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Alauddin Bhuiyan, Pallab Roy, Akter Hussain, Kim Lee, Ecosse Luc Lamoureux, Tien Yin Wong, Elsdon Storey, Yogesan Kanagasingam, Rao Kotagiri; Inter- and Intra-observer agreement of Newly Developed Software for Retinal Arteriolar Focal Narrowing Quantification . Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):5247.
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© ARVO (1962-2015); The Authors (2016-present)
To assess the accuracy and repeatability of novel computer based semi-automated software for quantifying the severity of retinal arteriolar focal narrowing (FN), a hypertensive retinopathy sign, from colour retinal photographs.
23 retinal photographs were randomly selected from the Envision Study, a population-based study of persons aged 70 years or over. Total 300 images were considered. The rest images were excluded for not having FN point or being poor quality. A novel computer assisted software was developed to quantify retinal FN by selecting vessel region semi-automatically where FN exists. The software then crops the FN region, calculates the vessel edges, computes the widths and finds the FN points by finding the width's sudden changes. The software provides quantified FN as continuous numerical values and the severity level as none, mild, moderate and severe. The accuracy of the FN computation method was tested against the manually measured FN severity level by expert grader through the Spearman rank correlation. Inter-grader reliability were assessed by measurements from two individual graders of the same eye and intra-session repeatability was assessed by grading the same image at two different times, using Intra-class Correlation Coefficients (ICC).
Accuracy measurements indicated a Spearman rank correlation (ρ) of 0.88 (p<0.001) between software measured FN values and expert graders’ ranking on FN severity. Between-graders and intra-session ICC values for FN were 0.94 (95% Confidence Interval [CI]: 0.85-0.97) and 0.93 (95% CI: 0.83-0.97) respectively, which indicates high repeatability of the proposed software for FN severity measurement.
A novel semi-automatic measurement system for retinal arteriolar focal narrowing quantification is demonstrated for accuracy and grading repeatability for the first time. A good agreement with standard grading and excellent reproducibility, indicating that quantitative assessment of retinal FN is possible.
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