Journal of refractive surgery最新文献

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.

Purpose: To establish a diagnostic index for keratoconus based on spectral-domain optical coherence tomography (SD-OCT) and to compare it with existing parameters.

Methods: SD-OCT and Scheimpflug-based tomography were conducted on normal and keratoconic eyes. Multiple SD-OCT machine-derived parameters were assessed for the whole cornea, stroma, and epithelium. Receiver operating characteristic (ROC) curves were performed to determine area under the curve (AUC), sensitivity, and specificity. Principal component analysis and multinomial logistic regression after features selection established a new diagnostic index (Whole Information of Stroma and Epithelium [WISE]). The WISE index was compared with existing Scheimpflug-based diagnostic parameters.

Results: A total of 306 healthy control, 101 forme fruste keratoconus (FFKC), 86 early keratoconus (EKC), and 161 advanced keratoconus eyes were included for training and internal validation, as well as 52 normal, 31 FFKC, and 36 EKC eyes as a test dataset. The highest-ranked SD-OCT parameters to discriminate FFKC and EKC from normal eyes were Pachymetry_9mm_N (AUC = 0.65) and Epithelium_5mm_SN-IT (AUC = 0.77). In the internal validation and test datasets, the proposed WISE index demonstrated AUC = 0.76 and 0.83 for FFKC, and = 0.92 and 0.94 for EKC, respectively, comparable to Belin-Ambrósio Deviation and Pentacam Random Forest Index, as confirmed by De-Long's test (All P > .10).

Conclusions: Individual OCT-based machine-derived parameters lack sufficient power to discriminate FFKC and EKC from normal corneas, but this can be improved by combining OCT-based information from stroma and epithelium as in this new index. The discrimination accuracy of the WISE index was comparable to existing Scheimpflug-based indices.

Purpose: To explore the correlation between epithelial behavior markers derived from optical coherence tomography (OCT) and topographic inferior-superior asymmetry (I-S), and to compare these epithelial values across different I-S subgroups.

Methods: In this prospective observational study, 526 eyes undergoing refractive surgery evaluation were randomly selected. Each patient underwent imaging examinations, including Placido-disk corneal topography and OCT. Four epithelial parameters-minimum (thinnest), maximum (thickest), difference between minimum and maximum, and standard deviation-were analyzed. Analysis of variance and Kruskal-Wallis tests compared these parameters across I-S subgroups, whereas Pearson correlation assessed the relationship between continuous I-S values and each epithelial parameter. Multiple linear regression evaluated the I-S predictive effect on epithelial metrics. Correlations were investigated considering the entire I-S spectrum and in two separate I-S subgroups (below and above 1.4).

Results: Higher I-S values (I-S > 1.4) corresponded to significantly greater epithelial variability (difference between minimum and maximum, and standard deviation, P < .0001) compared to lower I-S groups. Across all I-S values, moderate, significant correlations were found between I-S and epithelial variability (difference, r = 0.57; standard deviation, r = 0.59; P < .0001). Subgroup analysis indicated that significant correlations between I-S and epithelial variability measures were present only in the high-asymmetry group (I-S > 1.4). Multiple linear regression confirmed that I-S significantly predicts epithelial variability, particularly in this subgroup.

Conclusions: A moderate correlation exists between I-S and epithelial thickness variability, particularly in eyes with high asymmetry, as supported by regression analysis, indicating the predictive value of I-S. However, these epithelial markers are less useful in eyes with low asymmetry.

Purpose: To review the reported outcomes for correction of astigmatism using excimer laser-based corneal refractive surgery techniques and to present distinctly the intricacies of the different ablation profiles.

Methods: Keywords such as "refractive correction," "excimer lasers," "ablation profiles," and "astigmatism" were used for literature research. Inclusion criteria were strict relevance and adequacy to the clinical questions under research, and availability of the abstract in the English language.

Results: Bitoric, cross-cylinder, and custom wavefront-optimized (aberration-neutral) or wavefront-guided treatments are used in modern laser systems to correct astigmatism. From scientific literature reviewed in this article, laser ablation to correct astigmatism was found to produce satisfactory visual outcomes in terms of safety, efficacy, and predictability. Custom ablation respecting postoperative corneal curvature gradient, correcting true corneal astigmatism after eliminating the higher order aberrations, and accurately compensating for possible cyclotorsion will result in patient satisfaction.

Conclusions: Integrating subjective and objective assessment of astigmatism effectively to optimize treatment outcomes is complex, particularly across a wide range of refractive errors. Properly determining how much astigmatism should be incorporated into the treatment is critical. Ignoring ocular residual astigmatism and sculpting the cornea based only on manifest refraction has the penalty that the entire ocular residual astigmatism remains as postoperative surgical residual astigmatism, also resulting in induction of spherical aberrations. Centration, optical zone sizes, cyclotorsion compensation, and use of appropriate treatment algorithms are of prime importance in obtaining favorable outcomes in correction of astigmatism.