Evaluating contrast sensitivity in Asian Indian preterm infants with and without Retinopathy of Prematurity

Abstract

Purpose : Contrast sensitivity function gives a more comprehensive assessment of spatial processing capacity of the visual system than visual acuity. Assessment of contrast sensitivity(CS) in an infant may help better evaluate visual function.Retinopathy of prematurity(ROP) in preterm infants may influence contrast.We report a prospective, non-interventional, observational study to evaluate contrast sensitivity in Asian Indian preterm infants with and without ROP using the Stripe Cards of Contrast Sensitivity (SCCS) test, measured at the first ROP screening session and correlated with their final ROP outcome and visual acuity.

Methods : 170 preterm babies born ≤ 2000 grams at birth and /or ≤ 34 weeks of gestation undergoing ROP screening were recruited. CS was measured using SCCS cards at first screening visit and when ROP screening was terminated. The examiner placed each card along the infant’s line of sight, at a distance of 38 cms, while watching the infant’s eyes through the peephole (Figure 1). Retinal status was documented on wide-field digital imaging (RetCam Shuttle) at each visit and vision was recorded using Teller acuity cards.

Results : Of the 173 study infants, 134 (77.5%) did not have any stage of ROP, 34 (87%) had Type 2 ROP and 5 (13%) had Type 1 ROP. The mean CS at first visit of the no ROP, Type 1 and Type 2 groups was 0.36 ± 0.07, 0.65± 0.19 and 0.46 ± 0.09 respectively (p<0.001). CS had a significant correlation with birth weight (R²=-0.291, p=<0.001) and gestational age (R²=-0.444, p=<0.001).The CS at the first visit correlated with visual acuity measured at 3 months of corrected age in logMAR (R²=0.122, p=0.01).(Figure 2)

Conclusions : Our study demonstrates that CS testing is possible at the bedside in preterm infants. CS at the initial visit when no infant had any disease correlated with ROP status and visual acuity. This may help predict progression of disease and its final outcome.CS was also an independent predictive factor for the severity of ROP making it a useful tool in the assessment and management of ROP in preterm infants.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

FIGURE 1-The SCCS card is placed along the infant’s line of sight, at a distance of 38 cm, while watching the infant’s eyes through the peephole.

 

FIGURE 2-Scatter-plot showing correlation between contrast sensitivity and visual acuity.