Refractive Status at Birth: Its Relation to Newborn Physical Parameters at Birth and Gestational Age

Abstract

BackgroundRefractive status at birth is related to gestational age. Preterm babies have myopia which decreases as gestational age increases and term babies are known to be hypermetropic. This study looked at the correlation of refractive status with birth weight in term and preterm babies, and with physical indicators of intra-uterine growth such as the head circumference and length of the baby at birth.MethodsAll babies delivered at St. Stephens Hospital and admitted in the nursery were eligible for the study. Refraction was performed within the first week of life. 0.8% tropicamide with 0.5% phenylephrine was used to achieve cycloplegia and paralysis of accommodation. 599 newborn babies participated in the study. Data pertaining to the right eye is utilized for all the analyses except that for anisometropia where the two eyes were compared. Growth parameters were measured soon after birth. Simple linear regression analysis was performed to see the association of refractive status, (mean spherical equivalent (MSE), astigmatism and anisometropia) with each of the study variables, namely gestation, length, weight and head circumference. Subsequently, multiple linear regression was carried out to identify the independent predictors for each of the outcome parameters.ResultsSimple linear regression showed a significant relation between all 4 study variables and refractive error but in multiple regression only gestational age and weight were related to refractive error. The partial correlation of weight with MSE adjusted for gestation was 0.28 and that of gestation with MSE adjusted for weight was 0.10. Birth weight had a higher correlation to MSE than gestational age.ConclusionThis is the first study to look at refractive error against all these growth parameters, in preterm and term babies at birth. It would appear from this study that birth weight rather than gestation should be used as criteria for screening for refractive error, especially in developing countries where the incidence of intrauterine malnutrition is higher.

The relationship between anisometropia and amblyopia

“…Weale (2002) described the pattern as being ‘u’-shaped. Prevalence is high in the first few weeks of postnatal life (Zonis and Miller, 1974; Fulton et al, 1980; Varghese et al, 2009), but then decreases in early childhood (e.g. Atkinson et al, 1996), only to increase again in the teenage years as myopia emerges (e.g., Parssinen, 1990; Laird, 1991; Lin et al, 1999).…”

“…At or soon after birth, anisometropia prevalence has been reported to be 17.3% (n=300, >1D difference between vertical or horizontal meridia, Zonis and Miller, 1974) to 30% (n= 256, >1D difference in SE, Varghese et al, 2009). Larger scale, more population-based studies have been conducted on children from the age of 6 months (e.g., Dirani et al, 2010; Borchert et al, 2010) and, if the high anisometropia prevalence figures in the perinatal period generalise to a larger population, prevalence appears to drop considerably by the age of one year.…”

“…To summarise, the association between age and anisometropia prevalence has been described as a u-shaped function (Weale, 2002) although there is uncertainty about the early limb of the function in peri-natal humans; while very high prevalence of anisometropia has been reported at or shortly after birth (Zonis and Miller, 1974; Varghese et al, 2009), evidence to support this is somewhat limited (small participant numbers). At older ages, prevalence is low and stable from the age of one to the pre-teenage years before showing an increase linked to the onset of myopia.…”

Ophthalmological findings in relation to auxological data in moderate‐to‐late preterm preschool children

“…Previously, a relationship between birthweight (BW) and refraction at birth in both term and premature infants has been reported, weight being the better predictor than gestational age (GA) (Varghese et al. ). Furthermore, a study from New Zealand showed an increased risk of strabismus and subnormal visual maturation in moderate prematurity and/or low BW compared with normal BW at 6 years of age (Robaei et al.…”

“…Evidence is currently emerging that even near-term birth predisposes those children to a higher risk of mortality and morbidity than term infants (Engle et al 2007). To date, very few studies have focused on the ophthalmological aspects of this particular subset of children (Robaei et al 2006;Nilsson et al 2011). Previously, a relationship between birthweight (BW) and refraction at birth in both term and premature infants has been reported, weight being the better predictor than gestational age (GA) (Varghese et al 2009). Furthermore, a study from New Zealand showed an increased risk of strabismus and subnormal visual maturation in moderate prematurity and/or low BW compared with normal BW at 6 years of age (Robaei et al 2006).…”