Fluorescein angiography versus superimposed OCT-guided macular laser photocoagulation

Abstract

Purpose: To compare diabetic macular edema (DME) laser treatment plans using fluorescein angiography (FA) versus optical coherence tomography (OCT) template superimposed on the retinal image. We hypothesize that information from integrated OCT retinal thickness map aligned onto fundus image will have an impact on treatment plan for these patients.

Methods: Eight eyes of five patients with DME undergoing laser photocoagulation with navigated photocoagulator NAVILAS® (OD-OS, Inc., Berlin, Germany) had FA and OCT imaging done before treatment. FA image was taken with the same instrument and superimposed onto color fundus photo. OCT retinal thickness map taken on the Heidelberg Spectralis system (Heidelberg Engineering, Vista, CA) was imported to the laser photocoagulator unit and superimposed and aligned onto fundus image of the same magnification off line. The treatment plans for each eye consisted of placing laser spot marks separately on FA and OCT image in a masked fashion. The number of spots placed by physician was compared between FA and OCT using matched pairs analysis. The area of dye leakage on FA and increased retinal thickness on OCT on the same eye was measured using Heidelberg Explorer software.

Results: Three masked retina specialists created treatment plans. The average number of planed spots using FA and OCT template was 36.67 and 42.20, respectively (p=0.0015). The average area of dye leakage on FA was 7.45 mm2 whereas the average area of increased retinal thickness on OCT superimposed on fundus image of the same eye was 10.92 mm2 (p=0.013).

Conclusions: In eyes with DME the area of retinal thickening appears to be larger on OCT image than the area of dye leakage on FA templates. Physicians had a tendency to place more laser spots when guided by OCT than FA. Integration of OCT map aligned to retina may have an impact on treatment plan once this alignment takes place and such information is available.