Vascular Microanatomy of Small Resolved Paracentral Acute Middle Maculopathy Lesions

To study microvascular characteristics of small resolved paracentral acute middle maculopathy (PAMM) lesions in fellow eyes of patients with unilateral retinal vein occlusion (RVO).

Prospective cross-sectional study.

Patients with prior unilateral branch or central RVO and OCT evidence of resolved PAMM in the fellow, otherwise normal, eye were recruited prospectively and imaged with OCT angiography (OCTA).

The resolved PAMM lesions were identified as focal areas of inner nuclear layer thinning over an anteriorly displaced outer plexiform layer (OPL). En face OCTA projections showing the location and size of the resolved PAMM lesions were created using 2 OPL segmentation lines with -9-μm and 0-μm offsets, and the cumulative distribution was evaluated. Anterior to the resolved PAMM lesions, vessels in the superficial vascular plexus were traced to identify small arterioles supplying the affected areas.

Cumulative spatial distribution on small resolved PAMM lesions.

From 24 fellow eyes of 24 patients with unilateral RVO (15 men and 9 women; mean age, 62.1 ± 13.6 years), 152 resolved PAMM lesions were identified. Of these lesions, 130 (85.5%) were found within the perifoveal region, and only 12 (7.9%) were found within the temporal quadrant. Of 28 lesions analyzed, the arteriole supplying the affected area was a single side branch of a larger vessel, with only 3 supplied by a terminal branch.

Small resolved PAMM lesions in fellow eyes of patients with unilateral RVO are most prevalent in perifoveal regions supplied by side branches of low-order retinal arteries.