Microcystic macular edema in optic nerve atrophy: case series

Abstract

AbstractPurpose Microcystic macular edema (MME) is a new entity defined as lacunar areas of hyporeflectivity in the retinal inner nuclear layer after severe optic neuropathy (ON). Initially, MME was fortuitously discovered in optic neuritis.Methods From July 2013, we imaged all patients with ON by SD OCT. Retinal nerve fiber layer thickness (RNFLT), macular cube thickness (MCT) and retinal ganglion cell layer thickness (RGCLT) were assessed. Studied parameters included also the delay between onset of ON and detection of MME and correlation of the visual field defect to the MME topography.Results Sixteeen patients (19 eyes) exhibited MME. Etiologies of ON were compressive (7), degenerative (4), inflammatory (3), ischemic (1), and hereditary (1). There were 9 women and 7 men, mean age at diagnosis being 34.1 years. Visual acuity ranged from NLP to 12/10 (median 4/10). Mean RNFLT was 61.6µm [97+/‐10µm], mean MCT 271.37µm [261+/‐18µm] and mean RGCLT 57.22µm [82+/‐7µm]. The time from diagnosis until MME detection ranged from 4 months to 23 years. A good correlation was found between the zone of retinal atrophy on infrared photography and MME distribution. However, only 4/16 visual field defects correlated to the MME topography.Conclusion MME can occur as early as 4 months after ON (ocular trauma in our series) and can persist as late as 23 years after the onset of ON. MME is not only related to inflammatory ON, as postulated initially, but is a nonspecific manifestation from ON of any etiology. The precise mechanism leading to MME is unknown but trans‐synaptic retrograde degeneration is likely. Why only 10% of patients with ON exhibit MME is unknown, but MME might be a transient phenomenon. Further clinical and experimental studies are needed to answer these questions.