Journal of refractive surgery最新文献

Purpose: To determine the magnitude of higher order aberrations (HOAs) induced from light delivery device treatments after implantation of a light adjustable lens (LAL; RxSight).

Methods: Patients who underwent cataract surgery or refractive lens exchange with LAL implantation in a private practice were included in this retrospective, consecutive chart review. The iTrace (Tracey Technologies) was used to measure corneal, internal, and total HOAs before each adjustment and lock-in visit at a 3-mm entrance pupil size. HOAs were also measured after the final lock-in visit. Overall and individual HOAs that were induced throughout the course of the LAL treatments were measured. Subgroup analysis was performed analyzing number of adjustments, distance versus near target, spherical aberration induced, target proximity, and history of refractive surgery.

Results: This study included 56 eyes from 32 patients. The mean induction of total HOAs (combined corneal and internal aberrations) was -0.005 μm (standard deviation = 0.071). No induced total HOAs were greater than 0.3 μm. The 32 eyes that had undergone prior refractive surgery were found to have a statistically significant increase in induced HOAs compared to the 24 eyes without prior refractive surgery (P = .02). No other statistically significant differences were detected during subgroup analysis.

Conclusions: This study suggests that LAL treatments do not induce a clinically significant amount of HOAs. However, eyes that have previously undergone refractive surgery may be more likely to have a greater magnitude of HOAs induced by light delivery device treatments.

Purpose: To develop a machine learning model for identifying eyes with previous myopic laser vision correction (LVC).

Methods: A total of 41,508 (35,269 eyes in 20,399 patients) and 5,517 (5,517 eyes in 3,210 patients) examinations performed at Seoul National University Bundang Hospital (SNUBH) and Seoul National University Hospital (SNUH), respectively, were included in this study. Using the SNUBH dataset, a machine learning model for identifying eyes with previous myopic LVC (ML-LVC) was developed. The SNUBH and SNUH datasets, respectively, were used as internal and external validation sets to investigate the performance of the ML-LVC model and to compare it with that of the Cooke-Riaz-Wendelstein (CRW1) index.

Results: The areas under the receiver operating curve of the ML-LVC model were 0.9970 (95% confidence interval [CI]: 0.9957 to 0.9981) and 0.9960 (95% CI: 0.9929 to 0.9982) in the internal and external validation sets, respectively. The accuracies of the ML-LVC model were 0.9908 (95% CI: 0.9886 to 0.9929) and 0.9927 (95% CI: 0.9906 to 0.9949) in the internal and external validation sets, respectively. The sensitivities of the ML-LVC model were 0.9528 (95% CI: 0.9342 to 0.9691) and 0.9222 (95% CI: 0.8802 to 0.9600) in the internal and external validation sets, respectively. The ML-LVC model exhibited significantly better prediction results, compared with the CRW1 index, in both the internal and external validation sets (McNemar's test, P = .004, P = .005, respectively).

Conclusions: The ML-LVC model showed better performance in identifying eyes with myopic LVC, compared with the CRW1 index. This model will benefit many ophthalmologists and is currently available on a web application.

Purpose: To investigate the ultrastructure and apoptosis of small incision lenticule extraction (SMILE) lenticules under different preservation conditions.

Methods: A total of 104 corneal stromal lenticules of 52 patients (13 men and 39 women, age 28.85 ± 6.45 years, mean spherical error -4.27 ± 1.34 diopters [D]) were collected from small incision lenticule extraction (SMILE) surgeries, and were immediately preserved using glycerol, silicone oil, Optisol (Bausch & Lomb), and cryopreservation for 1 day, 1 week, and 1 month. Fresh lenticules were taken as control groups. Hematoxylin-eosin (HE) staining and transmission electron microscopy (TEM) were applied for evaluation of ultrastructure and terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) for cell apoptosis ratio. Changes of quantity of collagen in TEM were evaluated in each group among all time points.

Results: HE staining showed that collagen in the fresh lenticules had an orderly arrangement with few vacuoles. In each preservation group, vacuoles and changes in arrangement of collagen were observed. TEM showed that the mean density of collagen was lowest at 1 month in the glycerol, silicone oil, and cryopreservation groups and highest at 1 month in the Optisol group. Quantities of collagen of lenticules preserved for 1 day and 1 week in the Optisol group were not statistically significantly different from those in the fresh group. At the same storage time, the mean density of collagen was the highest in the cryopreservation group at 1 day and the Optisol group at 1 month, and there was no statistically significant difference among the other groups. There was no statistically significant difference in apoptotic cell ratio among groups.

Conclusions: SMILE lenticules preserved using glycerol, silicone oil, Optisol, and cryopreservation within 1 month maintain a similar cell viability level as fresh lenticules.

Purpose: To compare corneal deflection characteristics during air-puff before and after keratorefractive procedures using a mathematical method.

Methods: The authors collected Corvis ST (Oculus Optikgeräte GmbH) corneal images from 86 eyes after photorefractive keratectomy (PRK), 93 eyes after laser in situ keratomileusis (LASIK), and 76 eyes after small incision lenticule extraction (SMILE). Using these images, corneal deflection was quantified and modal coefficients obtained over time through a decomposition method. The results were then compared among individual patients to identify differences before and after surgery.

Results: SMILE surgery increased corneal deflection by a quantifiable amount with less dependence on the depth of removed tissue, demonstrating up to 1.46 times (maximum) greater modal deflection changes compared with other surgeries. In contrast, in PRK and LASIK, corneal deflection was increased with greater ablation depth. Inter-patient variability was the largest in PRK, particularly in lower-order modes, which affected a large central area. Higher-order modes of the decomposition method in the central area demonstrated that SMILE and PRK exhibited similar patterns before air-puff, whereas SMILE and LASIK exhibited similar deflection patterns during air-puff. A significant difference between LASIK and SMILE was observed in transient deflection during the early air-puff phase and the ending phase.

Conclusions: This computational method could comprehensively analyze the overall corneal bending over time. The results suggest the use of LASIK and PRK for patients with low myopia and SMILE for patients with high myopia.

Purpose: To evaluate the long-term efficacy of accelerated corneal cross-linking (A-CXL) in halting the progression of recurrence of keratoconus in the graft.

Methods: This was a retrospective chart review of patients who underwent A-CXL for recurrence of keratoconus between January 2017 and December 2018. Results of eye evaluations performed up to 4 years after A-CXL included slit-lamp examination, corneal tomography and biomechanics, binocular corrected distance visual acuity (CDVA), and the manifest refraction equivalent sphere. The efficacy of A-CXL was assessed with reference to thinnest corneal thickness (TCT), mean anterior axial radius curvature in corneal periphery (ARC), and posterior axial radius curvature (PRC) tomography data indicating the stability of the ectasia.

Results: Data from 25 eyes were collected. Significant worsening in TCT, ARC, PCR, maximum keratometry, posterior eccentricity, and CDVA (P = .01) were found before A-CXL. At 4 years of follow-up, no changes in all tomographic parameters and significant improvement in CDVA (P = .02) and in corneal biomechanics (stiffness parameter A1, deformation amplitude ratio highest, inverse concave radius, and appla-nation 2 velocity; P = .01) were found. None of the included eyes developed postoperative complications or required re-grafting or refractive procedures.

Conclusions: A-CXL is a safe procedure that could play a role in preventing graft ectatic changes in patients with recurrence of keratoconus after keratoplasty, strengthening the graft and halting the natural progression of the ectasia, with positive effects in improving CDVA.

Purpose: To assess visual, refractive, and optical outcomes and patient-reported satisfaction following bilateral implantation of two trifocal intraocular lenses (IOLs) sharing the same optical architecture but differing in their photopic light distribution: Vivinex Gemetric and Vivinex Gemetric Plus (HOYA Surgical Optics).

Methods: This was an observational, prospective, consecutive, non-comparative case series. Fifty-four eyes of 27 patients underwent bilateral cataract surgery or refractive lens exchange. Each patient received the Gemetric IOL in the dominant eye and the Gemetric Plus in the non-dominant eye. Examinations included full refractive and visual assessment, defocus curves, mesopic contrast sensitivity, pyramidal aberrometry, and validated patient-reported outcome measures (Quality of Vision Questionnaire and Near Activity Visual Questionnaire), with follow-up at 1 day and 1, 3, and 6 months.

Results: The paired IOL combination provided a visual acuity of 0.15 logarithm of the minimum angle of resolution (logMAR) or better between defocus levels of +0.50 to -3.00 diopters (D). Maximum mean value of visual acuity was obtained at 0.00 D (-0.07 ± 0.05 logMAR) and a second peak was found at -3.00 D (0.07 ± 0.09 logMAR). It was 0.13 ± 0.10 logMAR at a defocus level of -1.50 D. Monocular corrected near visual acuity was significantly better for the Gemetric Plus IOL (P = .03). Better monocular distance visual function was obtained with the Gemetric IOL (P = .05). Contrast sensitivity remained within or above age-matched normative values. Ocular aberrations remained low and stable, with no significant differences between lens types. Ninety-six percent of patients reported no or minor difficulties in conducting prolonged near work.

Conclusions: The pairing strategy of the Vivinex Gemetric and Gemetric Plus trifocal IOLs delivers excellent visual acuity across all distances, preserves contrast sensitivity, and maintains a high level of optical quality and patient satisfaction.

Purpose: To investigate the biomechanical effects of photorefractive keratectomy (PRK), laser in situ keratomileusis (LASIK), and keratorefractive lenticule extraction (KLEx) on postoperative corneal biomechanics and visual outcomes using patient-specific finite element simulations.

Methods: A cohort of 30 patients (24 ± 4 years) undergoing PRK, LASIK, or KLEx was modeled using finite element simulations. Patient-specific preoperative topographies informed the creation of surgical models with ablation and lenticule profiles tailored to the correction needs of each patient based on the same theoretical ablation profile across the three refractive procedures. The parameters of the mechanical model were calibrated using experimental data from human corneal tissue.

Results: Simulations showed a consistent undercorrection of the refractive targets for all procedures, which increased with higher spherical corrections. PRK showed the lowest undercorrection, followed by LASIK and KLEx. Procedure-specific correction factors were calculated to compensate for the biomechanical response and achieve the correction required for the patient: the spherical component should be multiplied by 1.40 for PRK, 1.57 for LASIK, and 1.71 for KLEx. Stress analysis revealed that PRK maintained a uniform anterior stress distribution (28% increase from preoperatively), whereas LASIK (53% increase from preoperatively) and KLEx (44% increase from preoperatively) concentrated stress in the posterior stroma.

Conclusions: Although the same volume of tissue was removed in all procedures, corneal biomechanics influence refractive surgery outcomes, with PRK offering advantages in terms of reduced undercorrection and more favorable stress distribution. PRK's conservative approach offers a greater biomechanical safety margin, making it the recommended option for suspiciously weak corneas.