# Comparison of the Usefulness of Optical Coherence Tomography Angiography and Fluorescein Angiography in the Diagnosis of Diabetic Macular Edema

## TL;DR

This study compares two imaging techniques for diagnosing diabetic macular edema and finds that OCTA is useful for assessing macular ischemia but less effective at detecting microaneurysms compared to FA.

## Contribution

The study provides a direct comparison of OCTA and FA diagnostic performance in diabetic macular edema.

## Key findings

- FAZ size in deep plexus OCTA closely correlates with FA measurements.
- OCTA detects fewer microaneurysms than FA in DME patients.
- Poor glycemic control is linked to a higher incidence of microaneurysms.

## Abstract

Background/Objectives: Diabetic macular edema (DME) is the primary cause of vision loss in people with diabetes, and if untreated, it can result in irreversible macular damage. Both fluorescein angiography (FA), the gold standard, and optical coherence tomography angiography (OCTA) are used for evaluation of this disease. The objective of this study was to compare the diagnostic value of both. Methods: We conducted a comparative analysis of 98 patients aged 18–80 years with significant DME and best-corrected visual acuity ≥0.1 according to the Snellen chart. Participants underwent glycated hemoglobin blood test (HbA1c) and ophthalmological examinations, including OCTA and FA. OCTA 3 × 3 mm scans of superficial (SCP) and deep capillary plexus (DCP) along with FA scans were exported to the Gimp computer program. Size of the foveal avascular zone (FAZ), the number of visible microaneurysms (MAs), and ETDRS report number 11 classification of the images were assessed. Results: FAZ size differed significantly in superficial plexus (0.41 mm2), deep plexus (0.43 mm2) OCTA, and FA (0.38 mm2) (p < 0.001). FAZ size in DCP OCTA closely correlated with that of FA (τ = 0.79, p < 0.001). The total number of MAs visualized in the OCTA was significantly lower than in FA (p < 0.001). ETDRS classification of scans revealed that the level of consistency between the examinations was moderate to very strong. Conclusions: OCTA may be useful in evaluating macular ischemia. It is less sensitive in detecting MAs in DME eyes. FAZ has sharper boundaries and is larger when measured in OCTA. Poor glycemic control results in higher incidence of MAs in macula.