Refractive and Vector Outcomes of SMILE Pro with the VISUMAX 800 for High Astigmatism

Enhanced predictability and axis precision of SMILE Pro, a retrospective analysis of myopic astigmatism correction.

SMILE Pro using the VISUMAX 800 femtosecond laser provides safe and predictable correction of myopic astigmatism with good axis alignment, however, the observed undercorrection in higher cylinders suggests that further optimization of astigmatic nomograms may improve refractive accuracy.

Comparative Vector Analysis of Astigmatic Changes After Small-incision Lenticule Extraction versus Femtosecond Laser In -situ Keratomileusis

Abstract Purpose To compare thevisual outcomes of small-incision lenticule extraction (SMILE) versus femtosecond laser in-situ keratomileusis (FS-LASIK) in eyes with myopia and high astigmatism. Methods This retrospective study was conducted at a tertiary eye hospital between January 2021 and December 2022. Data were collected from individuals with myopia up to - 10.00 diopters (D) and cylinder ≥ 2.50 D who underwent SMILE (VisuMax 500) or FS-LASIK (MEL 90) and completed a 3-month postoperative follow-up. Results A total of 170 eyes of 123 patients were included: 83 eyes (60 patients) underwent SMILE, and 87 eyes (63 patients) underwent FS-LASIK. The preoperative cylindrical refractive error was - 3.01 ± 0.61 D in the SMILE group and - 3.09 ± 0.66 D in the FS-LASIK group. At 3 months, there was no statistically significant difference in uncorrected visual acuity (UCVA) or manifest refraction spherical equivalent (SEQ) between the two groups (P = 0.26 and P = 0.88, respectively). In the SMILE group, 90.4% of eyes achieved an uncorrected distance visual acuity (UDVA) of 20/20 or better compared to 98.77% with a preoperative corrected distance visual acuity (CDVA) of 20/20 or better. In the FS-LASIK group, 80.46% of eyes achieved a UDVA of 20/20 or better compared to 94.25% with a preoperative CDVA of 20/20 or better. Moreover, 95.1% of eyes in the SMILE group and 94.3% in the FS-LASIK group were within ± 0.50 D. Vector analysis showed comparable results between the two groups in terms of target-induced astigmatism (P = 0.559), difference vector (P = 0.155), index of success (P = 0.091), and angle of error (P = 0.89). The surgically induced astigmatism and correction index were significantly lower in the SMILE group (P < 0.01), whereas the absolute magnitude of error was higher in the SMILE group (P = 0.02). Conclusion SMILE and FS-LASIK have comparable efficacy, predictability, and safety in correcting myopia associated with high astigmatism ( ≥ 2.50 D).

Early Visual, Refractive, and Astigmatism Vector Outcomes of StreamLight Trans-PRK for High Astigmatism (≥ 2.00 D)

Objective To report the early refractive, visual, and astigmatic-vector outcomes of single-step StreamLight™ transepithelial photorefractive keratectomy (Trans-PRK) on the WaveLight EX500 platform in eyes with high preoperative astigmatism (≥ 2.00 dioptres, D). Methods Single-centre cohort study of 171 consecutive eyes of 107 patients (mean age 27.87 ± 6.56 years; 37.4% female) treated by a single surgeon. Astigmatic outcomes were analyzed by the Alpins method at the corneal plane. A subset of 57 eyes with a mean follow-up of 10.3 ± 7.4 months underwent stability sub-analysis. Results Mean preoperative cylinder was 3.29 ± 0.81 D and mean spherical equivalent (SE) was −2.73 ± 2.56 D. At one month, mean UDVA was 0.05 ± 0.09 logMAR, mean residual cylinder was 0.65 ± 0.44 D, and mean SE was −0.22 ± 0.47 D. SE was within ±0.50 D of intended in 71.3% of eyes; cylinder was ≤ 0.50 D in 53.2%. Mean efficacy and safety indices were 1.04 ± 0.22 and 1.10 ± 0.22, respectively, with no eye losing two or more lines of CDVA. Vector analysis yielded a correction index of 1.09 ± 0.16, an index of success of 0.21 ± 0.14, and 99% of eyes within ±15° of the intended axis. Stability sub-analysis showed minimal change in SE and an unchanged cylinder between 1 month and a mean follow-up of 10.3 ± 7.4 months (SE −0.14 to −0.07 D). Discussion Trans-PRK delivered good early visual, refractive, and astigmatic vector outcomes. Axis precision was high with a mean angle of error of −0.81 ± 5.32°, 80% of eyes within ±5°, and 99% within ±15° of the intended axis. Interpretation of vectorial results is subject to the specificity of the 1-month post-Trans-PRK central epithelial thickness (CET decreases in the first week, returns to baseline at 1 month, and progressively increases up to 6 months). Conclusions Single-step StreamLight™ Trans-PRK on the WaveLight EX500 platform achieves favorable early refractive, visual, and vector-analytic outcomes in eyes with high preoperative astigmatism, with corneal-plane vector parameters that compare favorably with those reported in the published Trans-PRK literature.

Visual and Refractive Outcomes Across Low, Medium, and Large Cyclorotation Angles in Myopic LASIK With Automated Cyclorotation Compensation.

PURPOSE To evaluate visual and refractive outcomes across different cyclorotation magnitudes in myopic laser in situ keratomileusis (LASIK) using automated cyclorotation compensation. METHODS This retrospective comparative study included consecutive patients who underwent myopic LASIK between 2012 and 2023. Patients were divided into three groups according to their cyclorotation angle magnitude. A comparison of baseline and intraoperative parameters was performed. Refractive and visual outcomes were assessed, including efficacy and safety indices, and an Alpins vector analysis was performed. Multiple linear regression was used to identify the effect of potential confounders. RESULTS Overall, 6,920 eyes of 4,454 patients were included. The mean age was 30.7 ± 8.7 years and 47.7% (2,130) were women. Analysis indicated significant differences in corrected distance visual acuity between the groups, but post-hoc analysis revealed no significant pairwise differences. Other visual and refractive outcomes including the calculated indices showed no significant differences. Alpins vector analysis showed no significant differences between the groups in any of the vectors in either magnitude or direction, nor were there significant differences in the calculated indicators. Multiple linear regression suggested age, maximum ablation depth, rotation direction, preoperative axis, and treated axis had confounding effects mostly on Alpins vectors. However, no significant effect was noted for outcomes that showed significant differences. CONCLUSIONS Cyclorotational angle magnitude did not significantly impact visual or refractive outcomes in myopic LASIK when using modern laser devices. These findings suggest limited clinical relevance of cyclorotation degrees in LASIK outcomes, with other factors potentially playing a more significant role in surgical planning.

Safety and Efficacy of Keratorefractive Lenticule Extraction (KLEx) for High Myopia with the CLEAR Platform

Objectives: To assess the safety and efficacy of Keratorefractive Lenticule Extraction (KLEx) in patients with myopia ≥ 5 diopters (D). Methods: Retrospective study of KLEx procedures performed at Siena Eye Laser (Poggibonsi, Italy) with the CLEAR platform of the Ziemer Z8 femtosecond laser. Results: We included 137 eyes of 85 patients; mean age was 33.8 ± 8.3 years. Assessment at baseline showed a mean myopic error of −7.3 ± 1.4 D, a mean astigmatic error of 1.1 ± 0.8 D, and a mean spherical equivalent (SE) of −7.8 ± 1.6 D. Preoperative corrected distance visual acuity (CDVA) was 0.0 logMAR or better in all eyes. Mean corneal thickness was 510.0 ± 26.9 µm. At post-operative day 1 (POD1) uncorrected distance visual acuity (UDVA) was 0.1 ± 0.1 logMAR, with a mean residual SEQ of 0.1 ± 0.8 D. At 6 months follow-up, mean UDVA significantly increased to 0.0 ± 0.0 logMAR (p < 0.001), with a mean residual SE of −0.12 ± 0.7 D (p > 0.05 compared to POD1). At 24 months, the mean UDVA remained stable at 0.0 ± 0.0 logMAR, with a mean residual SE of −0.1 ± 0.4 D as manifest refraction (all p > 0.05 compared to 6 months). At 6 months and 2 years, the observed residual stromal bed (RSB) was 30 microns thicker than the RSB calculated by the Ziemer LDV Z8 software 2022. The difference between predicted (POZ) and effective (EOZ) optical zone correlated with the degree of myopia corrected (r = 0.6, p < 0.001). The difference between POZ and EOZ inversely correlated with astigmatic correction (r = −0.5, p < 0.001). Conclusions: In patients with high myopia, CLEAR showed good predictability and efficacy. Both UDVA and SE improved during the first 6 months, and remained stable at 2 years. The effective RSB was thicker than expected, and patients with high astigmatism achieved a larger EOZ.

Astigmatic vector outcomes after FS-LASIK versus SMILE for high myopic astigmatism: a single-center retrospective comparative cohort study without cyclotorsion compensation