Abstract
Purpose: :
To evaluate retinal blood flow using the Retinal Function Imager (RFI) (Optical Imaging Ltd., Israel) in patients with epiretinal membrane (ERM).
Methods: :
A retrospective case series composed of patients with ERM who underwent RFI imaging was analyzed. Blood flow data was obtained and the average velocity in the secondary and tertiary arterioles and venules around the parafoveal area was computed.
Results: :
Six patients diagnosed with ERM and had undergone RFI imaging were identified (5 male, 1 female, mean age=66). Each ERM was associated with one of the following: diabetic macular edema, retinal detachment, retinal tear, central retinal vein occlusion, toxoplasmosis chorioretinal scar, and vitreomacular traction. Three patients had an associated systemic condition of diabetes mellitus and/or hypertension. The median preoperative Snellen visual acuity (VA) was 20/200 (range: count fingers (CF) to 20/80). Compared to the normal fellow eye, there was a significant reduction in arterial blood flow velocity in the affected eye for all 6 patients (Mean arterial flow 2.74 + 0.35 mm/s affected eye vs. 3.32 + 0.28 mm/s fellow eye, p=0.01). The mean venous velocity was similarly reduced in the affected eye versus the fellow eye, although the difference was not statistically significant (1.92 + 0.51 vs. 2.26 + 0.41 mm/s, p=0.24). All patients underwent pars plana vitrectomy with membrane peeling. The median postoperative VA improved to 20/80 (range: CF to 20/20). The two patients who had the greatest improvement in VA following surgery also had the greatest initial absolute difference in blood flow between the affected and fellow eye of about 0.80 mm/s. Three of the 6 patients had postoperative RFI imaging performed between 1 week to 1 month after surgery, and in each of these patients there was a significant improvement in arterial flow postoperatively (Mean preop 2.90 + 0.30 vs. 3.46 + 0.14 mm/s postop, p=0.03). There was a similar, though not significant, improvement in venous blood flow (Mean preop 2.15 + 0.60 vs. 2.57 + 0.23 mm/s postop, p=0.33). The patient with the greatest improvement in vision also had the greatest increase in postoperative retinal blood flow.
Keywords: imaging/image analysis: clinical • blood supply • retina