Post on 27-Dec-2015
transcript
Eye Structure and Function
http://www.dailymotion.com/related/x4mv6d_zoom-into-concrete_tech/video/x4mqrz_zoom-into-a-human-eye_tech
Contains:
•rods:-receptors for night vision
•Cones: receptors for day vision and color
•Macula lutea
•Fovea centralis
Colorblindness• X linked recessive trait that
causes a problem with the color-sensing granules (pigments) in cones.
• If just one pigment is missing, you may have trouble telling the difference between red and green. This is the most common type of color blindness.
• If a different pigment is missing, you may have trouble seeing blue-yellow colors. People with blue-yellow color blindness usually have problems identifying reds and greens, too
• most severe form of color blindness is achromatopsia
• rare condition in which a person can’t see any color, so they see everything in shades of gray.
• lazy eye, nystagmus (small, jerky eye movements), severe light sensitivity, and extremely poor vision.
Astigmatism• optical defect in which
vision is blurred due to the inability of the optics of the eye to focus a point object into a sharp focused image on the retina.
• due to an irregular or toric curvature of the cornea or lens.
Glaucoma
Increased amount of pressure in the eye
damage to the optic nerve is due to increased pressure in the eye, also known as intraocular pressure (IOP).
Cataracts
A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging.By age 80, more than half of all Americans either have a cataract or have had cataract surgery.