Chapter 13 EYE

It is dependent on the ability of the eye to refract light rays and focus them on the retina.

The shape of the eye is one determinant in the refractive and focusing processes of vision.

It is the normal refrective condition of the eye in which light rays are brought into sharp focus on the retina.

• Nearsighted...It is generally inherited.
• Occurs when the eye is longer than normal
• Light focuses in front of the retina.

• It is farsightedness. an inherited condition
• -eye is shorter than normal
• -light rays focuses behind the retina

familial condition in which the refraction of the light is spread over a wide area rather than on a distinct point on the retina. in the normal eye, the cornea is round shape, whereas, in astigmatism cornea curves more in one direction than another.

it is an age related condition in which the lens of the eye loses the ability to accommodate. As a result, light is focused behind the retina and focus on near objects becomes difficult.

in the localized damaged areas.

unilateral blindness meaning you are blind with one eye

(When your blind from both end sides of your eye) bilateral heteronymous hemianopsia (loss of temporal visual fields)

vision diminishes in affected area.

Lesion occurs in uncrossed fibers of optic chiasm

Right optic or optic radiation lesion resulting in loss of right nasal and left temporal fields.

by six extraocular muscles and cranial nerve III, IV, VI.

by assesing the fields of gaze, corneal light reflex, and performing the cover test.

a condition in which the axes of the eyes can't be directed at the same object.

esotropia and exotropia

convergent in which the eye deviates inward

divergent in which the eye deviates outward

tonic pupil

Unilateral and sluggish pupillary response

Pupil exist bilaterally and are small, irregular and nonreactive to light.

it occurs with central nervous system disorders including tumor, syphilis and narcotic use.

unequal pupillary size, which may be normal finding or central nerous system disease

• it results in unilaterally dlated pupil.
• No reaction to light.
• Ptosis may be seen

it is a result of blockage of sympathetic nerve stimulation.

unilateral, small regular pupil that is nonreactive to light. Ptosis and anhidorosis of the same side accompany the pupillary signs.

a fixed and dilated pupils. it occurs with sympathetic nerve stimulation, glaucoma, central nervous damage or deep anesthesia.

a fixed and constricted pupils. it occurs with the use of narcotics, damage to the pons or a result of treatment for glaucoma.

it results in direct and consenual response to light directed in the normal eye and absence of response in either eye when light is directed in the blind eye.

the cornea appears cloudy and steamy