Association of Season of Birth and Refractive Errors

Abstract

Objective: To date, many studies have been done to prove any association between refractive errors, season of birth and photoperiod in different regions. This study aims to find any association between these factors in Pakistani Population. Methods: Demographic data i.e. age, gender, educational level of all subjects was asked. After taking informed consent all patients were subjected to same preliminary tests i.e. visual acuity, family ocular history, pinhole, ophthalmoscopy, refraction by retinoscopy, Keratometry and axial length measurement using A-Scan. Results: Out of 318 subjects most were females (73.58%) and in range 21-25 years. BCVA of all subjects was 6/6 both for right and left eyes. Most of the subjects were born in summer and had myopic refraction (92.58%) while few were hypermetropic (7.55%) and most subjects have low refractive errors (0.75-2.99D). We found strong association between season of birth and refractive error (p-value:0.000) as well as K-readings and axial lengths as subjects born in summer were more myopic, had greateater corneal curvatures and increased axial lengths than those born in other seasons. However we did not find any association between hypermetropia (including ocular parameters associated with it) and season of birth. Conclusion: After adjusting for all other factors, people born in summer are more myopic with strong variation in axial length and corneal curvature. However hypermetropia does not show any significant difference. Key words: Season of Birth, Refractive Errors.