Researchers did this study to compare MA counts using UWF-CI and UWF-FA.

The present study is a retrospective study, including patients with type 1 or 2 diabetes mellitus receiving UWF-FA and UWF-CI within two weeks. MAs were manually counted in individual ETDRS and extended UWF zones. Fields with MAs ≥20 DR severity.

In 193 patients, 2.4% had no DR, 29.9% mild non-proliferative DR, 32.6% moderate, 22.9% severe NPDR, and 12.2% proliferative DR. In ETDRS fields, DR severity agreement increased from k=0.346 to 0.600 when dividing UWF-FA counts by a factor of 3, followed by a rapid decline in agreement after that. Total UWF area agreement increased from k=0.317 to 0.565 with an adjustment factor of either 4 or 5.

The study concluded that UWF-FA detects threefold to fivefold more MAs than UWF-CI and identifies 1.6–3.5-fold more fields affecting DR severity. Differences exist at all DR severity levels, thus limiting direct comparison between the modalities. However, correcting UWF-FA MA counts substantially improves DR severity agreement between the modalities.

Reference: https://bjo.bmj.com/content/104/12/1762