Post on 27-Dec-2015
OBJECTIVEOBJECTIVE
IDENTIFY TYPES OF CORRECTIVE LENSES USED TO CORRECT SIGHT
PROBLEMS[COS 5, SAT 10]
OBJECTIVEOBJECTIVE
IDENTIFY TYPES OF CORRECTIVE LENSES USED TO CORRECT SIGHT
PROBLEMS
CORRECTIVE CORRECTIVE LENSESLENSES
EYE GLASSESCONTACTS
CONVEX LENSESCONVEX LENSES
DEFINITION:
Convex Lenses are corrective lenses used to help those who are farsighted.
CONVEX LENSESCONVEX LENSES
Convex lenses are thicker in the middle than at the edges.
When light passes thorough a convex lens, the rays bend toward each other.
Glasses or contacts with convex lenses magnify the print, allowing these people to read more easily.
FARSIGHTEDNESS
FARSIGHTEDNESSFARSIGHTEDNESS
Farsightedness, is a focusing problem, which occurs when the cornea is not curved enough, or the eye is shorter than normal. The reduced length means the light rays focus behind the retina, producing a blurred image.
FARSIGHTEDNESFARSIGHTEDNESSS
CONCAVE CONCAVE LENSESLENSES
DEFINITION:Concave Lenses
are corrective lenses used to help those who are nearsighted.
CONCAVE CONCAVE LENSESLENSES
Concave lenses are thicker around the edges than in the middle.
When light passes through a concave lens, they bend away from each other.
These lenses bend outward just enough to make distant objects seem closer.
NEARSIGHTEDNESNEARSIGHTEDNES
SS In a nearsighted person the cornea is too
steep or the eye is too long and the focal point is in front of the retina resulting in blurred distance vision.
For a farsighted person the focus of the eye is behind the retina. People who are farsighted can have trouble seeing at distance.
Using Contact Lenses
Contact Lenses
Like eyeglasses, contact lenses change the path of light. But with contact lenses, concave lenses are used for
both nearsighted and farsighted people. Because contact lenses are so close to the eye, they don’t need to be thick to
bend the light enough to correct a person’s version.
OBJECTIVEOBJECTIVE
IDENTIFY TYPES OF CORRECTIVE LENSES USED TO CORRECT SIGHT
PROBLEMS
CORRECTIVE CORRECTIVE LENSESLENSES
EYE GLASSESCONTACTS
Convex and Concave Lenses