The Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study

The Orinda Longitudinal Study of Myopia (OLSM) was started in 1989 to investigate normal eye growth and the development of myopia in over 1,200 school-aged children to date. Beginning in 1997, three parallel study phases are being conducted. Phase 1 investigates additional factors that may predict the onset of juvenile myopia (accommodative function, peripheral refractive error, intraocular pressure, and school achievement). Phase 2 compares and contrasts the optical ocular components and refractive error profiles of other ethnic groups with the predominantly Caucasian Orinda database. Phase 3 conducts DNA-based studies on the prevalent OLSM myopes and their families to use these phenotypically well-characterized children and a panel of candidate genes to look for evidence of genetic factors. In parallel with the candidate gene association, family material is used in an allele sharing approach to identify loci using highly variable, PCR-based markers.

In Phase 1 we continue to examine Orinda Union School District children in grades 1 through 8 (ages 6 through 14 years) annually. The measurement of accommodative response, accommodative lag, phoria, response AC/A ratio, peripheral refractive error, and intraocular pressure will be added to the existing protocol, and photokeratoscopy and two measures of tonic accommodation will be eliminated to minimize respondent burden. Parents of children in the study will be contacted for their permission to release school achievement data (Iowa Test of Basic Skills).

Phase 2 adds a major component by adding three clinical centers to assess the influence of ethnicity on normal ocular and refractive error development. Children in these three are examined annually with initial enrollment in all grades from 1 through 8 using the revised OLSM protocol as described above.

Increased prevalence of myopia among children of myopic parents, twin studies, segregation analysis, and our own preliminary analyses from the OLSM support a genetic etiologic component for myopia. In phase 3, we use the phenotypic characterization of children in the Orinda Longitudinal Study of Myopia to identify prevalent cases of myopia and their families. These well-defined phenotypic myopes and non-myopic siblings and their parents are being explored, seeking to develop a panel of candidate genes for myopia and to conduct an allele sharing analysis in these families

The Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study is a multi-center, observational investigation of ocular development and refractive error development in schoolchildren. It adds three clinical centers to the Orinda Longitudinal Study of Myopia (OLSM), begun in 1989, specifically to describe normal ocular growth in children ages 6 to 14 years, and to develop the ability to predict juvenile onset myopia before it is clinically evident. In addition to the more than 1,300 predominantly Caucasian children enrolled in the OLSM, three additional clinical sites enroll African-American, Hispanic, and Asian children. The children are examined annually for at least four years. Examinations include visual acuity, refraction by a variety of methods (cycloplegic autorefraction being the primary outcome measure), cover test at distance and near, accommodative response assessment with the autorefractor, response AC/A ratio measurement, videophakometry, peripheral refraction, and A-scan ultrasonography.