Journal of refractive surgery最新文献

Purpose: To evaluate tilt, decentration, and axial stability of the Clareon toric intraocular lens (TIOL) (CNW0T3-9; Alcon Laboratories, Inc) over a 6-month follow-up period.

Methods: A single-center, prospective, interventional clinical trial was conducted with a study population of 130 eyes from 82 patients who received a Clareon TIOL. Tilt, decentration, and the aqueous depth were determined preoperatively and at 1 week and 6 months postoperatively using anterior segment optical coherence tomography (Casia 2; Tomey Corporation). Difference vectors were used to assess changes in individual decentration and tilt. Uncorrected intermediate visual acuity was measured at 66 cm at 6 months postoperatively.

Results: Mean tilt and decentration values were 5.7 ± 1.7° and 0.17 ± 0.1 mm for the crystalline lens, 5.6 ± 1.5° and 0.24 ± 0.13 mm for the TIOL at 1 week, and 5.8° ± 1.6° and 0.24 ± 0.15 mm for the TIOL at 6 months. Mean changes in tilt and decentration from preoperatively to 6 months were 1.01 ± 0.86° and 0.18 ± 0.12 mm. Tilt and decentration correlated between the crystalline lens and TIOL at 6 months (r = 0.92; P < .01, r = 0.29; P < .01). A posterior axial shift of 0.023 ± 0.054 mm was observed between 1 week and 6 months. Mean binocular uncorrected intermediate visual acuity at 66 cm at 6 months postoperatively was 0.18 ± 0.13 logarithm of the minimum angle of resolution (20/30 Snellen).

Conclusions: Tilt and decentration of the Clareon TIOL were generally low and a strong correlation was found between crystalline lens tilt and TIOL tilt at 6 months.

Purpose: To report the refractive outcome of femtosecond laser-assisted lenticule intrastromal keratoplasty (LIKE) in correcting moderate to high hyperopia. Intraoperative effective optical zone (EOZ), centration offset, and postoperative higher order aberrations (HOAs) were analyzed to better understand factors affecting postoperative outcomes.

Methods: This was a prospective, consecutive case series study of LIKE for correcting hyperopia in one department from 2018 to 2023. Refraction, tomography, uncorrected and corrected distance visual acuity (UDVA/CDVA), EOZ, and decentration offset by an innovated method using semi-automated software (ImageJ; National Institutes of Health) were analyzed. Tomography measured the preoperative and postoperative refractive tomographic changes.

Results: In the 18 eyes (9 participants) that underwent LIKE for correcting moderate to high hyperopia, the attempted spherical equivalent (SEQ) was +6.22 ± 0.85 diopters (D). One year postoperatively, 61% of all eyes had UDVA better than or equal to preoperative CDVA. In 78% of all eyes, the SEQ was less than 1.00 D from the attempted value. Compared to the programmed optical zone, the EOZ obtained after LIKE was significantly smaller (6.42 ± 0.15 vs 5.24 ± 0.23, P < .001). This was comparable to mild to moderate hyperopic LASIK treatment. The percentage of optical zone reduction was 18 ± 3%. The centration offset of the EOZ generated by LIKE was 0.27 ± 0.15 mm, and 94% of eyes had decentration within 0.5 mm. The induction of vertical coma and spherical aberration after LIKE were significantly higher.

Conclusions: LIKE is a promising procedure to maintain stable refraction and keratometry in correcting moderate to high hyperopia with sufficient EOZ, and acceptable decentration and corneal HOAs.

Purpose: To use parametric numerical simulation to characterize and compare the differences in corneal biomechanical responses to laser in situ keratomileusis (LASIK) and keratorefractive lenticule extraction (KLEx) under various surgical settings.

Methods: The Finite Element Model was used in a parametric study to evaluate corneal biomechanical responses to LASIK and KLEx, considering variations in preoperative corneal thickness, corneal flap/cap thickness and diameter, refractive correction, and optical zone diameter. Surgery-induced stress, displacement, and interface contact pressure were compared between LASIK and KLEx using the Wilcoxon signed-rank test. Spearman correlation analysis explored the correlation of the biomechanical response differences between surgeries with various parameters.

Results: LASIK induced more stress reductions and displacements than KLEx in corneal flap/cap (P < .001). Both surgeries introduced a centralizing redistribution of stress and displacement in the stroma (ie, stress increased with outward stromal displacement at the center), and stress decreased with inward displacement in the periphery. Stromal stress and displacement were higher after LASIK than after KLEx (P < .001). Corneas after KLEx exhibited higher contact pressure than those after LASIK (P < .001). With the significant increase in preoperative corneal thickness, refractive correction, optical zone diameter, and decreased flap/cap thickness, the biomechanical differences between surgeries were notably reduced, with most Spearman correlation coefficients (|r|) being greater than 0.3 (eg, stress and displacement differences at the stromal center reduced by 36.69% and 82.17% from refractive correction of -1.00 to -9.00 diopters).

Conclusions: Finite element simulations indicate that KLEx may provide improved corneal stability compared to LASIK under comparable surgical conditions. However, this biomechanical advantage is not absolute and depends on multiple factors, including refractive correction magnitude, central corneal thickness, and flap or cap thickness. These findings suggest that as refractive correction increases, cap or flap thickness decreases, or central corneal thickness increases, the biomechanical differences between KLEx and LASIK diminish. In certain cases, KLEx may exhibit biomechanical risks comparable to LASIK. These results highlight the need for a personalized approach in refractive surgery planning, considering both biomechanical and surgical complexity factors.

Purpose: To investigate eye movement dynamics during excimer laser ablation, specifically femtosecond laser-assisted in situ keratomileusis (FS-LASIK), and compare movement patterns between the right eye (always operated on first) and the left eye (operated on second), analyzing direction, magnitude, and temporal changes.

Methods: A retrospective analysis was conducted on 92 eyes from 46 patients who underwent FS-LASIK with the SCHWIND AMARIS system (SCHWIND eye-tech-solutions). Eye-tracking data were collected to record horizontal and vertical directional movements; variability was assessed using standardized metrics. Temporal trends were analyzed using split-interval and correlation methods.

Results: Eye movement patterns revealed greater variability in the vertical direction (t-test [t] = -2.32, P = .02) than in the horizontal direction (t = -0.27, P = 0.79) for both eyes. The second eye showed more variability, particularly in the vertical direction, with earlier and more dynamic increases (correlation [r] = 0.20, slope 0.50, both P < .0005). Horizontal movements were initially reduced but gradually increased after 22 seconds (t = 2.02 for right eye, t = 2.09 for left eye, P = .04 for both). Vertical movements increased significantly after 13 seconds in the right eye (t = -2.06, P = .04) and 5 seconds in the left eye (t = -2.40, P = .02).

Conclusions: Eye movements during FS-LASIK exhibit dynamic variability, especially in the vertical direction. The second eye showed earlier, more pronounced movements as surgery progressed. These findings suggest the need to consider eye movement dynamics in surgical planning and system design.

Purpose: To evaluate axis-dependent visual and refractive outcomes of small incision lenticule extraction (SMILE) in patients with interocular astigmatic axis discordance.

Methods: Seventy-five patients (150 eyes) with interocular astigmatic axis discordance were included in the study. Based on interocular axis combinations, patients were stratified into three cohorts: with-the-rule (WTR)/against-the-rule (ATR) (n = 19), WTR/oblique astigmatism (OA) (n = 39), and ATR/OA (n = 17). Refractive outcomes, corneal topography, and corneal wavefront aberrations were analyzed preoperatively and at 1 and 6 months postoperatively. Vector analysis using the Alpins method compared astigmatic correction accuracy.

Results: At 6 months, no significant difference was observed in visual acuity or residual sphere or cylinder between axis among different groups. Although 84% of ATR eyes and 64% of OA eyes achieved residual astigmatism of 0.25 diopters (D) or less, compared to 47% and 38% of their contralateral WTR eyes. Vector analysis revealed a systematic undercorrect of correction indices (CI < 1.0) in WTR eyes, and a full correction in non-WTR eyes (ATR CI = 0.99 ± 0.50, OA CI = 1.00 ± 0.47). ATR eyes exhibited greater angle of error compared to the contralateral WTR eyes (P = .04). OA eyes demonstrated decreased Trefoil30° aberrations compared to the contralateral ATR eyes (P = .003).

Conclusions: SMILE exhibited axis-specific efficacy patterns, with predictable astigmatic correction achieved in ATR and OA eyes, whereas WTR eyes demonstrated systematic undercorrection. These findings highlight the clinical relevance of preoperative axis evaluation, particularly in patients with interocular discordance.

Purpose: To determine the accuracy of a new machine learning-based open-source IOL formula (PEARLS-DGS) in 100 patients who underwent uncomplicated cataract surgery and had a history of laser refractive surgery for myopic defects.

Methods: The setting for this retrospective study was HUMANITAS Research Hospital, Milan, Italy. Data from 100 patients with a history of photorefractive keratectomy or laser in situ keratomileusis were retrospectively analyzed to assess the accuracy of the formula. The primary outcome measures were absolute refractive prediction error, refractive prediction error, and cumulative distribution of absolute refractive prediction error within multiple thresholds. These parameters were estimated post-hoc using the Shammas, Haigis-L, Barrett True-K without history, ASCRS calculator average, EVO, Hoffer QST, and PEARL-DGS formulas. The cumulative distribution of the absolute refraction prediction error was analyzed and statistically tested.

Results: EVO 2.0 showed the lowest median absolute error (MedAE) of 0.36 diopters (D), followed by Hoffer QST (0.38 D) and PEARL-DGS (0.41 D). The cumulative distribution of the absolute refractive prediction error at ±0.50 D threshold showed the following ranking: Hoffer QST (0.65), PEARL-DGS (0.61), EVO 2.0 (0.60), Barrett-True-K (0.56), Haigis-L, ASCRS (0.52), and Shammas (0.45). A significant difference was recorded between Shammas and Hoffer QST only at this threshold (P < .05). Statistical differences could not be detected otherwise.

Conclusions: The new PEARL-DGS IOL formula demonstrated similar accuracy and comparability in median refractive prediction error to the other current formulas in eyes with a history of myopic laser vision correction. The cumulative distribution of refractive prediction error of the PEARLS-DGS performed well even compared to the Hoffer QST results.

Purpose: To evaluate intraocular lens (IOL) power calculation of a non-diffractive extended depth of focus (EDOF) IOL after myopic laser in situ keratomileusis (LASIK) without historical data.

Methods: In this consecutive case series, patients who had undergone lens surgery with implantation of a non-diffractive EDOF IOL after myopic laser in situ keratomileusis (LASIK) at the Department of Ophthalmology, University Hospital Frankfurt, Frankfurt, Germany, were included. Preoperative assessments included biometry and tomography using Scheimpflug technology (Pentacam; Oculus Optikgeräte GmbH). Seven IOL calculation formulas for use in eyes after myopic LASIK have been analyzed: Potvin-Hill-Shammas-PM, OKULIX ray-tracing, PEARL-DGS and PEARL-DGS with posterior radial curvature, Barrett True-K No History with measured and predicted posterior corneal astigmatism, Hoffer QST, and EVO 2.0. The last three formulas were additionally calculated using the European Society of Cataract and Refractive Surgery (ESCRS) online calculator. Spherical equivalent prediction errors were analyzed using an established online tool (Eyetemis).

Results: Thirty-four eyes of 34 patients were enrolled. Trueness of all formulas was high, with no significant difference from zero, except for OKULIX ray-tracing (-0.40 ± 0.60, P < .01). No statistically significant differences in accuracy were found, with more than 59% of eyes within ±0.50 diopters and more than 85% within ±1.00 diopters for all formulas. Similar results were found between the formulas included in the ESCRS calculator when using the recommended IOL constants or constants from the IOLcon database.

Conclusions: A comparison of ray-tracing with other IOL calculation formulas revealed no substantial advantage for the former, resulting in comparable outcomes. Using the ESCRS calculator yielded comparable good results.

Purpose: To report a case of acute and transient accommodative insufficiency after laser in situ keratomileusis (LASIK) due to coronavirus disease 2019 (COVID-19).

Methods: Case report and literature review.

Results: A 36-year-old man complained of acute blurred near vision 7 days after uneventful bilateral hyperopic LASIK, concurrent with the onset of COVID-19 infection. Examination revealed new-onset accommodative insufficiency, with binocular cross-cylinder test demonstrating an accommodative lag of +1.00 diopters (D) in both eyes. Pupillary and ocular motility findings were normal. The patient was prescribed low add multifocal contact lenses for temporary use. Six months postoperatively, accommodative lag resolved, accommodative function returned to baseline, and near vision returned to J1 uncorrected.

Conclusions: This report describes acute accommodative insufficiency as a complication of COVID-19, with spontaneous resolution over 6 months. Given the significant impact on refractive surgery outcomes, the authors recommend delaying elective procedures for at least 6 months after COVID-19, especially in patients presenting with unexplained postoperative near vision changes.

Purpose: To compare the visual and refractive outcomes of low versus high myopic correction using laser in situ keratomileusis (LASIK) surgery.

Methods: Patients who underwent myopic LASIK between January 2013 and December 2023 were included. Eyes were divided into two groups based on preoperative myopia severity: low (0.50 to 3.00 diopters [D]) and high (≥ 6.00 D). Adjustments were made to account for differences in baseline and intraoperative parameters.

Results: In this retrospective study, 12,074 eyes of 6,985 patients were included. Mean spherical equivalent (SEQ) was -6.84 D for high myopia and -2.02 D for low myopia. High myopia was found in 6.7% of patients (n = 813), demonstrating preoperative steeper corneas (maximum keratometry 44.49 vs 44.21 D, P < .001) and worse uncorrected and corrected distance visual acuity (UDVA and CDVA) (2 vs 0.77 logMAR, P < .001; 0.03 vs 0.02 logMAR, P < .001, respectively). Following LASIK, the high myopia group had worse UDVA (0.04 vs 0.01 logMAR, P < .001) and CDVA (0.03 vs 0.01 logMAR, P < .001), higher cylinder (-0.08 vs -0.05 D, P < .001), and SEQ (-0.12 vs -0.07 D, P = .015). Keratometry measurements were flatter in the high myopia group (average: 38.43 vs 41.83 D, P < .001). After accounting for differences in baseline and intraoperative parameters, all of the above-mentioned parameters remained statistically significant. High myopia was not associated with higher re-treatment rates (P = .27).

Conclusions: Although LASIK surgery yielded satisfactory short-term outcomes in both low and high myopia, high myopia showed slightly less favorable refractive results. However, overall results were clinically acceptable in both groups. Similar re-treatment rates may reflect patient satisfaction or variability in surgeons' thresholds for offering enhancement procedures.