Randomized trial comparing multilayer amniotic membrane transplantation with scleral and corneal grafts for the treatment of scleral thinning after pterygium surgery associated with beta therapy.

Abstract

The aim of this study was to compare the use of multilayer amniotic membrane transplantation (AMT) with lamellar corneal transplantation (LCT) and lamellar scleral transplantation (LST) for the treatment of scleral thinning after pterygium surgery associated with beta therapy. Twenty-six eyes from 26 different patients with scleral thinning as a consequence of beta therapy after pterygium surgery were evaluated at the Federal University of São Paulo, Brazil. Ophthalmologic examination and ultrasound biomicroscopy were performed to assess scleral thinning before the transplant surgery and then repeated at 30, 90, and 180 days after surgery. An increase in scleral thickness, epithelialization of the ocular surface, and preservation of the ocular globe were the main outcome measures. Irrespective of the surgical technique used (AMT, LCT, or LST), no clinical or statistical changes in corrected distance visual acuity were found in any of the patients during this study. The median preoperative scleral thickness was similar in all 3 groups: AMT = 0.45 mm, LST = 0.48 mm, and LCT = 0.52 mm (P = 0.257); however, 6 months after surgery, the median thickness in the AMT group (0.19) was significantly less than that of the LCT group (0.57) (P = 0.27) or the LST group (0.76) (P = 0.19). Epithelialization occurred in all the patients. LCT was the best option for the structural treatment of scleral thinning, followed by LST with a conjunctival flap. A high rate of reabsorption was found with AMT, which was the least effective of the 3 therapeutic options and should not be used for this condition.