How the eye works
How it works?
Eye problems:
Colour blindness - Colour blindness is when some people see colours differently and have a difficult time distinguishing certain colours.
Lazy eye - Lazy eye is a vision development disorder in which and eye fails to achieve normal visual acuity, even with glasses or contact lens.
Swollen eyelids - A swollen eyelid occurs when there is inflammation or excess fluid in the connective tissues surrounding the eye. Swollen eyes can be painful, and affect both the upper and lower eyelids.
Cataract - Cataract are cloudy areas that develop within the eye lens. Most cataracts are due to age-related changes in lens. Most of the time cataracts are small and don't effect your eye sight however if it gets larger or thicker you might need surgery.
Bibliography
http://images.medicinenet.com/images/image_collection/anatomy/eye-anatomy.jpg
http://www.aoa.org/patients-and-public/resources-for-teachers/how-your-eyes-work
http://www.nkcf.org/how-the-human-eye-works/
http://www.allaboutvision.com/conditions/colordeficiency.htm