First Author: S.Degli Esposti UK
Co Author(s): O. Comyn P.G. Hykin P.J. Patel 0 0 0 0 0 0 0 0 0
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To evaluate limits of agreement between automated retinal thickness measurements from “fast” and “dense” Heidelberg Spectralis spectral-domain optical coherence tomography (SD-OCT) scans in subjects affected with diabetic macular oedema (DMO).
Moorfields Eye Hospital NHS Foundation Trust, London, UK
Fifty eyes of 50 consecutive patients (32 male, 18 female) affected by DMO were included in the study. Patients underwent a visual acuity test and two consecutive scans in a single session using one Heidelberg Spectralis SD-OCT device operated by one or two experienced operators. A “fast macular volume” OCT scan, consisting of a 25-line horizontal raster scan covering 20°x20° centered on the fovea, was acquired followed by a “dense” one (49-line horizontal raster scan, covering the same area). Bland-Altman limits of agreement were calculated for automated retinal thickness measurements in the nine Early Treatment of Diabetic Retinopathy Study (ETDRS) subfields and center point thickness.
Mean age was 61.7 years (range 30 - 82 years). Mean visual acuity was 67 ETDRS letters (range 47 - 82 letters). Mean central macular thickness was the same with the two different scan setting (476 μm, range 305-820 and 288-812 for the “fast” and the “dense” scan respectively). Mean difference between the two scans in the central subfields was 0.2 μm (95% confidence interval -36.8 μm to 37.2 μm). In the other subfields it ranged from 0 μm to 4 μm. Mean difference in the center point thickness was -3.1 μm. Good limits of agreements were shown in every ETDRS subfield in Bland-Altman plots.
Retinal thickness measurements in subjects with DMO obtained using Spectralis SD-OCT through a “fast” scan or a “dense” scan show excellent limits of agreement. The results suggest that the “fast” scan may be used instead of the “dense” scan when rapid image acquisition is needed.