Abstract
Purpose::
To report the prevalence of glaucoma and the efficacy of simultaneous or sequential glaucoma drainage device (GDD) implantation in controlling intraocular pressure (IOP) in eyes undergoing Boston type 1 keratoprosthesis (KPro) placement.
Methods::
The medical records of patients who underwent KPro placement with or without concomitant glaucoma surgery between May 2004 and November 2006 were reviewed. Outcome measures include visual acuity, IOP, and postoperative complications.
Results::
31 KPro procedures were performed in 27 eyes of 26 patients. Preoperative diagnoses included multiple graft failures in 18 eyes (69%), Stevens-Johnson syndrome in 4 eyes (13%), repeat KPro in 4 eyes (13%), chemical injury in 3 eyes (10%), and other diagnoses in 2 eyes (6%). Necrosis of the donor cornea necessitated repeat KPro implantation in 4 eyes, two of whom experienced recurrent necrosis and underwent removal of the KPro. 24 eyes (89%) had count fingers vision or worse preoperatively. With average follow up of 11.3 ± 8.1 (range 1-29) months, postoperative vision improved to 20/100 or better in 17 eyes (68%), with 12 (48%) achieving 20/50 vision or better. In the 10 eyes with postoperative vision of 20/200 or worse, the most common cause of limited visual recovery after surgery was preexisting advanced glaucomatous optic neuropathy (5, 50%). 20 eyes (74%) had preexisting glaucoma, of whom the majority (15, 75%) were classified as secondary angle closure glaucoma. Of these 20 eyes with preexisting glaucoma, 9 had previously undergone surgery (8 GDD, 1 trabeculectomy) and did not have an additional glaucoma procedure at the time of the KPro. The remaining 11 eyes had GDDs (Ahmed valves) placed at the same time as the KPro (of these, 5 eyes had prior glaucoma surgery that failed). The 19 eyes with GDDs all (100%) had adequately controlled IOP as measured by finger tension after glaucoma surgery. Two of the 7 (29%) eyes that did not have a history of glaucoma prior to KPro implantation developed angle closure postoperatively and were managed by surgical peripheral iridectomy in one case, and subsequent Ahmed valve placement in the other.
Conclusions::
81% (22/27) of eyes that required KPro implantation had preexisting glaucoma or developed glaucoma afterwards. Glaucoma is the most common cause of limited visual recovery following surgery. All eyes that underwent simultaneous KPro and GDD implantation achieved adequate IOP control after surgery. Due to the high prevalence of glaucoma and the difficulty in IOP estimation, GDD implantation should be considered in all patients that require KPro.
Keywords: keratoprostheses