Incident Anisometropia Risk Factors Identified in Schoolchildren

Significant risk factors for incident anisometropia in schoolchildren include higher myopia at baseline, female sex, less time spent in after-school outdoor activities and performing near work at a distance of less than 30 cm, according to a 2-year longitudinal prospective study published in Ophthalmic and Physiological Optics.  

Researchers conducted a multicenter investigation including 7035 children (age, 8 years; 51.1% boys) who underwent biannual comprehensive eye examinations during a 2-year period. The team collected demographic information and parental history and determined lifestyle and near-work habits utilizing parent-administered questionnaires at the first and last visits. The study defined anisometropia as a 1 diopter (D) or more difference in the spherical equivalent (SE) refractive error between the 2 eyes. 

The 2-year cumulative anisometropia incidence was 7.6%, with an annual incidence of 3.9% and 3.7% in the first and second years, respectively.

Multivariable logistic regression analysis showed that baseline SE (odds ratio [OR], 0.87; 95% CI, 0.80-0.95) and female sex (OR, 1.24; 95% CI, 1.02-1.50) were significant risk factors for incident anisometropia. 

Controllable risk factors for increased anisometropia risk included participating less than 1 hour per day in after-school outdoor activities on weekdays (OR, 1.38; 95% CI, 1.08-1.76) and performing near work at a distance of less than 30 cm (OR, 1.33; 95% CI, 1.08-1.64) according to the report. 

Multiple linear regression analysis showed that the inter-eye difference in SE increased significantly in children performing near work at distances less than 30 cm (adjusted β=0.03; P =.02).

“These results support the hypothesis that certain lifestyle behaviors may exert asymmetric influences on the regulation of ocular growth and refractive status
between the two eyes,” according to the study authors.

Study limitations include potential recall bias, the use of various myopia control interventions, and the inclusion of students from schools in only 1 city.