Aim To describe the optical coherence tomography angiography (OCT-A) features of patients affected by acute macular neuroretinopathy (AMN).
Methods This is a prospective, observational, cross-sectional study. Multimodal imaging, including spectral domain OCT (Spectralis HRA+OCT; Heidelberg Engineering, Heidelberg, Germany) and 6×6 mm swept source OCT-A (ZEISS PLEX Elite 9000; ZEISS, Dublin, California), was performed on all patients. The primary outcome measure was assessment of the vascular alterations of the superficial (SCP) and deep (DCP) capillary plexuses and choriocapillaris (CC). A segmentation of the AMN lesions using enface OCT images of photoreceptors-retinal pigment epithelium complex was used to discriminate intralesional and extralesional regions on the OCT-A enface slabs of the DCP and CC reconstructions. Each OCT-A slab was imported into ImageJ V.1.50 and digitally binarised for quantitative analyses.
Results Overall, seven patients (mean age 19.4±3.2 years, six women) affected by AMN were included. The mean best-corrected visual acuity was 0.00±0.00 logarithm of the minimum angle of resolution. Twelve healthy age-matched subjects (mean age 22±3.4 years, 10 women) represented the control group. The quantitative analysis of global vessel densities showed that the CC vessel density was significantly lower in patients with AMN (0.495±0.03) compared with the age-matched controls (0.545±0.02) (corrected p=0.0003). The intralesional vessel density of the DCP was 0.349±0.04 in AMN and vs 0.497±0.02 in the controls (corrected p=0.0002).
Conclusions Our study confirmed inner choroidal vascular flow void as a possible pathogenetic mechanism of AMN. We also found a focal impairment of the DCP within the AMN lesions. Future studies are needed to clarify which is the primary location of the vascular insult in this condition.
- en-face optical coherence tomography
- near-infrared reflectance imaging
- optical coherence tomography angiography.
- acute macular neuroretinopathy
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Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Ethics approval The protocol was approved by the Institutional Review Board of San Raffaele Hospital, and the procedures adhered to the tenets of the Declaration of Helsinki.
Provenance and peer review Not commissioned; externally peer reviewed.
Contributors All authors contributed substantially to this manuscript and approved the current version. GC and AA contributed equally and should be both considered as first author. Study design: GC, AA, MBP. Data acquisition: GC, AA, FR. Data interpretation: GC, AA, MRM, MBP, FB. Writing the manuscript: GC, AA, MRM, MBP. Statistical analysis: AA, FR. Critical review and approval of the manuscript: GC, MRM, MBP, FB.
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