PAMM may be a diagnostic marker of arteritic anterior ischemic optic neuropathy
The presence of paracentral acute middle maculopathy (PAMM) on OCT scans appears to be a highly specific test for arteritic anterior ischemic optic neuropathy (arteritic-AION) with a high positive predictive value. However, sensitivity is limited.
This retrospective, cross-sectional study evaluated 45 patients diagnosed with anterior ischemic optic neuropathy; 17 had arteritic-AION and 28 had nonarteritic-AION. Macular spectral domain OCT (SD-OCT) imaging was used to detect the presence of PAMM, and these findings were then compared between the two patient groups.
Macular SD-OCT revealed PAMM in 4 eyes, all of which were in the arteritic-AION group, revealing 100% specificity of PAMM for detecting arteritic-AION (95% IC, 88.06%–100%) and a 100% positive predictive value. However, the sensitivity of PAMM for detecting arteritic-AION was only 19.1% (95% IC, 5.5–42.0).
The study is limited by its small sample size and heterogeneity in regard to patient factors, including comorbid ocular and systemic diagnoses (e.g., diabetic retinopathy and carotid stenosis). Larger-scale, adequately powered studies are necessary to better qualify the sensitivity and specificity of macular OCT–identified PAMM in the diagnosis of arteritic-AION.
Arteritic-AION secondary to giant cell arteritis (GCA) requires urgent diagnosis and treatment. In this study, PAMM appears to be a highly specific test for the detection of arteritic-AION, with SD-OCT diagnosing 23.5% of arteritic-AION cases on the basis of PAMM alone with no false positives. Therefore, using macular SD-OCT to evaluate the presence of PAMM should be considered for AION work-up to aid in prompt diagnosis of arteritic-AION and GCA.
Dr. Ali Khan discloses financial relationships with Allergan, Apellis Pharmaceuticals, Genentech (Consultant/Advisor); Regeneron Pharmaceuticals (Grant Support).