Abstract
Purpose::
To characterize age-, gender-, and ethnicity-related differences in axial length (AL) in African-American and Hispanic children 30 to 72 months of age.
Methods::
The Multi-Ethnic Pediatric Eye Disease Study (MEPEDS) is a population-based study of eye disease in children aged 6-72 months. Participants 30-72 months old undergo AL testing with the Zeiss IOLMaster as part of their clinical examination. A minimum of two measurements is obtained for each eye and the mean AL is recorded. Right and left eye correlation was determined using the Pearson correlation coefficient. Differences in AL between groups of age, gender, and ethnicity were examined using the two-sample t-test and the ANOVA procedure. AL values adjusted for age, gender, and ethnicity were evaluated using the general linear model.
Results::
AL measurements in both eyes were obtained from 3065 children (53% Hispanic and 47% African American; 49% males and 51% females) aged 30-72 months. There were 460, 831, 922, and 852 children in age groups of 30-36, 37-48, 49-60, and 61-72 months, respectively. There was no significant difference in AL between right and left eyes (R=0.97, p<0.0001), hence analysis was performed using right eye data only. The mean ± SD AL measurements increased with age: 30-36 months (21.63 ± 0.70mm), 37-48 months (21.85 ± 0.74 mm), 49-60 months (22.11 ± 0.73 mm), and 61-72 months (22.35 ± 0.78 mm). AL differed significantly by gender (males, 22.28 ± 0.76 mm; females, 21.80 ± 0.74 mm; p<0.001) and ethnicity (Hispanic, 22.07 ± 0.77 mm; African-Americans, 22.00 ± 0.80 mm; p=0.03). AL also differed significant between all groups (p<0.0001, one-way ANOVA). Male gender was associated with a 0.48 mm increase in AL (p<0.0001, adjusting for age and ethnicity). Also, AL increased by 0.27 mm for every 12 month increase in age (p<0.0001, adjusting for gender and ethnicity).
Conclusions::
Our data show that AL increases steadily with age from 30-72 months. Gender- and ethnicity-related differences in AL deserve further exploration to determine the underlying mechanisms and the clinical significance of differing AL within these groups.
Keywords: clinical (human) or epidemiologic studies: prevalence/incidence • visual development: infancy and childhood • anatomy