Superiority of indocyanine green angiography to fluorescein angiography for detection of leaking spots in diffuse diabetic macular edema

Abstract

 

Purpose

 

We have previously reported the usefulness of indocyanine green angiography (ICGA) for assessment and focal laser photocoagulation (PHC) of diffuse diabetic macular edema (DME) as well as idiopathic macular telangiectasia type 1 (ARVO2014 #1789, BJO 2010;94:600). The purpose of this study is to quantify the detectability of leaking spots in diffuse DME by ICGA and evaluate long-term efficacy of ICGA-guided PHC.

 

Methods

 

Nine eyes of 9 patients with diffuse DME diagnosed on the basis of fluorescein angiography (FA) were enrolled. FA and ICGA were performed using the Heidelberg Retina Angiogram 2. A retinal thickness map of 6 x 6 mm was achieved by cirrus optical coherence tomography (OCT). Hyperfluorescent spots was marked on FA in the early phase and on ICGA in the early and late phases and superimposed onto the OCT map to calculate the number of hyperfluorescent spots and the area of the inside and outside of lesions with macular edema (ME) thicker than 400 µm by using Image J software. ICGA-guided PHC was performed on the basis of late phase ICGA. The best-collected visual acuity (BCVA) and the central retinal thickness (CRT) were measured at baseline and in month 24.

 

Results

 

Table 1 shows the density (spots per disc area [spots/DA]) in the early phase of FA and in the early and late phases of ICGA. In the early phase of FA, many hyperfluorescent spots were observed both in the areas with ME and outside ME. In contrast, the number of hyperfluorescent spots in the late phase of ICGA significantly decreased as compared with the early phase of FA (p<0.01, t-test).<br /> Hyperfluorescent spots were predominantly observed in the area with ME especially in the late phase of ICGA. ME as large as 1DA involved 1.8 leaking spots in average. Mean BCVA in the LogMAR unit was significantly improved from 0.63 at baseline to 0.41 (p<0.05), the mean CRT was significantly decreased from 408 μm to 274 μm (p<0.05).

 

Conclusions

 

ICGA can detect only responsible leaking spots for diffuse DME especially in the late phase, potentially making focal laser photocoagulation more feasible and less invasive.