Abstract
Purpose :
Type 1 Diabetes Mellitus (T1DM) is a lifelong autoimmune disease that places individuals at risk for macrovascular as well as microvascular complications such as diabetic retinopathy (DR) which may lead to vision loss. Foveal Density (FD), which takes into consideration vascular branching complexity, may be a better indication of retina health than Foveal Avascular Zone (FAZ), a standard currently used.
Methods :
Data from 122 subjects (8-78 years, 33% male) (109 T1DM, 13 non-T1DM) collected over a period of up to 5 years (2015-19). Demographics included age, onset of DM, and self-reported HbA1c. Measurements of the FAZ and FD were calculated from 3mm x 3mm scans with the Optovue AngioVue HD on the RTVue XR Avanti OCTA (Fremont, CA). Statistical analyses included linear regression, multivariable linear regression, and paired T test, completed in SPSS.
Results :
Significant negative correlation was found between duration of diabetes and FD OU (p=.00039) with no correlation found with FAZ OU (p=.60), insulin pump use, duration of pump use, or onset of T1DM. We noted significant negative correlation between average HbA1c and FD OU (p=.010) compared to FAZ OU (p=.95). Mean FAZ and FD for non T1DM subjects were .281 and 50.8, respectively, mean FAZ and FD for T1DM were .238 and 49.2. No significant difference was found in either FAZ or FD between T1DM/non-T1DM groups (FAZ p=.129, FD p=.069). In a subgroup of 12 (75% T1DM, age 17-72 years) subjects for which we had FAD and FZ measurements spanning 5 years, there was statistically significant decline found in FD OU over that period (p=.006) with no correlating statistically significant trend found in FAZ OU (p=.06).
Conclusions :
While FD and FAZ have a close correlation, FD may be a more accurate representation of retinal health due to vascular branching complexity rather than measurement of the vascular margins. This demonstrates that FD is inversely proportional to HbA1c, suggesting vascular branching is more sensitive to tight glycemic control than expansion of the FAZ. Duration of diabetes was also identified as a possible influencer of declining FD in retinal health. Decline in FD has been reported in worsening retinal outcomes, making OCTA a valuable tool in assessing retinal health in both T1DM and non-T1DM populations. Baseline OCTA measurements at onset of T1DM management should be an integral part of routine ophthalmic care.
This is a 2021 ARVO Annual Meeting abstract.