Abstract
Purpose :
To investigate the role of duration of daylight hours during birth and the perinatal period in the development of refractive error.
Methods :
A total of 363,423 patients (177,110 male and 186,313 female) from age 18 to 98 in the United Kingdom from the Optical Express (Glasgow, UK) optometric database were analyzed. Only right eyes from each patient were included in the analysis. Myopia, defined by manifest spherical equivalence (MSE), was classified as low (-0.75 to -2.99 diopters [D]), moderate (-3.0 to -5.99 D), high (-6.0 D to -8.99) and very high (-9.00 or worse). Hyperopia was defined by MSE as low (0.75 to 1.99), medium (2.00 to 3.99), and high (4.00 or higher). Hours of sunlight on birth date were calculated and patients were divided into four different photoperiods based on hours of sun exposure during the perinatal period. Hours of sunlight on day of birth were compared between different subgroups and odds ratios (ORs) were calculated for each photoperiod for the development of refractive error using a logistic regression model.
Results :
Patients with moderate and high myopia had significantly higher hours of sunlight on birth date (p=0.001 and p=0.007, respectively), but those with low myopia had less hours of sun exposure (p=0.004). Patients with moderate hyperopia had significantly lower sunlight exposure (p=0.04), although this trend was not observed in the other hyperopia subgroups. The ORs for development of moderate myopia (1.03; p=0.01) and high myopia (1.04; p=0.04) were significant when comparing the shortest versus the longest photoperiods, although there was a lower prevalence of mild myopia with longer photoperiods (0.97; p=0.002). There was no significant association between the development of hyperopia and photoperiod in any subgroup.
Conclusions :
The development of moderate and high myopia in this population is associated with longer hours of sunlight exposure on day of birth and longer photoperiod during the perinatal period. Overall, this effect is small with only a 3-4% increased likelihood of developing moderate to high myopia during the longest photoperiod. There does not appear to be a strong relationship between development of hyperopia and shorter photoperiods in this population.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.