Impaired vision and blindness are common. About 3.4 million people in the US are blind or visually impaired. Vision is usually measured by visual acuity charts, and normal vision is expressed as 20/20 ...

Eye color genetics is complex, with multiple genes from each parent determining a person's eye color. Scientists once believed a single gene controlled eye color, but research shows that more than 50 ...

Eye color can be changed temporarily with cosmetic options like colored contacts or makeup, and permanently through surgical procedures. Surgical eye color changes come with risks like infection, ...