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

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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