Abstract
Purpose :
Diabetes can have profound effects on vision through changes to the neurons and vasculature in the retina. To prevent these vision threatening changes, such as diabetic retinopathy and edema, early detection of retinal changes is key. One potential biomarker for early change in the retina is alteration in retinal oximetry. The purpose of this study is to characterize differences in retinal tissue oximetry and superficial vascular density in controls and subjects with type 2 diabetes without retinopathy (DM).
Methods :
36 subjects (51.5 ± 9 years) participated in this study; 19 controls and 17 DM with no retinopathy. Duration of DM was noted for all DM subjects. Testing included HbA1c testing (Siemens) and retinal oximetry (Zilia) measurements of the right eye, within the macula at 3.1 degrees from the fovea; with one measurement sup/temp, inf/temp, sup/nasal, inf/nasal, which were averaged together. Also, OCTA imaging (Zeiss Cirrus) was completed, once available, with OCTA completed on 26 of the 36 subjects. Superficial vascular plexus (SVP) slabs were analyzed with ImageJ for density and compared between groups and correlated with oximetry metrics. Foveal avascular zone was measured and considered in SVP analysis.
Results :
In DM subjects, increased duration of disease was associated with increased oximetry (p = 0.038), but duration was not associated with vessel density changes (p = 0.351). Decreased vessel density was associated with increased retinal oximetry overall (p = 0.036). There was no correlation with HbA1c and oximetry in controls and DM (p = 0.244, p = 0.832, respectively) or HbA1c and SVP density in either group (p = 0.957, p = 0.786). FAZ was controlled for in density measures and not statistically different between groups (p = 0.58).
Conclusions :
These data suggest that retinal tissue oximetry appears to be correlated to duration of disease in subjects with DM without retinopathy. This may be related to changes in vessel density. This pairs well with literature that has shown duration is also associated with retinopathy development. These data suggest oximetry measurements may be a useful subclinical biomarker in predicting impending retinopathy, but more follow up in longitudinal work is needed.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.