1. Field of the Invention
The present invention relates to a method for diagnosing myopia, and in particular relates to a method for diagnosing myopia and/or myopia related complications by determining SNP (single nucleotide polymorphism) genotype in the BICD1 gene. Further, the present invention relates to a method for screening a material for treating myopia and/or myopia related complications.
2. Description of the Related Art
Myopia, also called near- or short-sightedness, is a refractive defect of the eye in which collimated light produces image focus in front of the retina when accommodation is relaxed. Those with myopia see nearby objects clearly but distant objects appear blurred. With myopia, the eyeball is too long, or the cornea is too steep, so images are focused in the vitreous inside the eye rather than on the retina at the back of the eye.
Myopia is a common eye condition worldwide. The prevalence of the condition varies widely among populations, genders, and ages (Invest Ophthalmol Vis Sci 1997; 38:334-40; Optom Vis Sci 2001; 78:234-9; J Formos Med Assoc 2001; 100:68-91). In the USA, the prevalence of myopia was estimated to be approximately 25% between ages of 12 to 54 years (Arch Ophthalmol 1983; 101:405-7). In the Baltimore Eye Survey, myopia was less common in blacks (19.4%) compared with whites (28.1%) (Invest Ophthalmol Vis Sci 1997; 38:334-40). High myopia (defined as refractive dioptric power≦−5.0 D in this study) accounted for 27% to 33% of all myopic eyes, corresponding to a prevalence of 1.7% to 2% in the general population in the USA (Arch Ophthalmol 1983; 101:405-7). Taiwan is among the highest risk areas in the world for myopia. Using the definition of less than −6.0 D for high myopia, high myopia is much more common in Asia. The percentage of myopia in Taiwan is 18% among Taiwanese school boys and 24% among Taiwanese school girls (J Formos Med Assoc 2001; 100:684-91). The totals are even higher than the 13.1% reported among young men in Singapore (Optom Vis Sci 2001; 78:234-9). Furthermore, the prevalence of myopia is increasing in Taiwan based on two large nationwide surveys (participant number>10,000) conducted in 1995 and 2000.
High myopia is associated with potential blinding conditions such as retinal detachment, macular degeneration, and glaucoma. It has been estimated that 5.6% of blindness among school children in the USA is attributable to myopia. Substantial resources are required for optical correction of myopia such as spectacles, contact lenses, orthokeratology, photorefractive keratectomy and laser in situ keratomileusis (LASIK). However, these corrections do not prevent the ocular complications mentioned above. Furthermore, complications arising from the use of contact lenses (Curr Opin Ophthalmol 1998; 9:66-71), orthokeratology (Cornea 2003; 22:262-4) and surgical procedures (J Refract Surg 2003; 19:S247-9) also impose additional risks to myopes. In the USA, treatment of myopia costs an estimated $250 million per year (Arch Ophthalmol 1994; 112:1526-30).
While studies have found that several risks were attributed to environmental factors, twin studies have indicated a strong genetic influence on myopia with the estimates of heritability ranging from 58 to 90% (Invest Ophthalmol Vis Sci 2001; 42:1232-6; Genet Epidemiol 1988; 5:171-81; Hum Hered 1991; 41:151-6; Br J Ophthalmol 2001; 85:1470-6). Using family data, it has been reported that a family history was a significant risk factor for high myopia (Invest Ophthalmol Vis Sci 2004; 45:3446-52). Several studies also demonstrated a similar finding (Optom Vis Sci 1996; 73:279-82; JAMA 1994; 271:1323-7; Invest Ophthalmol Vis Sci 2002; 43:3633-40; Optom Vis Sci 1999; 76:387-92; Invest Ophthalmol Vis Sci 2004; 45:2873-8). However, while few papers reported identifying susceptible myopia genes, none of the studies have been replicated, thus making the identification highly questionable.
Accordingly, what is needed in the art, is a method for diagnosing, treating, preventing or ameliorating myopia and/or myopia related complications.