Chapter 14: Eyes
Describe the different Chambers of the Eye
Anterior chamber; behind the cornea but in front of the lens Posterior chamber; behind the iris and around the lens; contains watery aqueous humor that is produced by the ciliary body Vitreous body; soft gelatinous humor
Fixation
Cover one eye and see if the eye that is behind the card can quickly focus on the object in front of you
Distinguish between direct light reflects an consensual light reflex.
direct light reflex occurs in the eye that receives the light stimulus. The consensual reflex occurs in the other eye that uses the same nerve. Cranial nerve 2
Discuss the most common causes of decreased visual function and older adults
Cataract formation: Lens clouds, proteins clumping in the lens and it's hard for lite to get through. glaucoma: increase in ocular pressure; gradual loss of peripheral vision (more common in men than women) macular degeneration:
Functions of the ciliary body, pupil, and Iris.
Ciliary body; controls the thickness of the lens. Iris; function as diagram to change the amount of light allowed into the eye. Pupil; contracted and controlled by contractions of the iris.
Name the six sets of extraocular muscles and the cranial nerve the innervates each one
Cranial nerve three; superior oblique, superior rectus, inferior oblique, inferior rectus, Cranial nerves four; medial rectus. Cranial nerve six; lateral rectus
Accommodation
Eyes come closer together as a look at something that is close
What cranial nerves innervate the six muscles that control I movement
III, IV, VI.
Identify common age-related changes of the Eye
Pupil size decreases. Lens elasticity decreases. Decrease in accommodation. Prebiopia. The vitreous humor not recycle that's frequently
Define pupillary light reflex
Shining light in ones Eye will cause the other to constrict
Describe the lacrimal System
The lachrymal apparatus is continuously washing the eye. It irrigate and keeps the conjunctiva and Scalera clean. Tears wash across the eye and drain into the lachrymal puncta. That then drains into the nasal duct
Translate the normal visual acuity of 20/20
The number on top is the distance that you are away from the chart. The bottom number is the distance that a normal person with normal vision will stamp from the chart. A smaller number on top is better
A test for accommodation
The person focuses on a distant object and then shifts the gauge to a near object about 6 inches away. At near distance, you would expect the pupils to converge, and the axes of the eyes to construct
Describe the method of testing for presbyopia
test near vision with a hand held vision screener with various sizes of print. Hold the card in good light about 35cm from the eye.