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.

Patients are examined at 4 clinical centers. The clinical centers have enrolled 3,493
patients as of April 28, 1999.

Children were eligible if they were enrolled in the first through eighth grades in
selected schools in Eutaw, Alabama; Houston, Texas; Orinda, California; or Irvine,
California in the 1997-98 academic year and in the first grade only in Eutaw, Houston, and
Irvine in the 1998-99 academic year.