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.Partially supported by a grant from Abbott Medical Optics

Expression levels of aldose reductase enzyme, vascular endothelial growth factor, and intercellular adhesion molecule-1 in the anterior lens capsule of diabetic cataract patients

Purpose: To compare the levels of aldose reductase (ALR) enzyme, intercellular adhesion molecule-1 (ICAM-1), and vascular endothelial growth factor (VEGF) in the anterior lens capsule of diabetic versus nondiabetic patients. Setting: Alexandria Main University Hospital, Alexandria, Egypt. Design: Prospective case-control study. Methods: The study enrolled patients undergoing cataract extraction and divided them into 3 groups: eyes that had proliferative diabetic retinopathy (PDR), eyes that had nonproliferative diabetic retinopathy (NPDR), and nondiabetic eyes. The anterior lens capsules were obtained by performing femtosecond laser–assisted capsulorhexis. Concentrations of ALR, ICAM-1, and VEGF in the lens capsule specimens were measured using human enzyme–linked immunosorbent assay. Results: This study comprised 200 patients (200 eyes); 51 eyes had PDR, 49 eyes had NPDR, and 100 eyes were nondiabetic. The mean ALR, ICAM-1, and VEGF levels in the anterior capsule of diabetic group were 2.84 nanogram (ng)/mL ± 0.51 (SD), 87.73 ± 22.84 picogram (pg)/mL, and 75.53 ± 14.95 pg/mL, respectively; whereas, in the nondiabetic group, they were 1.44 ± 0.17 ng/mL, 35.45 ± 2.8 pg/mL, and 33.55 ± 5.47 pg/mL, respectively. In comparing the concentrations of these mediators, both the PDR and NPDR groups had significantly higher levels compared with the nondiabetic eyes (P < .001). In addition, eyes with PDR had significantly higher levels of these mediators than eyes with NPDR (P < .001). Conclusion: The concentrations of ALR, ICAM-1, and VEGF in the anterior lens capsule of diabetic patients are significantly higher than those of nondiabetics. A significantly higher level of 3 mediators in eyes with PDR compared with those with NPDR might allow the use of them as a biomarker for severity of diabetic retinopathy.Dr. Piñero has been supported by the Ministry of Economy, Industry and Competitiveness of Spain within the program Ramón y Cajal, RYC-2016-20471

The 7-Year Outcomes of Epithelium-Off Corneal Cross-linking in Progressive Keratoconus

PURPOSE: To evaluate the clinical results of epitheliumoff corneal cross-linking (CXL) during a 7-year follow-up. METHODS: This retrospective, non-randomized, single-center interventional study enrolled 34 consecutive eyes of 24 patients with progressive keratoconus undergoing CXL surgery with epithelium removal. Visual, refractive, corneal topographic, pachymetric, and anterior segment changes were evaluated at 1, 3, and 7 years after surgery. RESULTS: Significant reduction of refraction was observed at 1 year postoperatively (P ≤ .006), with an additional significant reduction between the 1- and 3-year postoperative visits (P ≤ .002) and no significant changes afterward (P ≥ .156). Regarding corrected distance visual acuity (CDVA), a significant improvement was detected at 1 year after surgery (P < .001), with an additional improvement between 1 and 3 years postoperatively (P = .001), and no significant changes at the end of the follow-up (P = .518). Significant corneal flattening was observed at 1, 3, and 7 years after surgery (P ≤ .041). Likewise, a significant central thinning was observed at 1 year postoperatively (P < .001), with no significant changes afterward (P ≥ .112). Anterior maximum elevation only changed significantly between 1 and 3 years after surgery (P = .002), whereas the posterior maximum elevation changed significantly at all time points of the follow-up (P ≤ .034). No significant changes with surgery in anterior segment volume (P ≥ .377) and anterior chamber depth (P ≥ .142) were detected. CONCLUSIONS: The effect of epithelium-off CXL in progressive keratoconus is maintained 7 years after surgery. Long-term corneal changes after this procedure may be influenced by an age-related corneal stiffening process

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.Dr. Khalifa received an unrestricted educational grant from Abbott Medical Optics Germany GmbH

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.Dr. Khalifa received an unrestricted educational grant from AMO Germany GmbH

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.Supported in part by an unrestricted educational grant from Abbott Medical Optics Inc