Session Title: Free Paper Session 15: Mixed Session
Session Date/Time: Friday 08/09/2017 | 16:30-18:00
Paper Time: 16:54
Venue: Room 117
First Author: : A.Daruich SWITZERLAND
Co Author(s): : A. Matet L. Zografos
Accurate and reproducible measures of the foveal avascular zone (FAZ) dimensions on optical coherence tomography angiography (OCT-A) images of the superficial capillary network have been demonstrated in healthy eyes. However, reliability of measurement in patients with severe alterations of the FAZ, as in radiation maculopathy, has not been yet addressed. The aim of this study is to measure FAZ dimensions in eyes with radiation maculopathy using OCT-A, and to calculate interobserver variability and agreement between semi-automated and manual measurement methods.
Reliability analysis in a tertiary referral centre
Forty eyes diagnosed with radiation maculopathy after proton-beam therapy for uveal melanoma underwent OCT-A on the Angiovue RTx 100 device. Two masked observers (observer1, retinal photographer and observer2, retina specialist) performed measurements of FAZ area at the level of the superficial network on 33-mm OCT-A images using ImageJ. Intraclass correlation coefficients (ICC) were calculated to assess agreement between observers and between each observer and the semi-automated method (SAM) from the built-in Angiovue Analytics software. Based on the lower end of the 95%-confidence interval (95CI) of the ICC, values indicated poor (<0.5), moderate (0.5-0.75), good (0.75-0.9), or excellent reliability (>0.9), respectively.
The measured FAZ area was 0.608±0.633, 0.599±0.611 and 0.595±0.600 mm2 for observer1, observer2 and SAM, respectively. The agreement was excellent for FAZ measurements between observers 1 and 2 (ICC=0.997; 95%CI= 0.995-0.999). Agreement between each observer and the SAM was poor (observer1-SAM: ICC=0.530; 95%CI= 0.256-0.735 and observer2-SAM: ICC=0.560; 95%CI= 0.287-0.750).
Manual measurement of FAZ area using OCT-A is a reliable method. Assessing FAZ by a semi-automated method may be subject to greater variability.