Intraocular pressure fluctuation following intravitreal dexamethasone implant and incidence of secondary ocular hypertension: a Zambian perspective

Abstract

Introduction: to evaluate the effect of dexamethasone biodegradable implant (DEX-I), on intraocular pressure (IOP), to determine the incidence of secondary ocular hypertension (OHT) and to analyze the IOP changes as per the treatment indication in Zambian cohort.

Methods: retrospective consecutive case series of patients receiving one DEX-I between January 2016 and September 2018 with a minimum follow-up of four months in a tertiary care centre in Zambia. The IOP was recorded before the injection and at 1^st week, 1^st, 2^nd, 3^rd and 4^th month after the injection. Ocular hypertension was defined as IOP ≥ 21 mmHg or an increase of ≥ 10 mmHg from baseline.

Results: the effects of 122 injections given to ninety - nine patients (65 male:65%; mean age 57.3) were included. The main indications for treatment were diabetic macular edema (DME, 52%), retinal vein occlusion (18%), post-surgical macular edema (18%) and non-infectious posterior uveitis (10%). Mean IOP before the injection was was 14.7mmHg and at 1^st week, 1^st, 2^nd, 3^rd and 4^th months after the injection it was 14.4 (p=0.08), 16.1 (p=0.01), 17.5 (p<0.001), 15.7 (p=0.006) and 14.9 (p=0.06) mmHg, respectively. The incidence of secondary OHT was 30.32% in this cohort. Peak incidence of OHT was between 1 - 2 months, with majority of cases in DME group (75%) and 43% diabetic eyes followed by 23% non-infectious posterior uveitis cases developing OHT post injection. OHT was well managed with anti-glaucoma medications only.

Conclusion: DEX-I showed a good pressure tolerance in this cohort. Secondary ocular hypertension developed in one-third of patients receiving injection which was transient and successfully managed with topical anti-glaucoma medications only. Diabetic eyes are more prone to develop ocular hypertension and therefore needs close monitoring following injection.