Pro Re Nata Dexamethasone Implant for Treatment-Naive Phakic Eyes with Diabetic Macular Edema: A Prospective Study

Abstract

Purpose: To determine the utility and safety of the intravitreal dexamethasone implant as primary therapy (pro re nata [PRN]) in phakic eyes with early treatment-naive diabetic macular edema (DME).

Design: Prospective, case series.

Participants: Patients with diabetes mellitus whose eyes were phakic and had early treatment-naive clinically significant macular edema.

Methods: Patients whose eyes were phakic with DME (<3 months) were included if the central subfield thickness (CST) was >300 μm and corrected distance visual acuity (CDVA) between 0.3 and 1.0 logarithm of minimum angle of resolution. A comprehensive ocular and systemic examination was performed and the implant injected PRN using a standardized technique. Patients had follow-up at least monthly for 2 years. Descriptive statistics were used to analyze categorical variables in terms of size and proportions. The repeated-measures analysis of variance test was used to determine the change in CDVA, CST, intraocular pressure, and hard exudate area over time.

Main outcome measures: The primary outcome measure was the determination of the change in CDVA at month 24 from baseline. Secondary outcome measures included determining the change in CST, median number of injections, proportion gaining 15 letters, and complications, if any.

Results: A total of 153 patients (85 males) were included. At 2 years, mean CDVA improved from 0.62 to 0.4 logarithm of minimum angle of resolution, and median CST improved from 397 to 236 μm. The median number of injections was 1.6. Cataract developed in 3 patients with a clear lens, and 31 patients required topical antiglaucoma therapy. Proliferative disease developed in 4 patients, which was managed with panretinal photocoagulation. None of the study patients required rescue therapy.

Conclusions: In patients with treatment-naive phakic eyes who had DME, primary therapy with the intravitreal dexamethasone implant PRN (for 2 years) resulted in significantly improved mean CDVA. A fifth of the patients required control of intraocular pressure, and new-onset cataract developed in 3 of 153 patients.