Changes in relative position of choroidal versus retinal vessels in preterm infants

Abstract

Purpose : Little is known about choroidal vascular development in preterm infants. We have observed a novel finding that the relative positions of choroidal and retinal vessels change over time in preterm infants (Figure). The purpose of this study is to describe and analyze the frequency of this finding, and to identify factors associated with this finding using quantitative analysis.

Methods : Consecutive eyes with wide-angle retinal images (RetCam; Natus, Pleasanton, CA) with quality sufficient to enable visualization of choroidal and retinal vessels were analyzed as part of a prospective retinopathy of prematurity (ROP) cohort study. Retinal images captured during routine ROP screening from two sessions 5 to 7 weeks apart were included in this study. For the quantitative analysis, the distance of a characteristic landmark of choroidal vessels (e.g. vascular branch point) between the two sessions were measured. Univariate and multivariate analyses were performed to identify factors associated with the amount of change in relative vascular position.

Results : A total of 37 eyes from 37 preterm infants with mean gestational age (GA) of 26.22 ± 1.49 weeks were analyzed. Changes in relative position of choroidal versus retinal vessels were detected in all 37 eyes. The mean time interval between the two sessions was 6.02 ± 0.61 weeks, and mean postmenstrual age (PMA) at the first session was 32.6 ± 1.43 weeks. The mean difference in choroidal vs. retinal vascular position between the two sessions was 0.55 ± 0.16 mm. Univariate analysis revealed that eyes with type 1 ROP (n=13) showed significantly less movement than eyes with non-type 1 or no ROP (0.46 ± 0.16 vs. 0.60 ± 0.14 mm, P=0.016). PMA at the first time point showed a negative correlation with the distance (R=-0.4832, P=0.0025). Multiple regression analysis revealed that type 1 ROP and PMA at the first time point were significantly associated with less movement of retinal compared to choroidal vessels (P=0.035 and 0.004, respectively).

Conclusions : Choroidal vessels expand outward with respect to retinal vessels in preterm infants, which may imply relatively faster peripheral growth of choroid vs. retinal vessels. Eyes with type 1 ROP showed less difference in growth, which may represent compromised development of choroidal vasculature in eyes with severe ROP. In addition, choroidal growth rate in preterm infants appears to slow over time after birth.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.