Myopia epidemiologic studies: the concept of family risk scores

Abstract

Aim: Studies have demonstrated that there was a strong hereditary role in development of myopia. Family risk scores were developed to estimate familial risks more accurately. The reliability of the family history data was also assessed.

Materials and methods: A standardized questionnaire was developed to accurately quantify familial and other risk factors for the progression of myopia in Singapore children. 258 parents of myopic children were interviewed at a face-to-face clinic visit. Family history of myopia and severity of myopia in parents and siblings were documented. The age and sex of siblings were also noted. To assess test-retest reliability, the questionnaire was filled twice within a two week period by the parents of 30 children. 

Results: The number of children with no myopic parents was 37, one myopic parent was 97, and two myopic parents was 124 . The number of children with no parents with high myopia (myopia exceeding -6.0 Diopters) was 183, one parent with high myopia was 63, and two parents with high myopia was 12 . The proportion of myopic children with more than half of the first degree relatives being myopic was 68.7%. The family risk scores were negative for 48.91%, mildly positive for 41.85%, and definitely positive for 9.24% of the children. The reliability of the questionnaire for data for family history of myopia was very good with kappa statistics ranging from 0.75 to 1.00.

Conclusion: Family risk scores that quantify proportion of family members that are myopic would be a valuable tool for evaluating familial risks for myopia. The high proportion of myopic children with positive family history scores suggests that there may be genetic attributes in the development of myopia.