Abstract
Purpose: :
High myopia is highly hereditary and a common cause of irreversible blindness. We designed a case control study to elucidate genetic and environmental risk factors for high myopia. In this first analysis, we investigated ocular morbidity.
Methods: :
Persons with high myopia (≤ -6 D, age ≥25 yrs) and emmetropia (-1.5 D; +1.5 D, age ≥25 yrs) were examined at a single research center. We investigated best-corrected visual acuity (VA), autorefraction, axial length, performed fundus photography, optical coherence photography and Heidelberg retinal tomography. Differences between cases and controls were analyzed by independent samples t-test and Mann-Whitney test.
Results: :
228 high myopes (mean age 47,0 years) and 100 emmetropic controls (mean age 48,4 years) have been enrolled so far. Mean spherical equivalent was -10.10 versus -0.02 D (P<0.0001); axial length was 27.02 versus 23.44 mm (P<0.0001). The prevalence of visual impairment (VA <0.3 and ≥0.05) in high myopes over age 40 years was 3.2% (10/307 eyes) versus 0.6% (1/154 eyes, P<0.0001) in controls; of blindness (VA <0.05) 3.6% (11/307 eyes) versus 1.3% (2/154 eyes, P<0.0001). Myopic macular changes were present in 16.3% of cases, 67.8% had optic disc changes, and 11.7% had degenerative changes in the peripheral retina. Cataract or pseudophakia was present in 22.8% of cases versus 11% of controls (P=0.021); history of glaucoma was present in 4.4% of cases versus 1% of controls (P=0.027); and history of retinal detachment was present in 4.8% of cases versus 0% of controls (P<0.0001).
Conclusions: :
High myopia carries a high risk of ocular complications which may lead to severe visual impairment. Patients and doctors should be made aware of the ocular morbidity of high myopia.
Keywords: myopia • clinical (human) or epidemiologic studies: outcomes/complications • retina