Acanthamoeba keratitis in patients wearing scleral contact lenses.

PURPOSE: To report a series of cases of Acanthamoeba keratitis (AK) in scleral lens wearers with keratoconus to determine whether this type of contact lens presents a greater risk for development of infection. METHODS: This study reports three patients who wore scleral contact lenses to correct keratoconus and developed AK. The diagnoses of AK were established based on cultures of the cornea, scleral contact lenses, and contact lens paraphernalia. This study investigated the risk factors for infections. RESULTS: The possible risks for AK in scleral contact lens wearers are hypoxic changes in the corneal epithelium because of the large diameter and minimal tear exchange, use of large amounts of saline solution necessary for scleral lens fitting, storing the scleral lens overnight in saline solution rather than contact lens multipurpose solutions, not rubbing the contact lens during cleaning, and the space between the cornea and the back surface of the scleral lens that might serve as a fluid reservoir and environment for Acanthamoeba multiplication. Two patients responded well to medical treatment of AK; one is still being treated. CONCLUSIONS: The recommendations for use and care of scleral contact lenses should be emphasized, especially regarding use of sterile saline (preferably single use), attention to rubbing the lens during cleaning, cleaning of the plunger, and overnight storage in fresh contact lens multipurpose solutions without topping off the lens solution in the case.

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.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.