AIM: To describe causes, characteristics and parental consanguineous marriage of low vision patients referred to our clinic for taking low vision aids in Turkey.

METHODS: We conducted a retrospective study of 236 low vision patients who visited to our clinics in Istanbul from 2009 to 2013. Age and sex distribution, cause of low vision, parental consanguineous marriage, type of prescribed low vision aids, and changes of the visions were reviewed. In this retrospective study, visual acuity was classified based on best-corrected visual acuity in the better eye according to the World Health Organization definition(blindness, visual acuity(VA)<20/400; severe visual impairment, VA<20/200-20/400; mild to moderate visual impairment, VA<20/60-20/200). The causes of blindness and low vision were determined using the 10th version of International Classification of Diseases based on the main cause in both eyes. Vision aids were prescribed based on visual acuity and patients' requirements. To describe data, we used mean±SD and frequency.

RESULTS: The study included 236 patients, 65% male, with a mean age of 38.5±24.2 years(range, 6 to 95year). In result, male were more than female. The age group between 15 and 30-year-old(35.6%)was the largest age group. Mild to moderate visual impairment, severe visual impairment and blindness were present in 122(51.6%), 84(35.6%)and 30(12.7%)of the patients, respectively. Choroid and retina diseases(62.7%)were main causes of low vision. Elderly low vision patients macular degeneration is becoming a leading cause of low vision(61.3%). The causes of visual impairment were retinal and choroidal diseases(62.7%), nystagmus(23.7%), optic nerve and optic tract diseases(11%), congenital cataract(0.8%), and glaucoma(1.7%). Eighty-eight(37.3%)patients Galilean type; 116(49.2%)patients keplerian type telescopic glasses recommended. Eighteen(7.6%)patients had no improvement in visual acuity with low vision aids(LVA). Forteen patients(5.9%)were approved the magnifier for near vision. In most patients, the use of LVA is improved both near and distance visual function. Parental consanguinity is present in 62(26.3%)patients, most commonly between the ages of 15-30 were significantly higher in the group(50%).

CONCLUSION: Diseases of the retina and choroid are the main cause over 14 years old groups, nistagmus is the most common cause under 15 years old group of visual impairment among patients referred to our clinic in Turkey. Parental consanquinity was significantly higher in macular dystrophy and retinitis pigmentosa groups. Of genetics in the etiology of these diseases are known to be effective. For this reason, parental consanguineous marriage is a big problem still in Turkey.