Detection of strabismus and amblyopia in 1.5- and 3-year-old children by a preschool vision-screening program in Japan.

All children at the age of 1.5 and 3 years in Japan undergo physical, mental, and developmental checkups including dental, eye, and hearing examinations. The vision-screening program consists of 3 steps : questionnaires and home visual acuity testing as the first step (only for 3-year-old children), visual acuity testing by nurses and inspection by medical officers at regional Health Centers as the second step, and detailed examinations by ophthalmologists as the third step. This study aims to reveal the prevalence of strabismus and amblyopia as obtained from data in the vision-screening program. The final diagnoses made by ophthalmologists and sent back to the Health Centers in Okayama City were reviewed to elucidate the prevalence of strabismus, amblyopia, refractive errors, and other diseases in 1.5- and 3-year-old children in Okayama City in 5 years from 2000 to 2004. Of approximately 6,500-6,900 total children, 83.7-86.8% at 1.5 years old and 77.8-81.9% at 3 years old were brought to the Health Centers. The rates of strabismus were 0.01-0.12% at 1.5 years old and 0.20-0.34% at 3 years old, while the rates of amblyopia were 0% at 1.5 years old and 0.13-0.18% at 3 years old. The higher rates of strabismus at 3 years old were attributed mainly to the increase of exotropia and intermittent exotropia. In conclusions, the prevalence of strabismus was different between 1.5- and 3-year-old children. The vision-screening program in Japan functions to detect strabismus and amblyopia.