A recent study published in Ophthalmic Research evaluated the clinical utility of adjunctive optical coherence tomography angiography (OCT-A) to detect and diagnose diabetic retinopathy (DR) with ultra widefield color photography (UWF-CP) and UWF fluorescein angiography (UWF-FA).
Talk about the study first.
In this cross-sectional, prospective study, investigators performed mydriatic UWF-CP, UWF-FA, and OCT-A on 114 eyes from 57 diabetic patients and subsequently assessed DR severity.
Leveraging UWF-CP, the level of DR was graded using previously validated protocols with consideration given to both the number and extent of retinal lesions.
While ischemic regions were identified on UWF-FA, ImageJ software was used to calculate the nonperfusion index (NPI) in square millimeters via dividing the nonperfusion area (NPA) by the total gradable area (TA).
Expand on this ImageJ.
ImageJ is a Java-based image processing program that was developed at the National Institutes of Health (NIH) and the Laboratory for Optical and Computational Instrumentation (LOCI).
What else?
Utilizing a similar method, the amount and extent of involvement of rods (rod nonperfusion index [RPI]) and cones (cone nonperfusion index [CPI]) were calculated.
And the patient criteria?
Due to non-DR findings or previous laser photocoagulation, 45 eyes were excluded from the study, resulting in 69 eyes that were analyzed.
Findings?
The study authors found that DR severity was linked with larger NPI, even after distinguishing between cones and rods.
Further, in eyes with nonproliferative DR (NPDR), NPI was correlated with diabetic macular edema (DME) and central subfield thickness (CST).
What did UWF-FA show?
UWF-FA macular nonperfusion correlated with all three measures including NPI, RPI, and CPI.
Central superficial capillary plexus vessel density (VD) and vessel perfusion (VP) correlated with the presence of DME and CST.
Anything else?
Central VD and VP corresponded with macular nonperfusion in eyes with NPDR, and a larger foveal avascular zone (FAZ) area was associated with decreased central VD and decreased central VP.
Based on these results, nonperfusion found on UWF-FA is correlated with DR severity and DME, and OCT-A imaging of the superficial capillary plexus correlated with the incidence of DME and macular ischemia.
Expert opinion?
The study authors concluded that each of these imaging modalities “provide[s] clues on the pathogenesis and progression pattern of [DR] and [DME] from which insights on clinical decision-making can be drawn.”
Take home.
All three imaging modalities (OCT-A, UWF-CP, and UWF-FA) could provide diagnostic findings with relevant clinical information of interest to eyecare practitioners for patients suffering from DR.