PURPOSE Axial length has been shown to explain up to 50% of the total variance in refraction, with axial length and refraction having a major genetic component. However, no study has attempted to determine whether the correlation between axial length and refraction is explained by shared genetic or environmental factors. METHODS All twins from Victoria aged 18 years or older were invited to p...

Worldwide, and especially in Asia, myopia is a major vision-threatening disorder. From AD 1600 on, to prevent myopia, authors warned against near work without sufficient pauses. There was an abundance of theories about the causes of myopia, the most common one being the necessity of extra convergence on nearby work with thickened extraocular muscles and elevated intraocular pressure. Ocular ten...

PURPOSE The aim is to evaluate the association between high myopia and genetic variant in the BicC family RNA binding protein 1 (BICC1) as well as its association with Ras protein specific guanine nucleotide releasing factor 1 (RASGRF1) genes in a Chinese Han population with a case-control study. METHODS Five TagSNPs in BICC1 and RASGRF1 genes were selected and genotyped in 821 unrelated subj...

PURPOSE To evaluate possible seasonal variations in myopia progression and ocular elongation in school children. METHODS Seventy-one children who were enrolled in a clinical trial of bifocals were examined every 6 months for 30 months. Three 6-month intervals ("winters") included none of the summer vacation from school, and two intervals ("summers") included all of the summer vacation. Myopia...

PURPOSE Most studies have reported only minimal reductions in myopia progression with bifocal or progressive multifocal spectacles, although somewhat larger, although mostly still clinically insignificant, effects have been reported in children with nearpoint esophoria and/or accommodative dysfunctions. The CONTROL study was a 1-year, prospective, randomized, clinical trial of bifocal contact l...

Introduction The refraction of the eye is determined by four ocular components: corneal power, anterior chamber depth, lens power and vitreous chamber depth. From birth to adulthood the axial diameter of the human eye increases by approximately 7 mm. This change would result in significant refractive error (> 15 D) if compensatory changes in the other ocular components did not occur. However, f...

Axial eye growth rates in the chicken are controlled by local retinal image-processing circuits. These circuits quantify the loss of contrast for different spatial frequencies and promote axial eye growth rates in correlation with the amount of retinal image degradation ("deprivation myopia"). They also distinguish whether the plane of focus lies in front of or behind the retina. How the sign o...

PURPOSE We investigated changes in anisometropia and aniso-axial length with myopia progression in the Correction of Myopia Evaluation Trial (COMET) cohort. METHODS Of 469 myopic children, 6 to <12 years old, enrolled in COMET, 358 were followed for 13 years. Cycloplegic autorefraction and axial length (AL) in each eye were measured annually. The COMET eligibility required anisometropia (inte...

The myopic growth process has the potential to modify both the optical and neural performance of the eye. We provide three simple models, based on different types of retinal stretching, to predict changes in neural resolution resulting from axial length increases in myopia. These predictions are compared to visual acuity (VA) measures in 34 subjects with refractive errors ranging from plano to ...