What is the cost of blindness?
D000368:Aged; D001766:Blindness / Q000191:economics* / Q000209:etiology; D017281:Cost of Illness; D003362:Cost-Benefit Analysis; D006801:Humans; D008268:Macular Degeneration / Q000150:complications / Q000191:economics*; D012943:Social Security / Q000191:economics