Assessment of retinal structures in eyes with active and resolved neovascular age related macular degeneration

Abstract

Purpose: To evaluate changes in thickness of retinal layers in eyes with neovascular age-related macular degeneration (NAMD), which have shown resolution of retinal fluid after anti-VEGF therapy.

Methods: Spectralis optical coherence tomography (SD-OCT) images of 236 patients with established diagnosis of AMD managed at a tertiary care center over a 5-year period (2008-2013) were reviewed. Two SD-OCT images with choroidal neovascularization (CNV) lesion sizes of <2 disc diameters and have sufficient quality for proper segmentation were selected for each patient: image obtained at visit in which NAMD was confirmed and treatment was given and subsequent image of the same patient in which NAMD has resolved completely with no further treatment given. Two horizontal B-scans immediately above and below the CNV lesions with no obvious pathological changes on OCT were selected at each visit and average thickness values of full retinal thickness (FRT), retinal pigment epithelium (RPE), photoreceptor (PR), bipolar cell (BP), and combined ganglion cell/nerve fiber layers (GCL-NFL) were calculated using Heyex software v.5.2 along the central 5-mm of the B-scans in increments of 0.5 mm. Thickness values of individual retinal layers were compared to corresponding values of identical locations in eyes with no known ocular disease; standard deviations (SD) were calculated. Values were also compared between the two visits with active and inactive CNV.

Results: 30 scans from 16 eyes (16 patients) with NAMD met inclusion criteria and were segmented. Mean age was 81. Normative data was acquired from 20 subjects with mean age of 59. Mean number of anti-VEGF injections was 3.5; mean duration between initial treatment and CNV resolution with no treatment required was 11.2 months. Thickness values of individual retinal layers of the line scans adjacent to CNV lesions fell within two SDs compared to values from corresponding scans in normal eyes. Mean decrease in FRT between active and resolved CNV visits was 4.8um (p<0.05). Changes among individual layers were not statistically significant.

Conclusions: Descriptive analysis revealed that thickness values of individual retinal layers adjacent to CNV lesions are not different from corresponding values of normal retinae. FRT adjacent to CNV lesion demonstrated statistically significant decrease in thickness after resolution of fluid with anti-VEGF therapy.

Keywords: 503 drug toxicity/drug effects • 453 choroid: neovascularization • 412 age-related macular degeneration