Retinal Vessel Width in Infants at Risk for Retinopathy of Prematurity Between 31 and 34 Weeks Post-Menstrual Age

Abstract

Purpose: : To compare early retinal vascular width of subjects that develop Type 1 retinopathy of prematurity (ROP) requiring treatment with controls with no ROP or ROP less than Type 1.

Methods: : Digital fundus imaging was performed using a Nidek NM200D non-contact camera between 31 and 34 weeks post-menstrual age (PMA). Fundus photographs were masked and assessed using ROPnet semi-automated software (Ruggeri et al, University of Padua) which traces retinal vessels and estimates width in arbitrary units (AU). Mean and standard deviation (SD) of vascular width were measured for the major superior and inferior retinal arteries and veins. Retinal vessels of eyes that developed Type 1 ROP requiring treatment were compared with controls. 56 right eyes from infants at risk for ROP (weight ≤1251g and gestational age <30 weeks) were included.

Results: : 11 infants developed Type 1 ROP requiring treatment. Average PMA at the time of fundus photography was 33 weeks for both treated and control eyes. Grade-regrade comparisons from 14 eyes showed no statistically significant differences in any vessel parameters. Confidence limits of the grade-regrade differences for each of four vessels were within 10 AU for width and 5.5 AU for SD of width. On average, the group of eyes that developed Type 1 ROP requiring treatment had significantly larger mean vessel width for arteries (mean ± SE: 79 ±3.4 AU vs 67 ± 1.3 AU, p =0.0002) and veins (103 ± 4.7 AU vs 86 ± 2.3 AU, p = .003), than control eyes. The standard deviation of width of the largest artery was significantly larger for treated eyes (8.57 ± 0.65 AU vs 6.13 ± 0.31 AU, p=0.0008), than control eyes.

Conclusions: : The analysis presented here, which complements an analysis using a different computer-assisted algorithm (VesselMap) in a subset of this sample (Rabinowitz et al, 2007), reinforces the observation that retinal vessel width measured at 31-34 weeks PMA may help identify high-risk infants who are more likely to require treatment.

Keywords: retinopathy of prematurity • imaging/image analysis: clinical • retinal development