Objective: To investigate whether peripheral corneal neovascularization in bullous keratopathy (BK) is due to conjunctivalization, a sign of limbal stem cell deficiency.
Design: Observational case-control study.
Participants: Sixteen BK patients.
Methods: Patients were divided into 2 groups: BK without peripheral neovascularization [NV(-) group; 5 patients, 5 eyes] and BK with neovascularization [NV(+) group; 11 patients, 13 eyes]. Evidence of conjunctivalization was evaluated by periodic acid-Schiff staining of impression cytology samples from the peripheral vascularized cornea. The 2 groups' durations of disease also were compared. Penetrating keratoplasty (PK) was performed in all 16 cases, and the 2 groups' durations of reepithelialization after PK were compared.
Main outcome measures: Presence of goblet cells using impression cytology, duration of BK, and duration of postoperative reepithelialization.
Results: Goblet cells were found on the peripheral corneal surface in all eyes in the NV(+) group. However, all eyes in the NV(-) group were negative for goblet cells (P<0.0001). Duration of disease was 14.4+/-5.4 months in the NV(-) group and 66.2+/-65.5 months in the NV(+) group (P = 0.030). Duration of postoperative epithelialization was 6.2+/-2.2 days in the NV(-) group and 28.8+/-36.5 days in the NV(+) group (P = 0.046).
Conclusion: Conjunctivalization of the peripheral cornea and delayed postoperative epithelialization in BK patients with NV suggest the presence of limbal stem cell deficiency in such patients. Patients with long-standing disease were found to be more prone to neovascularization. For this reason, early surgery may lead to a better surgical outcome.