Effect of Posterior Subtenon’s Injection of Kenalog on Central Macular Thickness Measured by Optical Coherence Tomography and Visual Acuity

Abstract

Abstract: : Purpose: To determine if a change in mean central macular thickness (µm) correlates with a change in visual acuity in patients who have had a posterior subtenon’s injection of Kenalog for cystoid macular edema (CME). Methods:We performed a retrospective chart review of patients seen at the Geneva Eye Clinic, Geneva, IL from 4/20/2004 to 11/16/2004. Patients enrolled had a diagnosis of CME confirmed by fluoroscein angiography and optical coherence tomography (OCT). All patients received a posterior subtenon’s injection of 0.5 cc Kenalog 40 mg/ml in the study eye. One physician (NB) performed all the injections. OCT was performed on all patients post–injection. Snellen visual acuities were obtained pre and post–injection. Results: Twenty–nine eyes of sixteen patients were included in the study. The diagnosis of CME was secondary to etiologies including diabetic retinopathy, central vein occlusion, Irvine–Gass syndrome and uveitis. Mean age was 61.3 years (range 29 to 88 yrs). Mean follow up time was 41 days (range 27 to 97 days). The mean pre–injection central macular thickness by OCT (OCT3) was 436.97 µm (range 273 to 823 µm), and the mean post–injection OCT measurement was 386.7 µm (range 211 to 928 µm). This overall difference in mean central macular thickness was statistically significant (p=0.03) (CI 95%). There was no statistically significant difference in VA pre and post–injection (p=0.16) (CI 95%). There was no correlation between change in mean central macular thickness and change in VA (r=0.006). Conclusions: The mean central macular thickness decreased after posterior subtenon's injection for CME. However, there was no statistically significant difference in pre and post–injection VA. Additionally, there was no correlation between the change in mean central macular thickness and change in VA. This may be attributed to our limited follow–up period and limited study enrollment. We are continuing the study to determine if the changes observed will be sustained with additional follow–up.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • clinical (human) or epidemiologic studies: outcomes/complications • retina