Disorders of the eye. Astigmatism Myopia - nearsightedness Hyperopia - farsightedness Presbyopia Color blindness Cataracts Glaucoma Conjuctivitis

Astigmatism Distortion of vision due to abnormal curvature of the cornea or lens Lenses can correct astigmatism

Myopia (nearsightedness) Common among young people - eyeball grows too rapidly during maturation & light is focused in front of the retina Can be corrected with the use of concave lens

Hyperopia(farsightedness) Light is focused behind the retina – Eye may be too short Can be corrected with a convex lens

Presbyopia Declining ability to accommodate Bifocals People who never needed glasses before may need convex lenses for reading

Color Blindness X linked trait; most often affects males Inability to distinguish between certain colors

Cataracts Loss of transparency caused when the lens becomes cloudy More common in older people Can be treated with surgery

Glaucoma Increased pressure on the optic disk due to build up of aqueous humor This can be treated one of two ways – Surgery of the Iris – Drugs that constrict the pupil

Conjunctivitis May be caused by smoke, dust, chlorine, bacteria, and viruses Most common in children may be treated with antibiotics