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Neeley A Dukles, sruthi arepalli, Peter M Kaiser, Allison Watts, Jamie Reese, Sunil K Srivastava, Justis Ehlers; Normative Assessment of Outer Retinal Metrics Utilizing Ellipsoid Zone Mapping. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1887.
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© ARVO (1962-2015); The Authors (2016-present)
Ellipsoid zone (EZ) integrity has been linked to visual prognosis and function in various vitreoretinal disorders, but normative data is lacking for macular EZ metrics. The purpose of this study is to evaluate EZ and outer retinal metrics in eyes without macular disease across a wide age spectrum.
An IRB-approved retrospective image analysis study of 204 eyes of 204 subjects without macular pathology was performed. Line-by-line reviewed as performed by an expert reader to verify the absence of macular pathology. SD-OCT scans were analyzed using a novel automated EZ mapping tool with line-by-line manual verification of optimal segmentation. The output of the EZ mapping assessment including multiple quantitative metrics of macular EZ-retinal pigment epithelium (RPE) volume, central foveal EZ-RPE thickness, central foveal EZ-RPE area, en face percentage of EZ loss (EZ thickness = 0μm), and en face EZ attenuation (EZ thickness < 20 μm). Outer retinal parameters were also measured from the outer nuclear layer (ONL) to the RPE. Inclusion criteria included a Cirrus macular cube with signal strength of 7 of 10 or greater, sufficient for analysis. Exclusion criteria included a history of optic neuropathy, intraocular surgery besides for uncomplicated phacoemulsification, myopia greater than 6 diopters, macular pathology, and previous intraretinal or subretinal fluid. EZ parameters were assessed for correlation with age, and spherical equivalent.
Eyes ranging 10 to 84 years (mean 52.2) were analyzed. Clinical parameters were assessed for the overall group (n=202) and compared between 4 age quartiles; 1: 10-29 years (n=41), 2: 30-49 years (n=37), 3: 50-69 years (n=82), 4: 70-89 years (n=41). The mean central foveal EZ-RPE thickness was 49.94±6.13 microns in the overall group. The mean EZ-RPE volume was 1.19±0.11 mm3. Average map area of EZ attenuation was 0.47±1.23 mm2, and the average map area of EZ loss was 0.04±0.05 mm2. The mean central foveal ONL-RPE thickness was 126.13 ± 10.45 microns in the overall group. The mean ONL-RPE volume was 4.04± 0.30 mm3. Overall, the parameters between quartiles were similar.
This study provides important information on normative metrics for outer retinal parameters. Future research and clinical trials that focus on quantitative EZ integrity will be able to utilize this information for comparative assessment to normal. Minimal changes were noted with age.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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