Lens and cataract

Question 1

How was the lens formed

Answer 1

from surface ectoderm that is placed in position by infolding

Question 2

Is the lens thicker anteriorly or posteriorly

Answer 2

anteriorly

Question 3

Tips of lens fibers meet and form short lines called

Answer 3

suture lines

Question 4

Highly compacted nuclear lens fibers

Answer 4

nuclear sclerosis

Question 5

How can you differentiate nuclear sclerosis from cataract

Answer 5

Nuclear sclerosis is transparent and can be seen through with an ophthalmoscope

Question 6

What percentage of the lens is water

Answer 6

65%

Question 7

Besides water, what is the other main component of the lens

Answer 7

Protein

Question 8

What is the lens completely dependent upon for nutrients

Answer 8

the aqueous

Question 9

Function of the lens

Answer 9

focus light rays on the retina to allow optimal image processing and vision

Question 10

How is focusing of light achieved

Answer 10

accommodation

Question 11

What stabilizes and holds the lens in the center of the eye

Answer 11

zonules

Question 12

Where do zonules attach to the ciliary processes

Answer 12

ciliary body

Question 13

an eye that lacks a lens

Answer 13

aphakic eye

Question 14

Too small of a lens

Answer 14

microphakic

Question 15

too round of a lens

Answer 15

spherophakic

Question 16

What types of proteins increase and decrease with a cataract

Answer 16

Insoluble increase

soluble decrease

Question 17

What must be done in order to examine the lens

Answer 17

pupil fully dilated

Question 18

What effect will a cataract have on PLR

Answer 18

none

Question 19

Congenital absence of normal tissue

Answer 19

Coloboma

Question 20

How does a coloboma of the leans appear

Answer 20

flattened region of the equator of the lens

Question 21

Earliest and smallest cataract you can see

Answer 21

incipient

Question 22

Cataract with more of the lens involved than incipient. can still see tapetal reflection

Answer 22

Immature

Question 23

Cataract that looks solid, opaque, white marble. No tapetal reflection or retinal detail can be seen

Answer 23

Mature

Question 24

With a mature cataract, are PLR’s normal

Answer 24

Yes

Question 25

Cataract where lens starts to shrink and reabsorb. Difficult to differentiate from mature

Answer 25

Hypermature

Question 26

Cataract where nucleus liquefies

Answer 26

Morgagnian

Question 27

Cataract present at birth, nuclear

Answer 27

Congenital

Question 28

Cataract that occurs in young dogs. Possibly hereditary

Answer 28

Juvenile

Question 29

Cataract in older dogs. not hereditary

Answer 29

Senile

Question 30

Most common cause of cataracts in dogs. usually bilateral. usually progress to complete vision loss

Answer 30

Genetic

Question 31

Abnormal glucose metabolisim in the lens that causes cataract

Answer 31

Diabetic cataract

Question 32

Rate limiting enzyme for sorbitol pathway

Answer 32

aldose reductase

Question 33

cataracts common in poodles, labs, irish setters

Answer 33

Secondary to PRA

Question 34

lens becomes malnourished and accumulates toxins causing cataracts

Answer 34

Secondary to uveitis

Question 35

Opacity confined to the lens capsule

Answer 35

Capsular cataract

Question 36

Most of the opacity involves cortex directly beneath lens capule

Answer 36

subcapsular cataract

Question 37

cataract between capsule and nucleus

Answer 37

cortical cataract

Question 38

Opacity primarily in the center of the lens. Frequently congenital and nonprogressive

Answer 38

Nuclear

Question 39

cataract where Most involvement in the area of the lens equator

Answer 39

Equatorial

Question 40

Focal, central opacity in the center of the visual axis

Answer 40

polar cataract

Question 41

What is a sign that cataract is actively being produced

Answer 41

when vacuoles are visible

Question 42

Lens induced uveitis

Answer 42

any cataract will cause inflammation

Question 43

leakage of lens proteins through the intact lens capsule

Answer 43

Phacolytic uveitis

Question 44

How should you treat all cataracts larger than incipient in size and for how long

Answer 44

topical anti-inflammatory | rest of life

Question 45

What drugs are generally safe for long term use

Answer 45

NSAIDS

Question 46

What can occur when lens-induced uveitis has not been treated and there is chronic inflammation

Answer 46

secondary glaucoma

Question 47

formation of fibrovascular membrane on the surface of the iris

Answer 47

Pre-iridal fibroVascular membrane

Question 48

Penetrating trauma to the lens capsule disrupts lends fibers, leading to a cataract

Answer 48

Phacoclastic uveitis

Question 49

What is performed prior to cataract surgery

Answer 49

electroretinogram or ocular ultrasound

Question 50

Treatment of choice for lens extration

Answer 50

phacemulsification

Question 51

Subluxation

Answer 51

lens is partially dislocated

Question 52

luxation

Answer 52

lens in completely dislocated

Question 53

are posterior luxations or anterior luxations prefered

Answer 53

Posterior (non-painful)

Question 54

Lens coming forward and being trapped in the anterior chamber

Answer 54

Primary anterior luxation

Question 55

Is primary anterior luxation unilateral or bilateral

Answer 55

bilateral

Question 56

Loss of zonules cause by other intraocular disease

Answer 56

secondary lens luxation

Question 57

What is the most common cause of lens luxation in cats and horses

Answer 57

Uveitis

Question 58

what are the best treatments for primary lens subluxation

Answer 58

lifelong topical miotic therapy | surgical removal of the lens