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Refraction and keratometry in 40 week old premature (corrected age) and term infants
M Snir1, R Friling, D Weinberger
1Pediatric Ophthalmology Unit, Schneider Children's Medical Center of Israel, 14 Kaplan Street, Petah Tiqva 49 202, Israel. moshesnir@hotmail.com
Insights
Premature infants at 40 weeks corrected age show mild hypermetropia and higher keratometry compared to term infants. Birth weight and gestational age did not impact these ocular parameters in preterm babies.
Area of Science:
- Ophthalmology
- Neonatology
- Pediatric Optometry
Background:
- Premature infants often experience visual development differences.
- Understanding ocular parameters in preterm infants is crucial for early intervention.
Purpose of the Study:
- Compare refraction and keratometry in premature vs. term infants at 40 weeks postconceptional age (PCA).
- Investigate the influence of birth weight (BW) and gestational age (GA) on ocular parameters in preterm infants.
Main Methods:
- Matched cohort study comparing 33 preterm and 33 term infants.
- Ophthalmic examinations at 40 weeks PCA included cycloplegic retinoscopy and keratometry.
- Analysis of refraction, astigmatism, and keratometric readings, correlated with BW and GA.
Main Results:
- Preterm infants had mild hypermetropia and higher keratometric values compared to term infants at 40 weeks PCA.
- Retinopathy of prematurity (ROP) decreased from 88% to 36% by 40 weeks PCA in preterm infants.
- Gestational age and birth weight did not significantly affect refractive or keratometric findings in preterm infants.
Conclusions:
- Infants with mild ROP at 40 weeks PCA exhibit mild hypermetropia and increased corneal curvature compared to term infants.
- Higher and steeper keratometric values in preterm infants may predispose them to myopia.
- Early awareness of potential visual dysfunction is essential for ophthalmologists and parents of premature infants.
Aim:
To compare refraction and keratometry readings between premature and term babies at 40 weeks' postconceptional age (PCA), and the possible effect of birth weight (BW) and gestational age (GA) on ocular parameters.
Methods:
33 preterm babies hospitalised in the neonatal unit between January and March 2002 were matched with 33 term babies born within the same period and hospitalised in the same unit. The preterm group underwent funduscopy at 4-5 weeks after delivery. Ophthalmic examination at 40 weeks' PCA included cycloplegic retinoscopy, funduscopy, and keratometric measurements. Mean and standard deviation of refraction, astigmatic power (plus cylinder), axis of astigmatism, and keratometric reading were calculated and compared between groups and correlated with BW and GA in the premature babies.
Results:
Retinopathy of prematurity (ROP) stage 1 or 2 was noted in 88% of the premature babies on the first funduscopy examination, but only in 36% by the corrected age of 40 weeks. Statistically significant between groups differences were found for cycloplegic refraction (p = 0.02 for both eyes) and keratometry (p = 0.001 for both eyes). GA and BW had no impact on the refractive and keratometric findings in the preterm babies.
Conclusions:
Babies with mild ROP at the corrected age of 40 weeks have mild hypermetropia compared to the moderate hypermetropia found in term babies (a difference of 50%), and they have higher and steeper keratometric values. The greater corneal curvature may contribute to the development of myopia. Ophthalmologists and parents need to be aware of the possibility of visual dysfunction already very early in life even in relatively older premature infants.
