Abstract
Purpose: :
To determine the indications and outcomes of Boston Type 1 keratoprosthesis surgery performed in Armenia and compare them with those published by surgeons in the United States.
Methods: :
Retrospective review of patients who received Boston Type 1 Keratoprosthesis at Malayan Eye Center, Yerevan, Armenia between May 1, 2006, and November 1, 2010. Preoperative, intraoperative and postoperative data were collected and analyzed.
Results: :
Eighteen keratoprosthesis were implanted in 17 eyes of 12 patients. The most common indication for surgery was chemical injury (n=9), followed by thermal injury (n=2), mucous membrane pemphigoid (n=2), repeat corneal graft failure (n=2), herpetic keratitis with corneal ectasia or perforation (n=2) and repeat keratoprosthesis (n = 1). Preoperative visual acuities were light perception (LP) in 16 eyes and counting fingers at 2 ft in 1 eye. At the final follow-up visit, the corrected distance visual acuity ranged between 20/40-20/200 in 6 eyes (35%), 20/400 in 1 eye, and was LP in 6 eyes (average follow-up 23.0 months; range, 2.4-48.1 months). Five of the 18 keratoprosthesis implanted (29%) in 4 eyes of 3 patients were removed at an average of 5.4 months after implantation (sterile corneal necrosis - 3 eyes; endophthalmitis - 2 eyes) for a retention failure rate of 0.18/eye-year. Elevated intraocular pressure was the most common postoperative complication, developing in 4 eyes (24%), followed by endophthalmitis (3 eyes; 18 %), and retroprosthetic membrane formation, sterile vitritis and sterile corneal stromal necrosis, each in 2 eyes (12%).
Conclusions: :
The indications for keratoprosthesis implantation are significantly different in the United States that they are in Armenia, where chemical injury is the most common indication and repeat corneal graft failure accounts for less than 15% of the procedures performed. Although over a third of patients demonstrated a significant improvement in their vision at the last follow-up visit, a similar percentage remained or returned to LP vision after surgery. The keratoprosthesis retention failure rate and the rate of post-operative endophthalmitis are higher in Armenia than in published series from the United States, likely due to several factors, including differing indications for keratoprosthesis surgery and limited patient compliance with the post-operative treatment protocol. These findings underscore the importance of appropriate patient selection and modification of the post-operative treatment regimen in developing countries.
Keywords: keratoprostheses • clinical (human) or epidemiologic studies: outcomes/complications • clinical (human) or epidemiologic studies: prevalence/incidence