier model from our previous study (which evaluated longitudinal changes in tomographic parameters to predict “progression” and “no progression”) to classify these patients. Clinical and ocular surface risk factors were determined through a questionnaire, which included presence of eye rubbing, duration of indoor activity, usage of lubricants and immunomodulator topical medications, duration of computer use, hormonal disturbances, use of hand sanitizers, immunoglobulin E (IgE), and vitamins D and B12 from blood investigations. An AI model was then built to assess whether these risk factors were linked to the future progression versus no progression of KC. The area under the curve (AUC) and other metrics were evaluated. Results: The tomographic AI model classified 322 eyes as progression and 128 eyes as no progression. Also, 76% of the cases that were classified as progression (from tomographic changes) were correctly predicted as progression and 67% of cases that were classified as no progression were predicted as no progression based on clinical risk factors at the first visit. IgE had the highest information gain, followed by presence of systemic allergies, vitamin D, and eye rubbing. The clinical risk factors AI model achieved an AUC of 0.812. Conclusion: This study demonstrated the importance of using AI for risk stratification and profiling of patients based on clinical risk factors, which could impact the progression in KC eyes and help manage them better

Phase retardation and corneal sublayer thickness repeatability using ultrahigh resolution polarization-sensitive OCT

PURPOSE: To assess phase retardation and corneal sublayer thickness repeatability using ultrahigh resolution polarization-sensitive OCT (PS-OCT).SETTING: Narayana Nethralaya eye hospital, Bangalore.DESIGN: ObservationalMethods: In this study, all eyes were imaged using our custom-built ultrahigh resolution PS-OCT and high-resolution hybrid OCT (MS-39, CSO, Italy). We evaluated the repeatability of phase retardation en face maps and corneal sublayer thickness profiles. The reflectivity and phase retardation were calculated from the two orthogonal polarization channels to generate en face maps of phase retardation and corneal sublayer thicknesses. Three consecutive measurements of all subjects were acquired for each eye. For each measurement, the subject was asked to sit back and was re-aligned again. The repeatability was assessed using intraclass correlation coefficient (ICC).RESULTS: The phase retardation en face maps showed preferential arrangement of collagen fibrils with least retardation in apex and maximum retardation in the periphery. The phase retardation showed excellent repeatability (ICC&gt;0.95) in all zones. The Bowman's layer and stromal layer thicknesses were measured with excellent repeatability (ICC&gt;0.93 and &gt;0.99, respectively). Significant differences (p&lt;0.05) in stromal layer thickness were observed between MS-39 and PS-OCT. The repeatability of epithelium thickness measurements was better with PS-OCT than MS-39.CONCLUSION: The combinational assessment of corneal birefringence and sublayer thicknesses shows the advanced potential of ultrahigh resolution PS-OCT in routine clinical practice over current OCT devices.</p

Status of Residual Refractive Error, Ocular Aberrations, and Accommodation After Myopic LASIK, SMILE, and TransPRK

PURPOSE: To analyze residual refractive error, ocular aberrations, and visual acuity (VA) during accommodation simultaneously with ocular aberrometry in eyes after laser-assisted in situ keratomileusis (LASIK), small incision lenticule extraction (SMILE), and transepithelial photorefractive keratectomy (TransPRK). METHODS: Ocular aberrometry (Tracey Technologies, Houston, TX) was performed 3 months after LASIK (n = 95), SMILE (n = 73), and TransPRK (n = 35). White measuring the aberrations, VA was measured at distance (20 ft), intermediate (60 cm), and near (40 cm) targets. The examinations were done monocularly. A parallel group of age-matched normal eyes (n = 50) with 20/20 Snellen distance VA also underwent aberrometry. RESULTS: Distribution of residual spherical error of LASIK eyes matched the normal eyes the best, followed by SMILE and TransPRK. However, the distribution of cylindrical error of the SMILE eyes was distinctly different from the rest (P <.05). The SMILE eyes tended to be undercorrected by approximately 0.25 diopters (D) on average at all reading targets compared to LASIK eyes (P <.05). The undercorrection was greater when the magnitude of the preoperative cylinder exceeded 0.75 D (P <.05). The VA of LASIK and SMILE eyes was similar to normal eyes at all targets, but the TransPRK eyes were marginally inferior (P <.05). Only the ocular defocus changed differentially between the study groups during accommodation and the magnitude of change was least for TransPRK eyes (P <.05). However, postoperative near and intermediate accommodation of LASIK eyes were similar to normal eyes, followed by SMILE eyes and then TransPRK eyes. CONCLUSIONS: The refractive and aberrometric status of the LASIK eyes was closest to the normal eyes. The SMILE procedure may benefit from slight overcorrection of the preoperative refractive cylinder

Status of Residual Refractive Error, Ocular Aberrations, and Accommodation After Myopic LASIK, SMILE, and TransPRK

PURPOSE: To analyze residual refractive error, ocular aberrations, and visual acuity (VA) during accommodation simultaneously with ocular aberrometry in eyes after laser-assisted in situ keratomileusis (LASIK), small incision lenticule extraction (SMILE), and transepithelial photorefractive keratectomy (TransPRK). METHODS: Ocular aberrometry (Tracey Technologies, Houston, TX) was performed 3 months after LASIK (n = 95), SMILE (n = 73), and TransPRK (n = 35). White measuring the aberrations, VA was measured at distance (20 ft), intermediate (60 cm), and near (40 cm) targets. The examinations were done monocularly. A parallel group of age-matched normal eyes (n = 50) with 20/20 Snellen distance VA also underwent aberrometry. RESULTS: Distribution of residual spherical error of LASIK eyes matched the normal eyes the best, followed by SMILE and TransPRK. However, the distribution of cylindrical error of the SMILE eyes was distinctly different from the rest (P <.05). The SMILE eyes tended to be undercorrected by approximately 0.25 diopters (D) on average at all reading targets compared to LASIK eyes (P <.05). The undercorrection was greater when the magnitude of the preoperative cylinder exceeded 0.75 D (P <.05). The VA of LASIK and SMILE eyes was similar to normal eyes at all targets, but the TransPRK eyes were marginally inferior (P <.05). Only the ocular defocus changed differentially between the study groups during accommodation and the magnitude of change was least for TransPRK eyes (P <.05). However, postoperative near and intermediate accommodation of LASIK eyes were similar to normal eyes, followed by SMILE eyes and then TransPRK eyes. CONCLUSIONS: The refractive and aberrometric status of the LASIK eyes was closest to the normal eyes. The SMILE procedure may benefit from slight overcorrection of the preoperative refractive cylinder