Prevalence, progression, and impact of glaucoma on vision after Boston type 1 keratoprosthesis surgery.

PURPOSE

To report glaucoma outcomes after Boston type 1 keratoprosthesis (KPro) surgery, in particular, glaucoma prevalence, progression, and treatment.

DESIGN

Consecutive, retrospective, interventional case series.

METHODS

setting: Tertiary care institution. study population: Thirty-eight eyes in 38 patients. intervention: KPro surgery. main outcome measures: Visual acuity (VA), intraocular pressure, visual fields, optic nerve status, and glaucoma treatment.

RESULTS

Glaucoma diagnosis was known before surgery in 29 patients (76%; 14 had undergone previous surgery) and was diagnosed after surgery in 34 patients (89%) after a mean ± standard deviation of 16.5 ± 4.7 months of follow-up. The number of patients taking intraocular pressure-lowering medications increased from 19 (50%) before surgery to 28 (76%) after surgery (P = .017). Twenty-four patients (63%) were taking at least 1 additional glaucoma medication at their most recent postoperative visit. Eight patients (21%) had glaucoma progression (visual field progression, need for surgery, or both). Fifteen patients (40%) had a cup-to-disc ratio of 0.85 or more. Five patients required glaucoma surgery. VA was limited by glaucoma in 14 patients (37%), 11 of whom had a VA of 20/200 or worse. Five such patients (13%) had a dramatic improvement in VA, then progressed to end-stage glaucoma with fixation loss. Visual fields were limited by glaucoma in 25 patients (66%; mean Swedish Interactive Threshold Algorithm Fast mean defect, -20.3 ± 8.8 decibels; n = 18).

CONCLUSIONS

Most KPro candidates have glaucoma, which may deteriorate in a subset of patients after surgery. Dramatic VA improvement after KPro surgery does not preclude the need for rigorous monitoring for glaucoma progression. A low threshold should be used to treat suspicion of even slightly elevated intraocular pressure.