Corneal Changes After Collagen Crosslinking for Keratoconus Using Dual Scheimpflug Imaging.

PURPOSE: To evaluate corneal changes after collagen crosslinking (CXL) therapy for keratoconus (KCN) using the Galilei dual Scheimpflug analyzer. METHODS: This prospective, nonrandomized clinical study included 35 eyes of 32 keratoconus patients who had undergone CXL. The eyes were saturated with riboflavin solution and were subjected for 30 minutes to ultraviolet-A (UV-A) light with irradiance of 3 mW/cm(2). Effectiveness of the treatment was assessed by measuring uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest cylinder/sphere, keratometry, pachymetry, posterior and anterior elevations by the Galilei dual Scheimpflug analyzer. Prior to treatment and 8 months after therapy, Scheimpflug analysis was performed using the Galilei system. The four sets of data including keratometry values, pachymetry, elevation parameters and surface indices were statistically analyzed and compared. RESULTS: Mean patient age was 22.3 ± 3.8 years and mean postoperative follow-up was 8.1 ± 3.2 months. There was a significant increase in UCVA (0.54 ± 0.35 Log MAR preoperatively to 0.49 ± 0.34 LogMAR postoperatively, P = 0.01) and BCVA (0.21 ± 0.19 Log MAR preoperatively to 0.16 ± 0.17 LogMAR postoperatively, P = 0.01). Mean cycloplegic spherical equivalent refractive error was -4.13 ± 2.65 Diopter (D) preoperatively and - 4.67 ± 2.96 D postoperatively (P < 0.001). During the follow-up period, no significant difference was observed in pachymetric and elevation data postoperatively. CONCLUSION: Corneal stabilization could be achieved by collagen crosslinking therapy for keratoconus in terms of corneal thickness, keratometry values, elevation parameters and surface indices.

Superior versus inferior Ahmed glaucoma valve implantation.

PURPOSE: To compare the efficacy and safety of Ahmed glaucoma valve (AGV) (New World Medical Inc., Rancho Cucamonga, CA) implantation in the superior versus inferior quadrants. DESIGN: Prospective parallel cohort study. PARTICIPANTS: A total of 106 eyes of 106 patients with refractory glaucoma. METHODS: Consecutive patients with refractory glaucoma underwent AGV implantation in the superior or inferior quadrants. MAIN OUTCOME MEASURES: Main outcome measures included intraocular pressure (IOP) and rate of complications. Other outcome measures included best corrected visual acuity (BCVA), number of glaucoma medications, and success rate (defined as at least 30% IOP reduction and 50.122). After 1 year, statistically significant but comparable IOP reduction from baseline (P<0.001) was achieved in both groups (47.0%+/-27.2% and 43.0%+/-24.5% reduction for superior and inferior groups, respectively, P = 0.725). The mean number of glaucoma medications was comparable after 1 year (1.3+/-1.2 vs. 1.9+/-0.8 for superior and inferior implants, respectively, P = 0.256). Success rates were also similar at 1 year: 27 eyes (81.8%) versus 20 eyes (95.2%) for superior and inferior implants, respectively (P = 0.227). However, the overall rate of complications, such as implant exposure necessitating removal, cosmetically unappealing appearance, and endophthalmitis, was higher in the inferior group: 12 eyes (25%) versus 3 eyes (5.2%) for superior and inferior groups, respectively, (P = 0.004). CONCLUSIONS: Superior and inferior AGV implants have similar intermediate efficacy in terms of IOP reduction, decrease in number of glaucoma medications, and preservation of vision. However, the inferior quadrants entail significantly more complications. It may be prudent to avoid AGV implantation in the inferior quadrants if the superior quadrants have no contraindications to surgery. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Astigmatic Outcomes of Temporal versus Nasal Clear Corneal Phacoemulsification.

PURPOSE: To compare the astigmatic outcomes of phacoemulsification cataract surgery using temporal versus nasal clear corneal incisions. METHODS: In a clinical trial, consecutive patients with senile cataracts underwent phacoemulsification and implantation of a hydrophobic acrylic foldable intraocular lens through a horizontal clear corneal incision (temporal in right and nasal in left eyes). Outcome measures included keratometric astigmatism and surgically induced astigmatism (SIA) calculated by the vector analysis method using the Holladay-Cravy- Koch formula. RESULTS: The nasal and temporal groups consisted of 20 eyes each. Mean preoperative keratometric astigmatism was 0.63±0.48 D and 0.38±0.39 D in the temporal and nasal incision groups respectively (P=0.09). Data on 10 eyes in each study group was available for the six-month analysis. Mean keratometric astigmatism was as follows in the temporal and nasal groups respectively: 0.85±0.47 D versus 1.95±0.45 D at 1 week (P<0.001), 0.73±0.46 D versus 1.79±0.55 D at 4 weeks (P<0.001), and 0.63±0.30 D versus 1.05±0.56 D at 6 months (P=0.053) after surgery. SIA at the same follow-up intervals was 0.71±0.20 D versus 1.80±0.22 D (P<0.001), 0.63±0.20 D versus 1.65±0.31 D (P<0.001) and 0.26±0.46 D versus 0.92±0.36 D (P=0.002) in the temporal versus nasal incision groups respectively. CONCLUSION: Temporal clear corneal phacoemulsification induces significantly less astigmatism as compared to similar surgery using the nasal approach.