Author: Racem Choura (Tunisia)
Co-authors: Rahma Saidane, Asma Khallouli, Dhouha Gouider, Ahmed Arfaoui, Afef Maalej, Riadh Rannen
Purpose
To evaluate the relevance of optical coherence tomography angiography (OCT-A) in assessing early microvascular changes in eyes of diabetic individuals without clinical retinopathy.
Setting/Venue
A monocentric observational prospective study conducted in the Department of Ophthalmology of the Military Hospital of Tunis, Tunisia.
Methods
We conducted a monocentric observational prospective study including 48 eyes of 29 patients with type 2 diabetes mellitus and 52 control eyes of 26 age-matched healthy subjects. All included individuals underwent a complete ophthalmic examination and OCT-A scans 6x6 mm (Optovue RTVue-XR Avanti, AngioVue) between September 2020 and February 2021. Eyes with existing retinal, vitreoretinal interface, optic nerve diseases or/and with poor-quality images were excluded. We assessed the size and the regularity of the foveal avascular zone (FAZ) as well as vessel beading, capillary non-perfusion, microaneurysms and vessel density (VD) in the superficial and the deep layers.
Results
Foveal avascular zone size measured 0.321 mm2 (0.124–0.593) in eyes of diabetic patients and 0.291 mm2 (0.117–0.489) in control eyes (p = 0.03). Foveal avascular zone irregularity was seen more often in diabetic than control eyes (35.4% and 7.7%, respectively; p = 0.008). Capillary non-perfusion was noted in 27.1% of diabetic patients' eyes and 3.8% of control eyes (p = 0.02). Microaneurysms and venous beading were noted in less than 8% of both diabetic and control eyes. On univariate analysis, whole and parafoveal vessel densities in the superficial capillary plexus (SCP) and the deep capillary plexus (DCP) were found to be associated with diabetes (Whole SCP density p = 0.031, Parafoveal SCP density p = 0.024, Whole DCP density p = 0.019, Parafoveal DCP density p = 0.006). We did not need to perform multivariate analysis in view of the comparability between diabetic patients and control subjects.
Conlusions
Optical Coherence Tomography Angiography showed a noteworthy relevance in assessing foveal microvascular changes undetected by fundus examination in diabetic patients. Foveal avascular zone abnormalities, capillary non-perfusion and decrease in parafoveal vessel density especially in the deep layers may be considered as early retinal changes in diabetic patients. Although OCT-Angiography is a valuable non-invasive imaging tool, various artifacts caused by OCT image acquisition, intrinsic eye characteristics, motion, processing, and display strategies are to be considered. Therefore, special attention is required for interpretation of images, as artifacts may interfere with the diagnosis, classification, or measurement of lesions in OCT-A images.
Financial Disclosure
The authors declare no conflict of interest.
Comments
-
