Abstract
Purpose: :
To determine if mean central macular thickness (CMT) as measured by optical coherence tomography (OCT) correlates with visual acuity in patients receiving a posterior subtenon’s injection of triamcinolone for cystoid macular edema (CME) of varying etiologies.
Methods: :
We performed a retrospective chart review of patients seen at the Geneva Eye Clinic, Geneva, IL from 4/2004 to 11/2005. Patients had a diagnosis of CME confirmed by fluoroscein angiography and OCT (OCT 3). 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 pre and post–injection. Snellen visual acuities were obtained pre and post–injection and then converted to logMAR for purposes of statistical analysis.
Results: :
Twenty eyes of sixteen patients were included. The patients were divided into 4 diagnostic groups based upon CME etiology: diabetic retinopathy (DR) (6 pts, 9 eyes), central retinal vein occlusion (CRVO) (2 pts, 2 eyes), Irvine–Gass syndrome (IG) (4 pts, 4 eyes) and posterior uveitis (4 pts, 5 eyes). Each eye received between 1 and 5 injections (mean 2.6). Follow–up time after treatment was between 1 and 11 months (mean 3.1). The mean pre–injection and post–injection CMT per diagnostic group was as follows: DR 423.2 µm (range 317 – 509 µm) and 402.5 µm (range 267 – 521 µm); CRVO 581.3 µm (range 474 – 634 µm) and 575.3 µm (range 345–730 µm); IG 457.0 µm (range 326 – 554 µm) and 351.0 µm (range 195 – 496 µm); posterior uveitis 534.9 µm (range 273– 928 µm) and 441.7 µm (range 178 – 735 µm). Pearson Product Moment correlation coefficients (r) were calculated for change in vision and change in macular thickness by diagnostic group. The correlation coefficients in each group were as follows: DR 0.43 (R2 = 0.18); CRVO 0.94 (R2 = 0.88); IG 0.89 (R2 = 0.79); posterior uveitis 0.56 (R2 = 0.31).
Conclusions: :
Our results demonstrate a strong relationship between visual acuity and CMT in patients with CME secondary to CRVO and Irvine–Gass syndrome, a good relationship in uveitic CME, and a fair to moderate relationship in diabetic CME. Weaknesses of our study include small sample size, limited follow–up period and unregulated time of follow–up. Additional studies are needed to determine if the correlation seen in this small group can be reproduced in a larger population.
Keywords: macula/fovea • imaging/image analysis: clinical • clinical (human) or epidemiologic studies: outcomes/complications