Purpose:
To compare central choroidal thickness in patients with early age-related macular degeneration (AMD) and reticular pseudodrusen (RPD) with controls using spectral domain optical coherence tomography (OCT).
Methods:
Retrospective review of patients evaluated at Doheny Eye Institute with Cirrus® high-definition OCT (HD-OCT, Carl Zeiss Meditec Inc, Dublin, CA USA) from June 2008 to July 2011. Choroidal thickness measurements were manually measured below the central macular HD-OCT. Cases with poor signal penetration through the entire choroid were excluded. The choriocapillaris was qualitatively assessed on HD-OCT by identifying the presence of a thin band with alternating hyper- and hypo-relective elements located immediately below the retina pigment epithelium.
Results:
In 58 patients, 38 (66%) were female. Eleven (19%) had early AMD (mean age 77) , and 33 (57%) had RPD (mean age 83) and 14 (24%) had epiretinal membranes and served as controls (mean age 61). Of the RPD patients, 23 eyes had early AMD changes and 10 eyes had choroidal neovascularization or geographic atrophy. One eye from each patient was included in the study. Choroidal thickness in the early AMD group was 207.0 microns (SD +/- 42.5), 163.4 microns (SD +/- 68.5) in RPD patients with mild AMD changes, 179.0 (SD +/- 99.4) in RPD patients with advanced AMD changes and 228.6 microns in the control group (SD +/- 58.4). Without controlling for age or gender, choroidal thickness was significantly lower in the reticular group as compared to controls (p-value 0.04). When controlling for age and gender these comparisons were not statistically significant. No eyes in the RPD had visible choriocapillaris on HD-OCT compared to 6/11 (55%) with early AMD, and 13/14 of controls (p-value <0.001, Fisher’s exact test).
Conclusions:
Decreased choroidal thickness (p=0.04) was only significant when not controlling for age in the RPD population. The visibility of choriocapillaris (p<0.001) on HD-OCT was decreased in RPD eyes when compared to controls or early AMD, suggesting that complex structural choroidal changes play a role in the pathogenesis of this disease. Further OCT data analysis is underway.
Keywords: retina • age-related macular degeneration • imaging/image analysis: clinical