An Analysis of Factors Influencing Quality of Vision After Big-Bubble Deep Anterior Lamellar Keratoplasty in Keratoconus

PURPOSE: To identify causes of reduced visual acuity and contrast sensitivity after big-bubble deep anterior lamellar keratoplasty (DALK) in keratoconus. DESIGN: Prospective interventional case series. METHODS: This study included 36 eyes in 36 patients with keratoconus who underwent DALK using the big bubble technique. A bare Descemet membrane was achieved in all cases. Univariate analyses and multiple linear regression were used to investigate recipient-, donor-, and postoperative-related variables capable of influencing the postoperative quality of vision, including best spectacle-corrected visual acuity (BSCVA) and contrast sensitivity. RESULTS: The mean patient age was 27.7 +/- 6.9 years, and the patients were followed for 24.6 +/- 15.1 months postoperatively. The mean postoperative BSCVA was 0.17 +/- 0.09 logMAR. Postoperative BSCVA >= 20/25 was achieved in 14 eyes (38.9%), whereas a BSCVA of 20/30, 20/40, or 20/50 was observed in 15 eyes (41.7%), 6 eyes (16.6%), and 1 eye (2.8%), respectively. Preoperative vitreous length was significantly associated with postoperative BSCVA (beta = 0.02, P = .03). Donor-recipient interface reflectivity significantly influenced scotopic (beta = -0.002, P = .04) and photopic (beta = -0.003, P = .02) contrast sensitivity. The root mean square of tetrafoil was significantly negatively associated with scotopic (beta = -0.25, P = .01) and photopic (beta = -0.23, P = .04) contrast sensitivity. Recipient age, keratoconus severity, donor related variables, recipient trephination size, and graft and recipient bed thickness were not significantly associated with postoperative visual acuity or contrast sensitivity. CONCLUSION: Large vitreous length, higher-order aberrations, and surgical interface haze may contribute to poor visual outcomes after big-bubble DALK in keratoconus. (C) 2016 by Elsevier Inc. All rights reserved.