Predominantly Peripheral Diabetic Retinopathy Lesions and Retinopathy Severity are Associated with Peripheral Nonperfusion on Ultrawide Field Fluorescein Angiography

Abstract

 

Purpose

 

To evaluate the association of peripheral nonperfusion (NP) identified on ultrawide field (UWF) fluorescein angiography (FA) with diabetic retinopathy (DR) severity and the presence of predominantly peripheral DR lesions (PPL).

 

Methods

 

UWF images and UWF-FA were acquired at the same visit for 60 eyes of 33 subjects without prior PRP. Stereographically projected UWF images were used to determine DR severity and DR lesion distribution. Standardized ETDRS photo templates were digitally overlaid on UWF images based on disc and macula location with lesions predominantly peripheral to this area deemed PPL. Stereographic projections of the best UWF-FA images near peak fluorescence were evaluated for extent of peripheral NP and global ischemic index (nonperfused/total gradable area; GII). Masked duplicate UWF-FA grading was performed by the same grader and by a separate grader to determine intra- and inter-reader reproducibility in 37 and 23 eyes, respectively.

 

Results

 

The cohort had mean age of 66.1±11.6 years; diabetes duration 22.6±11.9 years; 67% type 2; 67% white; 61% male; mean visual acuity 20/25. DR distribution by UWF images was: no DR 6.7% (4) eyes; nonproliferative DR (NPDR) mild 18.3% (11), moderate 36.7% (22), severe 20% (12); proliferative DR (PDR) 15% (9) and high risk PDR 3.3% (2). There was strong intragrader(r=0.95, 0.95) and intergrader(r=0.74, 0.76) agreement for peripheral NP and GII, respectively. In eyes with no PDR (N =49), peripheral NP increased with worsening DR severity (p=0.049). Predominantly peripheral lesions (PPL) were identified in 38 eyes (63.3%) and were highly associated with increased peripheral NP (GII: 0.26 vs 0.43, p=0.001) and remained significant after correction for baseline DR severity in eyes without PDR (p =0.045). Increasing peripheral NP was associated with worsening DME severity (p=0.046). There was only weak correlation between GII and visual acuity (0.21).

 

Conclusions

 

Standardized evaluation of UWF-FA for peripheral NP and GII is reproducible. Since presence of PPL has been associated with marked increases in future DR progression, and since peripheral NP is highly correlated with PPL in this study, these data suggest that PPL might reflect increases in peripheral NP that may mediate the increased risk of subsequent DR progression.