Purpose
To investigate the relationship between microperimetry(MP) and tomographic metrics from automated segmentation of spectral-domain optical coherence tomography (SD-OCT).
Methods
Study sample: The overall study recruited 105 patients (53 males, 52 females) with unilateral advanced AMD from 3 Centres (Milan, Coimbra, Belfast) aged 52-93 years. Study Eye=Fellow eye without advanced disease. Best corrected distance acuity (BCVA) and near acuity (NVA), reading speed adjusted for print size (reading index; RI), low-luminance acuity were measured. Participants were assessed every six months, with a maximum follow-up of two years. High density macular raster scans on the Heidelberg HRA-OCT were obtained. Initially 35 study eyes from the Belfast centre were evaluated to assess structure function relationships. Of these 31 eyes had SD-OCT scans of sufficient quality for automated segmentation of the retina, ellipsoid zone, retinal pigment epithelium/drusen complex and choroid. OCT volumetrics were obtained in the ETDRS grid region using 3D-OCTOR software. Presence or absence of reticular drusen was assessed by trained graders. Registration between the microperimetry image and the OCTOR software enabled layer thickness at each MP loci to be calculated. Univariate analyses were employed to examine relationships between function and volumetrics, and the change in layer thickness and volume during follow-up.
Results
There was no significant change in volume of any of the layers between 6 monthly visits however retinal volume was significantly reduced between visit 1 to visit 5 (p=0.04). There was no significant difference in layer thickness or volume between those with reticular drusen and those without at baseline. There were significant decreases in retinal sensitivity and corresponding layer thicknesses over time. Significant correlations between localized retinal sensitivity and localised layer thickness were noted for the retina(r=0.28, p<0.001), ellipsoid zone (r=0.24, p<0.001), choroid (r=0.24, p<0.001) but not for the RPE/drusen layer (r=0.27, p<0.001).
Conclusions
Longitudinal analyses of the OCT automated segmentation shows that change in thickness of individual retinal layers is detectable throughout follow-up. Microperimetry deficits appear to correspond to OCT morphological features.
Keywords: 550 imaging/image analysis: clinical •
758 visual fields •
412 age-related macular degeneration