Computer-assisted image analysis of temporal retinal vessel width and tortuosity in retinopathy of prematurity for the assessment of disease severity and treatment outcome

Abstract

Purpose: To quantify the severity of retinopathy of prematurity (ROP) through temporal retinal vessel diameter and tortuosity by the use semiautomated analysis and to evaluate the effects of laser treatment on retinal vessel measurements. Methods: A total of 176 RetCam digital fundus images from 63 infants diagnosed with ROP between January 2005 and December 2008 were retrospectively analyzed with Retinal Vessel Measurement V5.8 software. Patients were classified into 1 of 3 groups: stage 1 and 2 (Group 1), stage 3 not requiring treatment (Group 2), and stage 3 requiring treatment (Group 3). Diameter and tortuosity of the 4 major temporal retinal arteries and veins close to the optic disk were quantified. Tortuosity was measured as central (within 2 disk diameters from the center of the optic disk) and paracentral (from 2 to 4 disk diameters). For Group 3, measurements of vessels immediately before treatment and all follow-up post-treatment measurements of vessels were analyzed. Results: Differences in central and paracentral arteriolar tortuosity were pronounced. The average central arteriolar tortuosities were 1.12 ± 0.018 for Group 1, 1.13 ± 0.018 for Group 2, and 1.32 ± for Group 3; the paracentral arteriolar tortuosities were 1.11 ± 0.019 for Group 1, 1.12 ± 0.019 for Group 2, and 1.31 ± 0.02 for Group 3. In the post-treatment analysis of Group 3 patients, significant reductions in all vascular measurements were observed compared to pre-treatment, except for central and paracentral vein tortuosity. Conclusions: Computerized systems can be used to objectively assess differences in vascular parameters between ROP stages. Copyright © 2011 Published by Elsevier Inc. on behalf of American Association for Pediatric Ophthalmology and Strabismus.