Myopia, or nearsightedness, is a refractive error of the eye. Light rays from a distant object are focused in front of the retina and those from a near object are focused in the retina; therefore distant objects are ... Myopia, or nearsightedness, is a refractive error of the eye. Light rays from a distant object are focused in front of the retina and those from a near object are focused in the retina; therefore distant objects are blurry and near objects are clear (summary by Kaiser et al., 2004). For a discussion of genetic heterogeneity of susceptibility to myopia, see 160700.
Yang et al. (2009) examined 3 sibs from a consanguineous Chinese family with extreme high myopia and excessive extension of the axial length. The parents and grandparents were unaffected. None of the affected sibs had night blindness or ... Yang et al. (2009) examined 3 sibs from a consanguineous Chinese family with extreme high myopia and excessive extension of the axial length. The parents and grandparents were unaffected. None of the affected sibs had night blindness or photophobia, and all had normal corneas, irides, and lenses. Funduscopic examination showed similar changes in the 3 sibs, including a tigroid fundus and a circular choroidal defect around the optic disc. Optical coherence tomography and Heidelberg retina tomography revealed normal optic discs and normal thickness of the retinal layers. Electroretinography in 2 of the patients showed mild reduced amplitude of cone response; all patients had normal color vision based on Ishihara plate screening. No systemic abnormalities were observed in the patients.