Vector analysis of astigmatic changes after small-incision lenticule extraction and wavefront-guided laser in situ keratomileusis.

PURPOSE: To evaluate and compare the efficacy of the astigmatic correction after wavefront-guided laser in situ keratomileusis (LASIK) and small-incision lenticule extraction (SMILE) and in myopic eyes. DESIGN: Prospective case series. SETTING: Horus Vision Correction Center and Ellite Vision Correction Center, Alexandria, Egypt. METHODS: Myopic eyes with astigmatism up to 4.00 diopters (D) had wavefront-guided LASIK or small-incision lenticule extraction. Visual and refractive changes were evaluated during a 6-month follow-up. The astigmatic changes were evaluated using the Alpins method. RESULT: The study evaluated 107 eyes (55 patients), 52 eyes having wavefront-guided LASIK and 55 eyes, small-incision lenticule extraction. No statistically significant differences were found in the 6-month postoperative sphere between the 2 groups (P = .652). The postoperative manifest cylinder and spherical equivalent were significantly lower in the wavefront-guided LASIK group (P < .001). The 6-month postoperative cylinder was 0.50 D or less in all eyes in the wavefront-guided LASIK groups and in 79.8% in the small-incision lenticule extraction group (P < .001). Vector analysis showed a significantly higher difference vector (P < .001) and angle of error (P = .021) and a significantly lower correction index (P = .001) in the small-incision lenticule extraction group. The mean magnitude of error was -0.07 ± 0.20 (SD) and -0.20 ± 0.35 in the wavefront-guided LASIK group and small-incision lenticule extraction group, respectively (P = .012). CONCLUSION: Wavefront-guided LASIK and small-incision lenticule extraction were safe and effective for the correction of myopic astigmatism, although there was a trend toward undercorrection with small-incision lenticule extraction.

Comparative Analysis of the Clinical Outcomes of SMILE and Wavefront-Guided LASIK in Low and Moderate Myopia.

PURPOSE: To compare the clinical outcomes of small incision lenticule extraction (SMILE) and wavefront-guided LASIK (WFG LASIK) in eyes with low and moderate myopia. METHODS: This was a prospective, comparative study enrolling 110 eyes with low and moderate myopia (spherical equivalent ≤ 6.00 diopters [D]). Two groups were differentiated according to the surgical technique used: the WFG LASIK group included 51 eyes (51 patients) undergoing WFG LASIK using the STAR S4IR excimer laser and the iDesign aberrometer (Abbott Medical Optics, Abbott Park, IL) and the SMILE group included 59 eyes (59 patients) undergoing SMILE with the VisuMax platform (Carl Zeiss Meditec, Jena, Germany). Visual, refractive, aberrometric, and contrast sensitivity outcomes were evaluated during a 6-month follow-up. RESULTS: Mean efficacy index was 0.92 ± 0.11 and 1.12 ± 0.17 in the SMILE and WFG LASIK groups, respectively (P < .001). Postoperative spherical equivalent was within ±0.50 D in 81.54% and 98% of eyes in the SMILE and WFG LASIK groups (P < .001), and postoperative cylinder was 0.50 or below in 84.7% and 100% of eyes, respectively (P = .038). Mean safety index was 0.98 ± 0.08 and 1.20 ± 0.14 in the SMILE and WFG LASIK groups (P < .001), with losses of lines of corrected distance visual acuity in 6.8% and 0.0% of eyes, respectively. Higher increase in higher order (P < .001) and coma (P < .001) root mean square and higher decrease in contrast sensitivity for 6, 12, and 18 cycles/degree (P ≤ .001) were observed after SMILE. CONCLUSIONS: SMILE and WFG LASIK are efficacious and safe procedures for the correction of low and moderate myopia, but WFG LASIK allows a more predictable outcome and better aberrometric control. [J Refract Surg. 2017;33(5):298-304.].

Comparative analysis of the efficacy of astigmatic correction after wavefront-guided and wavefront-optimized LASIK in low and moderate myopic eyes.

AIM: To evaluate and compare the efficacy of the astigmatic correction achieved with laser in situ keratomileusis (LASIK) in eyes with myopic astigmatism using wavefront-guided (WFG) and wavefront-optimized (WFO) ablation profiles. METHODS: Prospective study included 221 eyes undergoing LASIK: 99 and 122 eyes with low and moderate myopic astigmatism (low and moderate myopia groups). Two subgroups were differentiated in each group according to the ablation profile: WFG subgroup, 109 eyes (45/64, low/moderate myopia groups) treated using the Advanced CustomVue platform (Abbott Medical Optics Inc.), and WFO subgroup, 112 eyes (54/58, low/moderate myopia groups) treated using the EX-500 platform (Alcon). Clinical outcomes were evaluated during a 6-month follow-up, including a vector analysis of astigmatic changes. RESULTS: Significantly better postoperative uncorrected visual acuity and efficacy index was found in the WFG subgroups of each group (P≤0.041). Postoperative spherical equivalent and cylinder were significantly higher in WFO subgroups (P≤0.003). In moderate myopia group, a higher percentage of eyes with a postoperative cylinder ≤0.25 D was found in the WFG subgroup (90.6% vs 65.5%, P=0.002). In low and moderate myopia groups, the difference vector was significantly higher in the WFO subgroup compared to WFG (P<0.001). In moderate myopia group, the magnitude (P=0.008) and angle of error (P<0.001) were also significantly higher in the WFO subgroup. Significantly less induction of high order aberrations were found with WFG treatments in both low and moderate myopia groups (P≤0.006). CONCLUSION: A more efficacious correction of myopic astigmatism providing a better visual outcome is achieved with WFG LASIK compared to WFO LASIK.

Wave Front-Guided Photorefractive Keratectomy Using a High-Resolution Aberrometer After Corneal Collagen Cross-Linking in Keratoconus.

PURPOSE: To evaluate the clinical outcomes of wave front-guided (WFG) photorefractive keratectomy (PRK) using a high-definition aberrometer in corneas with keratoconus at least 1 year after corneal collagen cross-linking (CXL). METHODS: Prospective uncontrolled interventional case series study including a total of 34 consecutive eyes of 25 patients with keratoconus previously treated with CXL. All cases underwent WFG PRK using the VISX STAR S4 IR excimer laser and the iDesign system. All eyes had keratoconus grade I or II according to the Amsler-Krumeich classification. Visual, refractive, and ocular aberrometric outcomes were evaluated during a 12-month follow-up. Astigmatic changes were analyzed with the Alpins vector method. RESULTS: A significant improvement was observed in the uncorrected and corrected distance visual acuities (P < 0.001). The mean efficacy and safety indices at 12 months postoperatively were 1.58 ± 1.11 and 1.96 ± 1.52, respectively. Manifest sphere and cylinder were reduced significantly (P < 0.001), with 76.5% of the eyes having a spherical equivalent within ±1.00 D at 12 months postoperatively. The mean difference vector and magnitude of error were 1.06 ± 0.92 and 0.43 ± 0.86 D, respectively. Some corneal irregularity indices were reduced significantly with surgery (P ≤ 0.005) as well as the level of ocular higher order aberrations, primary coma, and trefoil (P < 0.001). CONCLUSIONS: Sequential WFG PRK using the iDesign system and the STAR S4 IR excimer laser after CXL is an effective option to correct the spherocylindrical error and to minimize the level of higher order aberrations in mild and moderate keratoconus if the maximum intended ablation depth does not exceed 15% of the minimal corneal thickness.

Wavefront-Guided Laser Treatment Using a High-Resolution Aberrometer to Measure Irregular Corneas: A Pilot Study.

PURPOSE: To evaluate in a pilot study the visual, refractive, corneal topographic, and aberrometric changes after wavefront-guided LASIK or photorefractive keratectomy (PRK) using a high-resolution aberrometer to calculate the treatment for aberrated eyes. METHODS: Twenty aberrated eyes of 18 patients undergoing wavefront-guided LASIK or PRK using the VISX STARS4IR excimer laser and the iDesign aberrometer (Abbott Medical Optics, Inc., Santa Ana, CA) were enrolled in this prospective study. Three groups were differentiated: keratoconus post-CXL group including 11 keratoconic eyes (10 patients), post-LASIK group including 5 eyes (5 patients) with previous decentered LASIK treatments, and post-RK group including 4 eyes (3 patients) with previous radial keratotomy. Visual, refractive, contrast sensitivity, corneal topographic, and ocular aberrometric changes were evaluated during a 6-month follow-up. RESULTS: An improvement in uncorrected (UDVA) and corrected visual acuity (CDVA) associated with a reduction in the spherical equivalent was observed in the three groups, but was only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). All eyes gained one or more lines of CDVA after surgery. Improvements in contrast sensitivity were observed in the three groups, but they were only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). Regarding aberrations, a reduction was observed in trefoil aberrations in the keratoconus post-CXL group (P = .05) and significant reductions in higher-order and primary coma aberrations in the post-LASIK group (P = .04). CONCLUSIONS: Wavefront-guided laser enhancements using the evaluated platform seem to be safe and effective to restore the visual function in aberrated eyes.

Comparison of visual outcomes after variable spot scanning ablation versus wavefront-optimized myopic LASIK.

PURPOSE: To compare the refractive and visual outcomes of variable spot scanning ablation versus the wavefront-optimized ablation for myopia and myopic astigmatism. METHODS: Fifty patients with myopia who underwent LASIK (100 eyes) were divided into two equal groups. Myopic correction performed using the variable spot scanning (VSS) ablation with the VISX STAR S4/IR platform (Abbott Medical Optics, Inc., Santa Ana, CA) (VSS group) and wavefront-optimized (WFO) ablation profile with the WaveLight Allegretto Wave Eye-Q platform (Alcon Laboratories, Inc., Fort Worth, TX) (WFO group). Manifest refraction, uncorrected distance visual acuity, and corrected distance visual acuity were obtained preoperatively and 1 day and 1 and 3 months postoperatively. Wavefront measurement and contrast sensitivity testing were done preoperatively and 3 months postoperatively. RESULTS: Postoperative mean refractive spherical equivalent was -0.14 ± 0.2 diopters for the VSS group and -0.15 ± 0.28 diopters for the WFO group. Forty-eight eyes of the VSS group and 47 eyes of the WFO group were within ±0.5 diopters. Postoperative mean corrected distance visual acuity was 1.05 ± 0.13 for the VSS group and 1.06 ± 0.12 for the WFO group. The postoperative uncorrected distance visual acuity was 1.01 ± 0.16 for the VSS group and 1.01 ± 0.11 for the WFO group. The safety index was 1.12 for the VSS group and 1.06 for the WFO group, whereas the efficacy index was 1.07 for the VSS group and 1.01 for the WFO group. The mean induced positive spherical aberration was 0.041 ± 0.046 µm for the VSS group and 0.195 ± 0.171 µm for the WFO group (P < .001). Mesopic contrast sensitivity testing showed no statistically significant differences between groups at all tested spatial frequencies. CONCLUSIONS: Both VSS and WFO treatments showed similar refractive and visual outcomes. Both induced significant positive spherical aberration, significantly more with WFO.

Visual outcome after correcting the refractive error of large pupil patients with wavefront-guided ablation.

PURPOSE: To investigate the efficacy and predictability of wavefront-guided laser in situ keratomileusis (LASIK) treatments using the iris registration (IR) technology for the correction of refractive errors in patients with large pupils. SETTING: Horus Vision Correction Center, Alexandria, Egypt. METHODS: Prospective noncomparative study including a total of 52 eyes of 30 consecutive laser refractive correction candidates with large mesopic pupil diameters and myopia or myopic astigmatism. Wavefront-guided LASIK was performed in all cases using the VISX STAR S4 IR excimer laser platform. Visual, refractive, aberrometric and mesopic contrast sensitivity (CS) outcomes were evaluated during a 6-month follow-up. RESULTS: Mean mesopic pupil diameter ranged from 8.0 mm to 9.4 mm. A significant improvement in uncorrected distance visual acuity (UCDVA) (P < 0.01) was found postoperatively, which was consistent with a significant refractive correction (P < 0.01). No significant change was detected in corrected distance visual acuity (CDVA) (P = 0.11). Efficacy index (the ratio of postoperative UCDVA to preoperative CDVA) and safety index (the ratio of postoperative CDVA to preoperative CDVA) were calculated. Mean efficacy and safety indices were 1.06 ± 0.33 and 1.05 ± 0.18, respectively, and 92.31% of eyes had a postoperative spherical equivalent within ±0.50 diopters (D). Manifest refractive spherical equivalent improved significantly (P < 0.05) from a preoperative level of -3.1 ± 1.6 D (range -6.6 to 0 D) to -0.1 ± 0.2 D (range -1.3 to 0.1 D) at 6 months postoperative. No significant changes were found in mesopic CS (P ≥ 0.08), except CS for three cycles/degree, which improved significantly (P = 0.02). Magnitudes of primary coma and trefoil did not change significantly (P ≥ 0.34), with a small but statistically significant increase in primary spherical aberration. CONCLUSION: Wavefront-guided LASIK provides an effective correction of low to moderate myopia or myopic astigmatism in large pupil patients without deterioration of visual quality.

Improving near vision in presbyopic eyes by selective treatment of high-order aberrations.

PURPOSE: Evaluation of improving near vision in presbyopic patients with low to moderate myopia with selective treatment of high-order aberrations (HOAs) using the ORK-CAM software aberrometer and a SCHWIND ESIRIS excimer laser. In this study, all HOAs except vertical coma were treated and the effect on near visual function was evaluated. SETTING: Horus Vision Correction Center, Alexandria, Egypt. METHODS: Twenty-six presbyopic patients (52 eyes) with low to moderate myopia were divided into two groups, A and B. The ORK-CAM software aberrometer was used in both groups to measure HOAs and design wavefront-guided treatment. All included eyes had total coma >0.2 µm. The Moria M2 mechanical microkeratome was used for flap making in both groups. Wavefront-guided laser-assisted in situ keratomileusis using ESIRIS laser was done for all eyes. In Group A (30 eyes) all HOAs were treated. In Group B (22 eyes) vertical coma was left untreated. Postoperative uncorrected distance visual acuity (UCVA), best corrected distance visual acuity (BCVA), uncorrected near acuity (UCNA), distance corrected near acuity (DCNA), best corrected near acuity with addition for near vision (BCNA), manifest refractive spherical equivalent (MRSE), HOAs, and contrast sensitivity for both groups were done preoperatively and at 3 months postoperatively. RESULTS: Mean age was 47.46 and 45.2 years for groups A and B, respectively. Mean preoperative MRSE was -2.37 and -2.87 D and mean preoperative total HOAs was 0.35 and 0.38 µm in groups A and B, respectively. There was no significant difference between groups regarding age, sex, preoperative MRSE, and preoperative total HOAs. After 3 months, there was no significant difference between groups in terms of UCVA, BCVA, MRSE, and contrast sensitivity. Analysis of postoperative HOAs showed significant difference in vertical coma between the two groups (P < 0.001). DCNA was significantly better in Group B (P < 0.01). CONCLUSION: Treating low to moderate myopia with wavefront-guided ablation including selective treatment of HOAs might be very useful for improving visual functions. Treating all HOAs but the vertical coma improved uncorrected near acuity in presbyopic patients.