Acanthamoeba Keratitis Secondary Glaucoma Associated With Mature Cataract and a Fixed Dilated Pupil in a 40-Eye Series.

Purpose: This case series describes the incidence, clinical associations, and treatment outcomes of Acanthamoeba keratitis (AK) secondary glaucoma to identify potential prophylactic measures and optimal treatment.

Methods: AK-affected eyes developing secondary glaucoma from 1992 to 2020 were identified from Moorfields databases. The annualized incidence was established from those patients with AK registered between 2000 and 2015.

Results: The 2000-2015 incidence of AK secondary glaucoma was 26 of 417 (6.2%). Forty eyes (39 patients) developed glaucoma or ocular hypertension; 16 of 28 (57%) had been treated for AK for ≥12 months from onset. Thirty-four of 40 eyes (85%) had an associated keratoplasty; 26 of 40 (65%) had a fixed dilated pupil and/or mature cataract. Sixteen of 40 (40%) underwent antiglaucoma drug treatment alone. Twenty-four of 40 (60%) eyes had surgical treatments including cyclodiode laser (2 eyes) leading to phthisis or evisceration, trabeculectomy (2 eyes) failed, glaucoma drainage devices in 20 of 40 (50%) eyes resulted in glaucoma control in 18/20 (90%) but required additional surgery in 9 of 20 (45%) eyes.

Conclusions: Mature cataract or a fixed dilated pupil has not been previously identified as a cause of secondary glaucoma in AK. The implications are that both result in angle closure and that early surgery for maturing cataract, despite its complexity, might prevent the development of angle closure. However, the potential for better medical treatment to reduce the time to cure to less than 12 months is likely the most effective way to reduce AK glaucoma incidence. Successful management of AK glaucoma once developed probably requires use of a glaucoma drainage device.