Peripheral ischemic index assessment by wide field digital fluorescein angiography: Potential liaison with macular edema and macular choroidal thickness in diabetic retinopathy

Session Details

Session Title: Free Paper Session 12: Imaging I

Session Date/Time: Friday 08/09/2017 | 14:30-16:00

Paper Time: 14:36

Venue: Room 111

First Author: : S.Chandra INDIA

Co Author(s): :    J. Sheth   A. Giridhar                          

Abstract Details


Researchers have correlated peripheral retinal ischaemia with severity of diabetic retinopathy, but its relationship with macular edema and choroidal thickness (CT) remains unexplored. Current study aimed to elucidate these lacunae by assessing the connexion between peripheral retinal ischaemia in DR, assessed on widefield fluorescein angiography, with macular edema and choroidal thickness.


Treatment-naive patients with diabetes presenting to Vitreo-Retina Clinic, Giridhar Eye Institute, Kerala, India, between July 2015 and September 2015 were included. This study was conducted in accordance to the tenets of Declaration of Helsinki and was approved by the Institutional Review Board. Written informed consent was obtained from each patient.


Prospective study of diabetic patients undergoing enhanced-depth imaging (EDI)-OCT for measurement of subfovealchoroidal thickness (SFCT), at 1500 & 3000µm nasally and temporally (N1500, N3000, T1500, T3000). Additionally, digital widefield fluorescein angiography (102°;WF-DFA)was performed on Spectralis (Heidelberg, Germany). Areas of peripheral ischaemia, defined as area of capillary non-perfusion on WF images, were delineated manually & area calculated in pixels by a single grader. A Peripheral Ischaemic Index (PII), defined as ratio of total CNP areas and total area of WF image, was calculated. Correlation coefficients for various parameters with PII was calculated using Spearmans correlation.


Analysis included 161 eyes of 86 patients with DR. Eighty-five eyes had NPDR and 76 eyes had PDR. The mean age was 57.9 ±8.7 years, and gender ratio of 2:3 (Male:Female). Overall, Central Macular Thickness (CMT) was negatively correlated with PII in all eyes with DR. In subgroup analysis, it was negatively correlated in PDR subgroup while it was positively correlated in NPDR eyes. However, none of these associations was statistically significant. Choroidal thickness at each loci had a negative correlation with PII in all eyes with DR (SFCT: p<0.004) and in NPDR eyes (SFCT:p<0.005). This correlation between choroidal thickness at all points with PII was statistically significant. However, in PDR group, although this relationship was negatively correlated, it was not statistically significant.


Macular choroidal thickness can be considered as a putative measure of choroidal blood flow and consequently a marker of tissue oxygenation. Current study establishes an inverse relationship between amount of peripheral retinal ischaemia and macular choroidal thickness in DR thereby suggestive of concomitant diabetic choroidopathy with progressive peripheral retinal ischaemia.

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