Molecular biology of myopia§

Abstract

Experiments in animal models of myopia have emphasised the importance of visual input in emmetropisation but it is also evident that the development of human myopia is influenced to some degree by genetic factors. Molecular genetic approaches can help to identify both the genes involved in the control of ocular development and the potential targets for pharmacological intervention. This review covers a variety of techniques that are being used to study the molecular biology of myopia. In the first part, we describe techniques used to analyse visually induced changes in gene expression: Northern Blot, polymerase chain reaction (PCR) and real-time PCR to obtain semi-quantitative and quantitative measures of changes in transcription level of a known gene, differential display reverse transcription PCR (DD-RT-PCR) to search for new genes that are controlled by visual input, rapid amplification of 5' cDNA (5'-RACE) to extend the 5' end of sequences that are regulated by visual input, in situ hybridisation to localise the expression of a given gene in a tissue and oligonucleotide microarray assays to simultaneously test visually induced changes in thousands of transcripts in single experiments. In the second part, we describe techniques that are used to localise regions in the genome that contain genes that are involved in the control of eye growth and refractive errors in mice and humans. These include quantitative trait loci (QTL) mapping, exploiting experimental test crosses of mice and transmission disequilibrium tests (TDT) in humans to find chromosomal intervals that harbour genes involved in myopia development. We review several successful applications of this battery of techniques in myopia research.

Overcorrecting minus lens therapy in patients with intermittent exotropia: Should it be the first therapeutic choice?

“…It has been concerned that accommodative effort required with minus lenses may induce myopia or enhance myopic progression [14]. Schaeffel et al's studies showed that the eyes made functionally hyperopic with negative spectacle lenses became myopic in chicks [25][26][27]. On the other hand, there are controversial assessments in the literature about this issue.…”

“…Parssinen and Lyyra postulated that constant saccadic eye movements during reading, rather than accommodation and/or convergence, might induce myopic progression causing repeated pressure and stretch pulses on the eye [28]. The development of human myopia is also influenced to some degree by genetic factors [27]. Schaeffel et al [25] showed that accommodation is not necessary for growth that reduces refractive errors during development, and may not be necessary for the normal control of eye growth, at least in chicks.…”

Myopia: precedents for research in the twenty‐first century

“…Much has followed since 14−20 and the purpose of this review is to provide a synopsis of prospects for myopia research in the twenty‐first century. Precedents set by current and previous literature have generated compelling research questions.…”

High Myopia Is Not Associated with the SNPs in theTGIF, Lumican,TGFB1, andHGFGenes

“…5,6 Several lines of evidence have demonstrated that genetic factors play an important role in the development of high myopia. 1,[7][8][9] High myopia may be inherited as an autosomal dominant, autosomal recessive, or X-linked recessive trait. 8,10 Linkage studies have mapped at least eight loci (MYP1, MYP2, MYP3, MYP4, MYP5, MYP11, MYP12, and MYP13) responsible for high myopia with Mendelian inheritance, but none of the responsible genes has been identified.…”