china students glasses military balanceStudents in military uniforms balance bottles of water on their heads as they practice goose-stepping marching during a military training session at a college in Zhengzhou, Henan province September 17, 2014.REUTERS/Stringer
SPARKLY, spotted or Hello Kitty: every colour, theme, shape and size of frame is available at Eyeglass City in Beijing, a four-storey mall crammed only with spectacle shops.
Within half an hour a pair of prescription eyeglasses is ready. That is impressive, but then the number of Chinese wearing glasses is rising. Most new adoptees are children.
In 1970 fewer than a third of 16- to 18-year-olds were deemed to be short-sighted (meaning that distant objects are blurred). Now nearly four-fifths are, and even more in some urban areas. A fifth of these have “high” myopia, that is, anything beyond 16 centimetres (just over six inches) is unclear.
The fastest increase is among primary school children, over 40% of whom are short-sighted, double the rate in 2000. That compares with less than 10% of this age group in America or Germany.
The incidence of myopia is high across East Asia, afflicting 80-90% of urban 18-year-olds in Singapore, South Korea and Taiwan. The problem is social rather than genetic. A 2012 study of 15,000 children in the Beijing area found that poor sight was significantly associated with more time spent studying, reading or using electronic devices–along with less time spent outdoors.
These habits were more frequently found in higher-income families, says Guo Yin of Beijing Tongren Hospital, that is, those more likely to make their children study intensively. Across East Asia worsening eyesight has taken place alongside a rise in incomes and educational standards.
The biggest factor in short-sightedness is a lack of time spent outdoors. Exposure to daylight helps the retina to release a chemical that slows down an increase in the eye’s axial length, which is what most often causes myopia.
A combination of not being outdoors and doing lots of work focusing up close (like writing characters or reading) worsens the problem. But if a child has enough time in the open, they can study all they like and their eyesight should not suffer, says Ian Morgan of Australian National University.
Yet China and many other East Asian countries do not prize time outdoors. At the age of six, children in China and Australia have similar rates of myopia. Once they start school, Chinese children spend about an hour a day outside, compared with three or four hours for Australian ones.
Schoolchildren in China are often made to take a nap after lunch rather than play outside; they then go home to do far more homework than anywhere outside East Asia. The older children in China are, the more they stay indoors–and not because of the country’s notorious pollution.
Since poor sight is associated with higher incomes and more schooling, it is less prevalent in rural areas of China. In the countryside a third of primary-school students are myopic, compared with nearly half of urban children, according to the health ministry. But eyesight problems there are somewhat different. Stanford University’s Rural Education Action Programme found that one in six rural children with poor sight do not wear glasses–thanks to a combination of cost, poor eye care in schools and a mistaken belief that wearing glasses weakens eyes further.
When Stanford gave thousands of students free glasses, it found being able to see clearly had a higher impact on educational attainment than improving nutrition or the quality of teaching, says the programme’s co-director, Scott Rozelle. Another study reported that giving students free glasses improved test scores by the equivalent of nearly a year’s extra education.
Daylight and free glasses are both cheap remedies for a growing national problem. All that is required now is a bit of vision.

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Genetic Links in Myopia

 2015 Mar;36(1):1-7. doi: 10.3109/13816810.2013.812737. Epub 2013 Jul 8.

Evaluating the association between pathological myopia and SNPs in RASGRF1. ACTC1 and GJD2 genes at chromosome 15q14 and 15q25 in a Chinese population.

Abstract

BACKGROUND:

This study investigated the association of the 27 SNPs located in RASGRF1. GJD2, and ACTC1 genes with pathological myopia in a Chinese Han population.

METHODS:

Myopia patients were stratified according to whether they did (n = 274) or did not (n = 131) have myopic macular degeneration (MMD). The SNPbrowser software was used to identify specific SNPs for analysis and minimal allele frequency of >20%, and a pairwise r(2) < 0.85 were genotyped using MALDI-TOF mass spectrometry.

RESULTS:

Before controlling for false discovery rate, the frequency of the rs1867315 C/C genotype compared with healthy controls was lower in the myopia group (p = 0.006) and in myopia patients without macular degeneration (p = 0.019). The frequency of the rs670957A/A genotype was also lower in patients without MMD compared with controls (p = 0.045). For rs2070664, the frequency of the A allele was higher in the patients with MMD compared to those without MMD (p = 0.032). After controlling for a false discovery rate of 5%, there was no significant difference in genotype and allele frequencies between these groups.

CONCLUSION:

In this study, there was no association of the analyzed SNPs located in RASGRF1. GJD2, and ACTC1 with pathological myopia, suggesting that SNPs included in our study have no or a limited role in causing pathologic myopia in this Chinese Han population.

KEYWORDS:

Chinese; genotype; 
A genome wide association study in European-derived populations identified several single nucleotide polymorphisms (SNPs) strongly associated with ocular refraction at 15q25 and 15q14.16Hysi PGYoung TLMackey DAet alA genome-wide association study for myopia and refractive error identifies a susceptibility locus at 15q25. Nat Genet 2010;42:902905[CrossRef][PubMed][Web of Science ®],17Solouki AMVerhoeven VJvan Duijn CMet alA genome-wide association study identifies a susceptibility locus for refractive errors and myopia at 15q14. Nat Genet 2010;42:897901[CrossRef][PubMed][Web of Science ®] The associated SNPs in the region of 15q25 are near the RASGRF1 gene.16Hysi PGYoung TLMackey DAet alA genome-wide association study for myopia and refractive error identifies a susceptibility locus at 15q25. Nat Genet 2010;42:902905[CrossRef][PubMed][Web of Science ®] RASGRF1 encodes a guanine nucleotide exchange factor and is highly expressed in the human retina. RASGRF1 is regulated by muscarinic receptors and retinoic acid which may provide biological mechanisms for refractive control.15Wojciechowski RNature and nurture: the complex genetics of myopia and refractive error. Clin Genet 2011;79:301320[CrossRef][PubMed][Web of Science ®],16Hysi PGYoung TLMackey DAet alA genome-wide association study for myopia and refractive error identifies a susceptibility locus at 15q25. Nat Genet 2010;42:902905[CrossRef][PubMed][Web of Science ®] Two SNPs at chromosome 15q25, rs939658 and rs8027411, strongly associate with myopia in Dutch and British replication studies.16Hysi PGYoung TLMackey DAet alA genome-wide association study for myopia and refractive error identifies a susceptibility locus at 15q25. Nat Genet 2010;42:902905[CrossRef][PubMed][Web of Science ®] For the 15q14 region, the most significant association signal was for a polymorphism (rs634990) located in a putative regulatory region near the GJD2 and ACTC1 genes.15Wojciechowski RNature and nurture: the complex genetics of myopia and refractive error. Clin Genet 2011;79:301320[CrossRef][PubMed][Web of Science ®],17Solouki AMVerhoeven VJvan Duijn CMet alA genome-wide association study identifies a susceptibility locus for refractive errors and myopia at 15q14. Nat Genet 2010;42:897901[CrossRef][PubMed][Web of Science ®] GJD2 encodes a neuron-specific protein (CONNEXIN 36) that is present in the retinal photoreceptors, amacrine and bipolar cells.15Wojciechowski RNature and nurture: the complex genetics of myopia and refractive error. Clin Genet 2011;79:301320[CrossRef][PubMed][Web of Science ®] ACTC1 which encodes cardiac muscle alpha actin is also expressed in the retina.17Solouki AMVerhoeven VJvan Duijn CMet alA genome-wide association study identifies a susceptibility locus for refractive errors and myopia at 15q14. Nat Genet 2010;42:897901[CrossRef][PubMed][Web of Science ®] Currently, it is not clear how these three genes may influence the development of myopia. However, the involvement of 15q14 and 15q25, was recently confirmed by a large scale multi-cohort international study that included Caucasians and Asians.18Verhoeven VJ, Hysi PG, Wojciechowski R, et al.; Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Research Group, Evans DM, Timpson NJ, Verkerk AJ, et al.; Fuchs’ Genetics Multi-Center Study Group, Gorgels TG, Rudan I, Hayward C, et al. Genome-wide meta-analyses of multiancestry cohorts identify multiple new susceptibility loci for refractive error and myopia. Nat Genet 2013;45:314–318,19Verhoeven VJ, Hysi PG, Saw SM, et al. Large scale international replication and meta-analysis study confirms association of the 15q14 locus with myopia. The CREAM consortium. Hum Genet 2012;131:1467–80 A recent study in China also found alleles of rs634990 and rs524952 located on 15q14 showed evidence of allelic association with moderate to high myopia.20Jiao XWang PLi Set alAssociation of markers at chromosome 15q14 in Chinese patients with moderate to high myopia. Mol Vis 2012;18:26332646[PubMed][Web of Science ®] This same study did not find significant association of the SNPs analyzed at 15q25 with high myopia,20Jiao XWang PLi Set alAssociation of markers at chromosome 15q14 in Chinese patients with moderate to high myopia. Mol Vis 2012;18:26332646[PubMed][Web of Science ®] suggesting that other SNPs not yet investigated may influence the development of high myopia in Chinese populations.