Perivenular Capillary Rarefaction in Diabetic Retinopathy: Interdevice Characterization and Association to Clinical Staging.

Purpose: Geometric perfusion deficit (GPD) is a newly described OCT angiography (OCTA) parameter identifying the total area of presumed retinal ischemia. The aim of our study is to characterize differences in GPD and other common quantitative OCTA parameters between macular full field, perivenular zones, and periarteriolar zones for each clinical stage of nonproliferative diabetic retinopathy (DR) and to assess the influence of ultrahigh-speed acquisition and averaging on the described differences. Design: Prospective observational study. Participants: Forty-nine patients, including 11 (22.4%) with no sign of DR, 12 (24.5%) with mild DR, 13 (26.5%) with moderate DR, and 13 (26.5%) with severe DR. Patients with diabetic macular edema, proliferative DR, media opacity, head tremor, and overlapping retinal diseases or systemic diseases influencing OCTA were excluded. Methods: OCT angiography was performed 3 times for each patient: 1 using Solix Fullrange single volume (V1) mode, 1 using Solix Fullrange 4 volumes mode with automatically averaged scan (V4), and 1 using AngioVue. Main Outcome Measures: Full macular, periarteriolar, and perivenular perfusion density (PD), vessel length density (VLD), vessel density index, and GPD for both the superficial capillary plexus (SCP) and deep capillary plexus (DCP). Results: In patients showing no sign of DR, PD and VLD were significantly lower in the perivenular area in both the DCP and SCP using V1 and V4, whereas GPD was significantly higher in the perivenular zone in the DCP and SCP with all 3 devices. In patients with mild DR, all 3 measurements (PD, VLD, and GPD) were significantly different in the perivenular zone with all 3 devices. In patients with moderate DR, PD and VLD were lower in the DCP and SCP when measured with V1 and V4. Moreover, GPD was higher in the perivenular zone in the DCP with all 3 devices, whereas only V4 detected a difference in the SCP. In severe DR, only V4 detected a lower PD and VLD and a higher GPD in the DCP of the perivenular zone. V4 also detected a higher GPD in the SCP. Conclusions: Geometric perfusion deficit highlights prevalent perivenular location of macular capillary ischemia in all stages of DR. In severe DR patients, only averaging technology allows detection of the same finding. Financial Disclosures: The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Paracentral acute middle maculopathy following internal carotid artery stenting.

Purpose: To report a case of paracentral acute middle maculopathy (PAMM) that presented after internal carotid artery stenting despite the use of a filter embolic protection device. Observations: A 74-year-old man presented one week following transfemoral stenting of the right internal carotid artery for high-grade stenosis. A filter-type embolic protection device was used during the stenting procedure to prevent distal embolization of atherosclerotic debris. Dilated examination of the right eye revealed a parafoveal gray lesion in the macula and optical coherence tomography showed a corresponding placoid hyperreflective band at the level of the inner nuclear layer consistent with PAMM. The patient was asymptomatic. At 10 weeks follow up the PAMM lesion was resolved. Conclusions: PAMM occurred following internal carotid artery stenting despite the use of a filter embolic protection device, likely due to embolic debris passing through the filter device or debris released while the filter was in a collapsed state. The PAMM lesion was small and resolved without visual sequelae.

Paracentral acute middle maculopathy-review of the literature.

Paracentral acute middle maculopathy (PAMM) is a recently identified spectral-domain optical coherence tomography (SD-OCT) finding characterized by a hyper-reflective band spanning the inner nuclear layer (INL), which typically evolves to INL atrophy in later stages. Typical clinical features include the sudden onset of one or multiple paracentral scotomas, normal or mild reduction in visual acuity, and a normal fundus appearance or a fundus with a deep grayish lesion. Although its pathophysiology is not yet fully understood, ischemia at the level of the intermediate and deep capillary plexa has been demonstrated to play a major role. Since its first description, an increasing number of publications on PAMM have been published in ophthalmology scientific journals. The purpose of this study is to provide a review of the current literature on PAMM.

Paracentral acute middle maculopathy as a cause of unexplained visual loss in central retinal vein occlusion.

A 79-year-old man presented with unilateral unexplained sudden onset visual loss in the setting of central retinal vein occlusion (CRVO). Non ischemic CRVO in the right eye (RE) was confirmed on fluorescein angiography. Spectral domain optical coherence tomography (SD-OCT) showed absence of macular edema and hyperreflective band-like lesions in the middle retinal layers of the RE suggesting a diagnosis of paracentral acute middle maculopathy (PAMM). Patient was observed and after 3 months, best-corrected visual acuity in the RE spontaneously improved from 38 to 56 ETDRS letters. SD-OCT scans showed thinning of the inner nuclear layer of the RE. OCT angiography in the RE revealed a mild attenuation of the vascular flow signal in the superficial capillary plexus and patchy areas of vascular flow void in the deep capillary plexus, as compared to the fellow eye. The present case outlines the importance of recognising PAMM as a cause of unexplained visual loss. In the setting of a CRVO with sudden vision loss and absence of macular edema, clinicians should pay attention to any hyperreflectivity and/or to thinning of the middle retinal layers on SD-OCT.

Management of Deep Retinal Capillary Ischemia by Electromagnetic Stimulation and Platelet-Rich Plasma: Preliminary Clinical Results.

INTRODUCTION: To investigate the efficacy of retinal electromagnetic stimulation and sub-tenon autologous platelet-rich plasma in the treatment of deep retinal capillary ischemia. METHODS: The study included 28 eyes of 17 patients aged 15-76 years (mean 37.9 years) who had deep retinal capillary ischemia. Patients who had acute-onset paracentral scotoma in the last 1 month were included in the study between January 2018 and January 2019. The diagnosis of deep retinal capillary ischemia was based on clinical history and typical findings of optical coherence tomography angiography. The eyes were divided into three groups: group 1 (n = 7 eyes) received electromagnetic stimulation alone; group 2 (n = 7 eyes) received electromagnetic stimulation and sub-tenon autologous platelet-rich plasma injection; group 3 had no intervention and served as a control group (n = 14 eyes). The patients underwent ten sessions of electromagnetic stimulation in groups 1 and 2. Sub-tenon autologous platelet-rich plasma injection was performed immediately after the first, fifth, and tenth sessions of electromagnetic stimulation in group 2. The deep retinal capillary density and best corrected visual acuity changes were investigated before and after treatment at the first month. RESULTS: The mean deep retinal capillary density was 52.0% before electromagnetic stimulation and 56.1% after ten sessions of application in group 1; this improvement was statistically significant (p = 0.01). In the combined treatment group (group 2), the mean deep retinal capillary density was 46.9% before the treatment and 56.5% after the treatment; this increase was also statistically significant (p = 0.01). Statistically significant best corrected visual acuity improvement (p = 0.01) could be achieved only in group 2. The combined treatment was significantly superior (p < 0.01) to treatment with only electromagnetic stimulation regarding best corrected visual acuity and deep retinal capillary density. In the control group (group 3), there was no statistically significant change (p = 0.09) in the mean deep retinal capillary density and best corrected visual acuity. CONCLUSION: Treatment of the underlying cause is a priority in the treatment of deep retinal capillary ischemia. However, in the acute period, local ischemia treatment is necessary to prevent permanent retinal damage and scotomas. In mild cases, only electromagnetic stimulation, which is non-invasive and easy to use, might have a beneficial effect on deep retinal capillary density. In more severe cases, sub-tenon fresh autologous platelet-rich plasma injection together with electromagnetic stimulation may be more effective in the treatment of local ischemia of the retina in order to augment the response. FUNDING: The Rapid Service Fees were funded by the Ankara University Tecnopolis Institute. CLINICAL TRIAL REGISTRATION: titck.gov.tr identifier, 2018-136.

Acute macular neuroretinopathy: A comprehensive review of the literature.

Acute macular neuroretinopathy is a relatively rare condition originally defined by the presence of intraretinal, reddish-brown, wedge-shaped lesions, the apices of which tend to point toward the fovea. Acute onset of paracentral scotomas corresponding to the clinically evident lesions is both common and characteristic. Although the pathogenesis of acute macular neuroretinopathy is complex, recent research suggests a microvascular etiology. Advances in multimodal imaging have enabled better characterization of this retinal disorder and have led to newly proposed diagnostic criteria. We review 101 reported cases in the English and non-English language literature identified from 1975, when acute macular neuroretinopathy was first described, to December, 2014. We discuss common risk factors, demographic and clinical characteristics, and multimodal imaging findings, which together provide insights into pathogenesis and guide areas of future investigation.