Abstract
Purpose :
Visual decline is a common occurrence in Stargardt disease secondary to macular atrophy with associated ellipsoid zone (EZ) loss. Reliable and objective measurement of the EZ is difficult with conventional methods. This study utilizes a novel EZ mapping analysis tool for en face visualization and volumetric EZ-retinal pigment epithelium (RPE) assessment in eyes diagnosed with Stargardt disease. The purpose of the study is to quantitatively characterize the EZ status in Stargardt disease and correlate the findings with clinical characteristics.
Methods :
This is an IRB-approved retrospective case series examining the OCT features of Stargardt disease. Macular cube scan data was exported for analysis. A novel EZ mapping tool was utilized to analyze volumetric measurements and en face characterization of relative EZ volume and atrophy. En face characterization included the percentage of macular scan area with total atrophy (EZ-RPE thickness = 0 microns) and percentage of macular scan area with EZ attenuation (EZ-RPE thickness < 20 microns). Clinical characteristics were correlated with EZ mapping features. EZ mapping values were compared to a normal cohort.
Results :
Thirty-two eyes were included in the study with a diagnosis of Stargardt disease. Clinical features included 20 eyes with macular flecks and 17 eyes with clinical macular atrophy. Mean EZ volume in Stargardt patients was 1.0 +/- 0.33 mm3. In normal eyes, the EZ volume was 1.27 +/- .09 mm3. Mean percentage of macular EZ attenuation area was 42% in Stargardt patients compared to < 1% in normal eyes. Similarly, mean percentage of macular EZ atrophy was 22% compared to < 1% in normal eyes. EZ maps demonstrated variable levels of atrophy [e.g., moderate (Figure 1), severe (Figure 2)]. EZ volume was directly correlated with visual acuity. Conversely, the percentage of EZ attenuation and EZ atrophy were negatively correlated with visual acuity.
Conclusions :
EZ mapping provided objective quantitative assessment of outer retinal integrity in Stargardt disease. Multiple EZ mapping parameters were correlated with visual acuity. Utilizing EZ mapping may provide a unique opportunity for longitudinal assessment in Stargardt disease and detect early features of macular atrophy.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.