A Case of Transient Monocular Vision Loss and Paracentral Acute Middle Maculopathy

A 77-year-old man with multiple cerebrovascular risk factors presented with a history of transient monocular vision loss and residual paracentral visual disturbance in the right eye. Carotid ultrasounds, erythrocyte sedimentation rate, and C-reactive protein were all within normal limits. He was found to have retinal whitening within the macula in the right eye, corresponding to an area of decreased retinal perfusion on optical coherence topography (OCT)-angiography and a hyperreflective middle retina band on spectral domain-OCT. This was consistent with a diagnosis of paracentral acute middle maculopathy (PAMM). PAMM should be considered a part of the differential diagnosis in patients with focal visual disturbances, and OCT studies are recommended as part of the work up as subtle fundus findings may be missed.

Photo and Video Essay Section Editors: Melissa W. Ko, MD Dean M. Ceatari, MD Peter Quiros, MD A Case of Transient Monocular Vision Loss and Paracentral Acute Middle Maculopathy Devin M. Betsch, MD, Amit V. Mishra, MD, Paul R. Freund, MD, FRCSC FIG. 1. Color fundus photography of the right eye centered on the nerve and macula. There is subtle retinal whitening superior to the fovea (arrow). Abstract: A 77-year-old man with multiple cerebrovascular risk factors presented with a history of transient monocular vision loss and residual paracentral visual disturbance in the right eye. Carotid ultrasounds, erythrocyte sedimentation rate, and C-reactive protein were all within normal limits. He was found to have retinal whitening within the macula in the right eye, corresponding to an area of decreased retinal perfusion on optical coherence topography (OCT)-angiography and a hyperreflective middle retina band on spectral domain-OCT. This was consistent with a diagnosis of paracentral acute middle maculopathy (PAMM). PAMM should be considered a part of the differential diagnosis in patients with focal visual disturbances, and Department of Ophthalmology and Visual Sciences, QEII Health Sciences Centre, Halifax, Canada. The authors report no conflicts of interest. Address correspondence to Devin M. Betsch, MD, Department of Ophthalmology and Visual Sciences, QEII Health Sciences Centre, 2035-2 West Victoria Building, 1276 South Park Street, Halifax, NS B3H 2Y9, Canada; E-mail: [e-mail] e360 OCT studies are recommended as part of the work up as subtle fundus findings may be missed. Journal of Neuro-Ophthalmology 2021;41:e360–362 doi: 10.1097/WNO.0000000000001162 © 2020 by North American Neuro-Ophthalmology Society A 77-year-old man was referred for assessment of visual disturbance in the right eye. He reported an episode of transient monocular vision loss described as a “gray curtain” over his entire right visual field lasting 30 minutes. After this episode, he noted a persistent paracentral “fog-like” scotoma. His visual acuity was 20/30 in the right eye and 20/25 in the left. There was no afferent pupillary defect. His anterior segment examination was within normal limits. Dilated retinal examination and color fundus photography showed a subtle area of retinal whitening within the macula of the right eye (Fig. 1). No retinal emboli were appreciated Betsch et al: J Neuro-Ophthalmol 2021; 41: e360-e362 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Photo and Video Essay on examination. The area of retinal whitening corresponded to a well demarcated hyperreflective lesion on en-face optical coherence topography (OCT) (Fig. 2A). OCTangiography (OCT-A) showed an area of decreased retinal perfusion within the macula, consistent with a small branch retinal artery occlusion (Fig. 2B). Spectral domain (SD)OCT showed a discrete hyperreflective band in the superior macula spanning the inner plexiform layer, inner nuclear layer, and outer plexiform layer, consistent with paracentral acute middle maculopathy (PAMM) (Fig. 3A). His medical history was significant for hypertension and dyslipidemia. A computed tomography head and carotid ultrasound were ordered, which were unremarkable. Erythrocyte sedimentation rate and C-reactive protein were also within normal limits. He was started on aspirin and clopidogrel and referred back to his family physician for vascular risk factor optimization. At a 2-month follow-up visit, the patient had noticed a subjective improvement in his blurred central vision in the right eye. His visual acuity was 20/50 in the right eye and 20/25 in the left. Repeat SD-OCT showed focal retinal atrophy in the area of the PAMM lesion (Fig. 3B). PAMM was first described by Sarraf et al in 2013 as a maculopathy characterized on SD-OCT by hyperreflective band-like lesions at the level of the inner nuclear layer (INL) (1). PAMM was initially considered to be a variant of acute macular neuroretinopathy, but PAMM is now considered a distinct process secondary to localized ischemia at the level of the intermediate retinal capillary plexus (1,2). Risk factors for PAMM include use of systemic vasopressors, such as caffeine, oral contraceptives, and phosphodiesterase type 5 inhibitors. This entity has also been described in association with an array of ischemic retinal pathologies, including diabetic retinopathy, central retinal vein occlusion, retinal artery occlusion, and hypertensive retinopathy (2,3). PAMM most often presents in individuals in their late 50s–60s who have known vascular risk factors. However, cases of idiopathic PAMM in young, otherwise healthy individuals have also been documented (2). The most common presenting complaint of patients with PAMM is an acute onset of paracentral scotoma, often without any other ocular or neurologic symptoms. A preceding episode of transient monocular vision loss, as seen in our case, is atypical for PAMM, but consistent with a common underlying etiology of retinal ischemia. PAMM lesions are described as gray to white, smooth, deep retinal lesions in the parafoveal area, which may have visible adjacent emboli. These lesions are frequently very subtle and may be missed on funduscopic examination. Ancillary imaging can help confirm the diagnosis of PAMM with the presence of characteristic SD-OCT findings, including hyper-reflective, placoid bands at the Betsch et al: J Neuro-Ophthalmol 2021; 41: e360-e362 FIG. 2. En-face optical coherence topography (OCT; Heidelberg Spectralis, Heidelberg Engineering, Dossenheim, Germany) (A) and OCT-angiography (OCT-A) (B) of the right eye centered on the macula. The en-face OCT demonstrates an area of hyper-reflectance superior to the fovea (arrow), which corresponds to an area of relative decreased perfusion in the OCT-A deep retinal capillary plexus segmentation (arrow). level of the INL, as were seen in our patient (Fig. 3) (1). OCT-A showed reduced flow of the capillary plexus. Compromise of the middle capillary plexus in particular has been shown to be associated with subsequent atrophy of the INL (4). There is no treatment for PAMM lesions themselves, and management is aimed at identifying and optimizing treatment of risk factors to reduce the risk of subsequent cerebrovascular or cardiovascular events. Occult arterial occlusions can be associated with PAMM, so it is important to order carotid ultrasound and, in age appropriate patients, inflammatory blood work to evaluate for giant cell arteritis. The hyper-reflective PAMM lesion seen on OCT progress FIG. 3. Spectral-domain optical coherence topography (Heidelberg Spectralis) of the right eye on initial presentation (A) and 2 month follow-up (B) of a 77-year-old man with transient vision loss. Figure (A) shows a hyper-reflective band in the superior macula at the level of the inner plexiform layer, inner nuclear layer, and outer plexiform layer (arrow). Figure (B) shows evolution of this lesion into an area of retinal thinning at a 2 month follow-up visit. e361 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Photo and Video Essay to atrophy of the INL over time, but most patients experience partial resolution of the associated scotomas (1). A 2018 study by Bakhoum et al showed that more diffuse PAMM lesions, or those that involved both the inner and middle retina, were correlated with more guarded visual prognosis (5). In summary, we present a case of a 77-year-old gentleman who presented to care after an episode of incompletely resolved transient monocular visual disturbance and was found to have PAMM on SD-OCT with corresponding retinal perfusion deficits on OCT-A. This diagnosis should be considered in individuals who report transient vision loss but do not return to baseline visual acuity or normal visual fields. SD-OCT studies are a very useful investigation to include in the work up of these patients as the funduscopic findings can be subtle and easily overlooked. Once a diagnosis of PAMM is made, a systemic work up to evaluate vascular risk factors and underlying inflammatory etiologies should be initiated. STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: P. R. Freund, A. V. Mishra, and D. M. Betsch; b. Acquisition of data: P. R. Freund, and D. M. Betsch; c. Analysis and interpretation of data: P. R. Freund, A. V. Mishra, and D. M. Betsch. Category 2: a. Drafting the manuscript: P. R. Freund, and D. M. Betsch; b. Revising it for intellectual content: P. R. Freund, e362 A. V. Mishra, and D. M. Betsch. Category 3: a. Final approval of the completed manuscript: P. R. Freund, A. V. Mishra, and D. M. Betsch. ACKNOWLEDGMENT The authors thank the patient for granting permission to submit this case for publication. REFERENCES 1. Sarraf D, Rahimy E, Fawzi AA, Sohn E, Barbazetto I, Zacks DN, Mittra RA, Klancnik JM Jr, Mrejen S, Goldberg NR, Beardsley R, Sorenson JA, Freund KB. Paracentral acute middle maculopathy: a new variant of acute macular neuroretinopathy associated with retinal capillary ischemia. JAMA Ophthalmol. 2013;131:1275– 1287. 2. Rahimy E, Kuehlewein L, Sadda SR, Sarraf D. Paracentral acute middle maculopathy: what we knew then and what we know now. Retina. 2015;35:1921–1930. 3. Sebastiani S, Pellegrini M, Giannaccare G, Sarraf D. Paracentral acute middle maculopathy associated with phosphodiesterase-5 inhibitor therapy. Retin Cases Brief Rep. 2018;5:1–4. 4. Shah A, Rishi P, Chendilnathan C, Kumari S. OCT angiography features of paracentral acute middle maculopathy. Indian J Ophthalmol. 2019;67:417–419. 5. Bakhoum MF, Freund KB, Dolz-Marco R, Leong BCS, Baumal CR, Duker JS, Sarraf D. Paracentral acute middle maculopathy and the ischemic cascade associated with retinal vascular occlusion. Am J Ophthalmol. 2018;195:143–153. Betsch et al: J Neuro-Ophthalmol 2021; 41: e360-e362 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.