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Nita Valikodath, N.Venkatesh Prajna, Lakshey Dudeja, Maria A Woodward; Variability in Corneal Ulcer Measurements. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4812.
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© ARVO (1962-2015); The Authors (2016-present)
Ophthalmologists rely on accurate measurements to diagnose and manage corneal ulcers. We performed a study to determine the variability between examiners when measuring corneal ulcer parameters including epithelial defect (ED), stromal infiltrate (SI), and hypopyon sizes.
Patients with corneal ulcers were recruited from a cornea clinic at Aravind Eye Hospital, Madurai, India. Three ophthalmologists and one mid-level ophthalmic provider measured the ED and SI height/width and hypopyon height. Height was the largest vertical measurement while width was the largest horizontal measurement. Wilcoxon signed rank tests were used to determine if the difference in measurements between graders pairs was significantly different than 0.5mm for ED and SI height/width and 0.25mm for hypopyon height. Intra-class correlation coefficients (ICC) were used to determine the reliability between graders.
36 patients were enrolled. For ED size, the absolute height difference between grader pairs ranged from 0-4.6 mm (range of means: 0.39-0.76 mm) and width ranged from 0-6.4 mm (range of means: 0.53-1.22 mm) (n=27 eyes). ED width was significantly different from 0.5 mm for 3 of the 12 grader pairs (Grader 1 vs 3, mean absolute difference ± standard deviation = 0.83 ± 0.77, p=0.04; Grader 1 vs 4, 1.22 ± 1.35, p=0.003, Grader 3 vs 4, 1.17 ± 1.27, p<0.001). For SI size, absolute height difference between grader pairs ranged from 0-3.2 mm (range in means: 0.38-0.67 mm) (n=33) and width ranged from 0-4.2 mm (range in means: 0.50-0.98 mm) (n=34) between pairs of graders. SI width was significantly different from 0.5 mm for 3 of the 12 grader pairs (Grader 1 vs 3, 0.95 ± 0.96, p=0.01; Grader 2 vs 3, 0.86 ± 0.73, p=0.002; Grader 3 vs 4, 0.98 ± 0.79, p<0.001). Absolute difference in hypopyon height ranged from 0-0.8mm (range in means: 0.14-0.26 mm) (n=14). This was not significantly different from 0.25 mm for any grader pairs (all p >0.05).ICC between all graders was 0.76 (95% confidence interval, CI=0.63, 0.87) for ED height and 0.71 (95% CI=0.55, 0.83) for ED width. ICC was 0.85 (95% CI=0.76, 0.91) for SI height and 0.77 (95% CI=0.66, 0.87) for SI width. ICC was 0.96 (95% CI=0.92, 0.99) for hypopyon size.
There was good to excellent reliability between the four graders but there was significant variability in some grader pairs. Graders were less reliable in measurements of width compared to height.
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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