Abstract
Aim To investigate the incidence and clinical characteristics of paracentral acute middle maculopathy (PAMM) and its relationship with prominent middle limiting membrane (p-MLM) sign in eyes with retinal artery occlusion (RAO) or retinal vein occlusion (RVO) in a Chinese clinical setting. Methods In this retrospective observational study from January 2015 to May 2020, multimodal imaging data of 807 eyes including 555 consecutive patients with RVO or 252 consecutive patients with RAO were reviewed. All patients were scanned using the spectrum-domain optical coherence tomography (OCT), and some of them underwent color fundus photography, fundus fluorescence angiography, en face OCT, and OCT angiography. Results PAMM was detected in 49 eyes of 49 RAO patients and 29 eyes of 29 RVO patients. The mean ages at presentation were 64.49 ± 13.90 years and 54.00 ± 18.48 years in RAO and RVO patients (P=0.006), respectively. Eyes with RAO were more prone to develop PAMM (19.44% [49/252] vs. 5.23% [29/555]; P < 0.001). Of the 78 eyes with PAMM, 24 eyes (7 eyes with RVO and 17 eyes with RAO) were found with p-MLM sign. An interesting phenomenon that had been overlooked before was that the hyperreflective line of the p-MLM sign was usually continuous, regardless of the type of PAMM lesion. Conclusions This series is the largest to date to describe the clinical characteristics of PAMM and p-MLM sign in Chinese patients. The incidence of PAMM and p-MLM sign in patients with RAO was relatively higher than that in patients with RVO. These signs alone probably represent milder ischemia and prompt us to carry out a comprehensive and meticulous examination to prevent the further development of the disease. In addition, the hyperreflective line of the p-MLM sign was usually continuous, which could support the totally venous nature of the retinal deep capillary plexus to some extent.
Highlights
Paracentral acute middle maculopathy (PAMM), which was first defined by Sarraf et al in 2013, is characterized by the presence of a hyperreflective band spanning the inner nuclear layer (INL) with subsequent permanent INL thinning [1]
In 2013, Chu et al [11, 12] introduced the “prominent middle limiting membrane (p-MLM) sign,” a hyperreflective line in the inner synaptic portion of the outer plexiform layer (OPL) on spectral-domain optical coherence tomography (SD-OCT) B-scan images, as an indicator of acute ischemic retinal damage in retinal artery occlusion (RAO) and diagnostic tool to distinguish ischemic from the nonischemic retinal vein occlusion (RVO). e pathogenesis of the p-MLM sign is similar to that of PAMM; the relationship between them is poorly investigated
Multiple imaging scans were reviewed for a total of 807 consecutive eyes of 807 patients, including 252 eyes with RAO (143 central RAO, 105 branch RAO, and four cilioretinal artery occlusion only) and 555 eyes with RVO (226 central RVO (CRVO) and 329 branch RVO)
Summary
Paracentral acute middle maculopathy (PAMM), which was first defined by Sarraf et al in 2013, is characterized by the presence of a hyperreflective band spanning the inner nuclear layer (INL) with subsequent permanent INL thinning [1]. It is being increasingly reported and demonstrated not to be a distinct entity but a common sign of several ocular diseases [2], uneventful ocular surgeries [3, 4], or even systemic diseases [5,6,7]. No large-scale study has reported the prevalence or clinical characteristics of PAMM in Chinese patients with RVO or RAO, a few case reports and small case series exist [21,22,23]
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