Acute macular neuroretinopathy: long-term insights revealed by multimodal imaging.

PURPOSE: To report the structural and functional changes in acute macular neuroretinopathy (AMN) and their long-term evolution. Multimodal retinal imaging was acquired, including Fourier domain optical coherence tomography (OCT), infrared (IR) reflectance, and near IR autofluorescence (NIA). METHODS: In this retrospective observational case series, detailed clinical history and multimodal imaging are reported in eight patients with AMN. Manual segmentation of the Fourier domain OCT volume scans was done in one patient with the largest AMN lesion to yield retinal sublayer topographic maps. RESULTS: Two patients were seen within the first 1 to 2 days of symptoms, and both showed outer nuclear and outer plexiform layer hyperreflectivity. Both patients developed enlargement of the lesion over the first week on IR reflectance imaging with a corresponding lateral extension of the outer retinal disruption on Fourier domain OCT. Thinning of the outer nuclear layer persisted in all patients with lesions >100 µm width, and in one patient this thinning worsened over the course of follow-up, as noted on the sublayer maps. This structural abnormality correlated with long-term functional deficits, persisting up to 14 months after the initial episode. Infrared reflectance highlights the lesion best, and abnormalities on near IR autofluorescence may be present. CONCLUSION: Acute macular neuroretinopathy acutely affects the outer nuclear and plexiform layers manifesting as OCT hyperreflectivity. The hallmark long-term changes are outer nuclear thinning on Fourier domain OCT and a fading dark lesion on IR reflectance imaging. These changes correspond to focal disruption of the outer segment/retinal pigment epithelium junction on OCT, and not the inner segment/outer segment junction, as previously reported. Optical coherence tomography and near IR autofluorescence abnormalities suggest previously unrecognized melanin and retinal pigment epithelium derangements in this condition.

Structural and functional implications of severe foveal dystopia in epiretinal membranes.

PURPOSE: The purpose of this study was to examine the functional and structural correlates of severe foveal dystopia in patients with epiretinal membranes. METHODS: For this retrospective study of 29 eyes with epiretinal membrane, we identified 7 eyes that had severe foveal dystopia (defined as fovea located >200 µm from its expected location) and followed the direction and rate of foveal movement pre- and postoperatively. RESULTS: Epiretinal membrane traction caused the fovea to move preoperatively at a rate of 275 µm/month from its anatomical location in 2 patients. The final preoperative foveal location was, on average, 1,217 ± 683 µm away from its expected location. Postoperatively, foveal movement toward its expected location was largest during the first month after surgery (mean = 547 ± 340 µm) and slowed down until the final follow-up position was achieved (mean = 301 ± 131 µm). Overall, the fovea moved a total of 848 ± 445 µm, allowing the fovea to correct only 32.8 ± 22.1% of the total displacement from its expected location. A univariate regression model confirmed a linear relationship between preoperative visual acuity and preoperative foveal distance from its expected anatomical location with an R of 0.759 (P = 0.0107). CONCLUSION: The extent of tractional foveal dystopia correlates with decreased visual acuity. Although all patients experienced functional and anatomical improvements with surgery, long-standing or severe foveal dystopia may be associated with permanent structural changes that limit functional outcome. Cases with extreme degrees of foveal dystopia may benefit from early intervention to prevent irreversible structural and functional changes.