Paracentral Acute Middle Maculopathy

Abstract

IMPORTANCE With the advent of more sophisticated imaging systems, such as spectral domain optical coherence tomography (SD-OCT), disruption of the inner segment/outer segment (IS/OS) band, and thinning of the outer nuclear layer (ONL) have been identified in association with acute macular neuroretinopathy (AMN). OBJECTIVES To characterize a new SD-OCT presentation of AMN as a paracentral acute middle maculopathy and to describe multimodal imaging findings that implicate an underlying pathogenesis related to retinal capillary ischemia. DESIGN, SETTING, AND PARTICIPANTS Retrospective observational case series (January 1, 2012, to January 1, 2013) reviewing clinical and imaging data from 9 patients (11 eyes) with AMN at 6 tertiary referral centers. Lesions were classified as type 1 or 2 in relation to the SD-OCT location of the lesion above (type 1) or below (type 2) the outer plexiform layer (OPL) at 6 tertiary referral centers. RESULTS Of the 9 patients, 5 were female and 4 were male (mean age, 47.6 years; range, 21-65 years). All patients presented with an acute paracentral scotoma and demonstrated a classic dark gray paracentral lesion with near-infrared imaging. Visual acuity ranged from 20/15 to 20/30. Six eyes (5 patients) had type 1 SD-OCT lesions, also referred to as paracentral acute middle maculopathy, and 5 eyes (4 patients) had type 2 SD-OCT lesions. Although type 1 lesions lead to inner nuclear layer (INL) thinning, type 2 lesions resulted in ONL thinning. Type 2 lesions were always associated with significant outer macular defects, including disruption of the inner segment/outer segment and outer segment/retinal pigment epithelium bands, whereas type 1 lesions spared the outer macula. CONCLUSIONS AND RELEVANCE Paracentral acute middle maculopathy may represent a novel variant of AMN that affects the middle layers of the macula above the OPL as diagnosed with SD-OCT imaging. Two types of AMN lesions may be seen with SD-OCT occurring above and below the OPL. Type 1 refers to hyperreflective bands in the OPL/INL region with subsequent INL thinning. Type 2 is hyperreflective bands in the OPL/ONL region with subsequent ONL thinning. Type 2 lesions may be associated with concomitant defects of the inner segment/outer segment layer. We propose that each of these lesions may be explained by occlusion of either the superficial capillary plexus (type 1) or deep capillary plexus (type 2) located in the innermost and outermost portion of the INL, respectively, immediately adjacent to each corresponding lesion type.

Characterization of the Middle Capillary Plexus Using Optical Coherence Tomography Angiography in Healthy and Diabetic Eyes

“…34 PAMM lesions were originally proposed to be the result of ischemia of the SCP, 34 but consideration of the anatomical location of the MCP immediately superficial to PAMM lesions suggests more likely involvement of this plexus. 35 Further emphasizing the importance of improved segmentation of MCP, recent case studies of PAMM imaged using OCTA have demonstrated attenuated blood flow of the DCP.…”

Optical Coherence Tomography Angiography of Acute Macular Neuroretinopathy and Paracentral Acute Middle Maculopathy

“…5 This case appears unique as a type 1 PAMM lesion, as prior cases were mostly seen in older males. 1 Previously described AMN/PAMM cases were related to hypertensive- or vasoconstrictive-inducing substances. In this case, the combined hypotension/anemia as well as hypercoagulable state of pregnancy may have contributed to the ischemic event.…”

“…AMN has been associated with vasoconstrictors and sympathomimetics. 1 In 2013, paracentral acute middle maculopathy (PAMM) was described as an AMN variant, seen as a hyperreflective band involving the middle retinal layers on spectral-domain optical coherence tomography (SD-OCT). 1 Type 1 PAMM lesions involve layers above the outer plexiform layer (OPL), reflecting superficial or intermediate capillary plexus occlusion; type 2 lesions involve layers below the OPL, affecting the deep capillary plexus.…”

“…1 Type 1 PAMM lesions involve layers above the outer plexiform layer (OPL), reflecting superficial or intermediate capillary plexus occlusion; type 2 lesions involve layers below the OPL, affecting the deep capillary plexus. 1 …”

Sudden-Onset Paracentral Vision Loss

“…4–6 The PAMM lesions, associated with retinal vascular disease, may resolve and lead to retinal thinning and paracentral scotomas. 6 …”