UNIT 1: Anatomy & Physiology of The Eye

Question 1

What makes the eye like a Camera?

Answer 1

-Automatic focus from one inch to several miles away.
-3D images.
-Control the amount of light to the eye.
-Contrast awareness.
-Transmit a coded message to “computer”.

Question 2

What are the parts of the human seeing system?

Answer 2

-Two sets of lenses (gather and focus images)
-Two sensing devices (detect light, send signals)
-A brain (interpret signals)

Question 3

Marginal Blepharitis

Answer 3

-Lid margins have build up of bacteria
-Dandruff of eyelids
-Sore, red lids
-Use socially medicated soap to cure

Question 4

Cataracts (Senile)

Answer 4

-Most common
-The lens, due to age, becomes opaque and dense.
-There is no cure, only solution is cataract extraction.

Question 5

Causes and Symptoms of Cataracts (Senile)

Answer 5

-Increasingly blurred vision and distortion.
-Distance visio0n deteriorates, while near vision may improve due to increased lens convexity.

Question 6

Cataracts (Traumatic)

Answer 6

-Most commonly caused by a foreign body injury to the lens, or a blunt trauma to the eyeball.
-BB gun frequent cause.
-Other causes: Arrows, sticks, rocks, over exposure to x-rays & radio active waves.

Question 7

Cataracts (Traumatic) Continued…

Answer 7

-The lens becomes opaque quickly after injury due to entry of aqueous, and sometime vitreous humor into the lens capsule.
-The cataract may be removed at the same time the foreign body is removed.

Question 8

Cataract (Congenital)

Answer 8

-Often caused if the mother has had maternal rubella (Measles) in the first trimester of pregnancy.
-Parent notices that the child does not see well during first few months of life. The pupil may appear white.
-Should be removed ASAP to avoid amblyopia in both eyes.

Question 9

Types of cataract surgery (Intracapsular Extraction)

Answer 9

Removal of the lens in total, capsule and all, though a 140-160 degree limbal incision.

Question 10

Types of cataract surgery (Extracapsular)

Answer 10

A limbal incision is made once more, leaving the posterior capsule behind.

Question 11

Types of cataract surgery (Phacoemulsification)

Answer 11

Lens and capsule fragmented and sucked out by ultrasonic vibrations.

Question 12

Conjunctivitis (Signs and Symptoms)

Answer 12

-The most common eye disease in the western hemisphere.
-Redness
-Tearing
-Foreign body sensation
-Scratching, burning
-Sensation of fullness around the eyes
-Itching
-Photophobia

Question 13

Glaucoma

Answer 13

-IOP too high, causing too much pressure on the optic nerve.
-Up to 24mm of mercury is normal.
-Approximately 50K people in the USA are blind due to glaucoma.
-Incidence in people over 40 is 1.5%.
-Common in A.A people (15x that of Caucasians)

Question 14

Glaucoma Continued..

Answer 14

-Once detected, we can stop the progression with miotics, however, we cannot repair any damage done.
-The only symptom is impairment of vision, which is too late to correct.
-Hereditary and is checked with tonometry.

Question 15

Macular Degeneration

Answer 15

-Exact cause unknown
-Age related (ARMD)
-Race, Gender, Family History, Smoking

Question 16

Amblyopia

Answer 16

-Decrease VA of one eye in the absence of organic eye disease.
-Uncorrectable with glasses.
-It is reversible only within a limited time period.
-Most common cause is strabismus.

Question 17

Chalazion/Hordeolum

Answer 17

-Chalazion: Inside the lid
-Hordeolum: On the lid
-Sometimes called a stye
-May use a warm compress to treat
-If it persists, go to the doctor to have it cut out in the office, or simply drained.

Question 18

Floaters

Answer 18

-Tint deposits, pieces of blood vessel and blood cells.
-The small, oddly-shaped “Floaters” are old pieces of the blood vessel floating around the vitreous humor, which is normally transparent.