Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

CLIN SCI 4 EX2 > Lens/Vitreous > Flashcards

Lens/Vitreous Flashcards

1
Q

What is the function of the lens capsule

A

barrier function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the function of the lens epithelium

A

multiply through life
becomes lens fiber cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

lens fiber cells

A

transparent due to orderly arrangement
protein antigenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What cells of the lens have antigenic proteins

A

lens fiber cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why does the lens fiber cells have antigenic proteins

A

embryonic origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are zonule fibers

A

fibers attached to the lens equator
attach to the cilia body
hold the lens in place

if these are not there then we have a lens luxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What maintains lens transparency

A

-absense of blood vessels
-lack of pigmentation
-orderly arrangement lens fiber cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Nutrition of the lens comes from the

A

aqueous humor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the function of the lens

A

-Refraction of light
-Accommodation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

age related changes to the lens

A

nuclear sclerosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

lens opacity

A

cataracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

lens displaced from normal location

A

lens luxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the secondary changes of lens disease

A

-corneal changes
-anterior uveitis
-glaucoma
-retinal detachment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

normal aging change
constant lens fiber production
new fibers outside on cortex, old pushed into center onto the nucleus thus pushing fluid out (dehydration)
7+ years old in dogs

A

nuclear sclerosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the signs of nuclear sclerosis

A

-Circle within pupil
-Can see tapetum with transillumination
-Rainbow effect that happens when lights shine through nuclear sclerosis

might need to dilate eye to see better

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What causes nuclear sclerosis

A

aging changes (7+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

T/F: nuclear sclerosis happens in all species

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How do you treat nuclear sclerosis

A

not indicated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

significant cause of blindness in dogs
opacity of lens
due to disruption of orderly arragement of lens fiber cells

A

Cataracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Cataract with <15% coverage of lens

A

Incipient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Cataract with 15-99% of coverage

A

Immature (incomplete)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Cataract with complete coverage

A

Mature (complete)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Cataract where the body is trying to reabsorb the cataract

A

Hypermature (reabsorbing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Characteristics of incipient cataract

A

<15% of lens
small dark spot on retroillumination
minimal impact on vision
no treatment needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Characteristics of immature cataracts
>15-99% of lens largest stage where vision is impacts Still tapetum reflection is present Ideal stage for cataract sx refer Start on topical anti-inflammatory meds
26
What is the ideal stage for cataract sx
Immature
27
What should you do for immature cataracts
Start on topical anti-inflammatory meds (Diclofenac) Refer- ideal stage for cataract sx
28
Characteristics of mature cataracts
complete lens opacity complete vision loss no tapetum reflection good time for sx (refer) should always be on topical anti-inflammatory meds (lifelong)
29
Characteristics of hypermature cataracts
complete unless reabsorbing sparkly lens capsule wrinking lens induced uveitis poorer sx success should be on topical inflammatory meds
30
What are the causes of cataracts in dogs
1) Inherited: many breeds (Boston Terriers) , non-symmetrical, variable progression 2) Diabetes mellitus: symmetrical, rapid progression, bilateral, refer early
31
Inherited cataracts or non-symmetrical or symmetrical
non-symmetrical - one eye first but uni or bilateral and variable progression
32
Diabetes mellitus caused cataracts
-Symmetrical, very rapid progression -dogs only (increased aldose reductase in their aqueous) -bilateral -refer early
33
Why do only dogs develop cataracts with diabetes mellitus
(increased aldose reductase in their aqueous)
34
What is the pathogenesis of diabetes mellitus causing glaucoma in dogs
1) hyperglycemia- glucose in aqueous humor 2) glucose diffuses across lens capsule 3) Hexokinase pathway to metabolized glucose in lens supersaturated 4) Alternative pathway with aldose reductase produced sorbitol 5) Sorbitol too big to escape lens 6) Osmotic water absorbing occurs in lens leading to cataract
35
What are the signs of lens induced uveitis
-Episcleral injection -Diffuse corneal edema -Flare (proteins in anterior chamber) -Miotic pupil -Dyscoria -Hypermature cataract
36
you should start all hereditary and diabetic cataract cases on
anti-inflammatory medication if fluorescein negative
37
What causes secondary cataract
anterior uveitis
38
What is the most common cause of cataracts in horses and cats *
secondary cataract from anterior uveitis
39
How might cataracts develop from trauma
1) blunt trauma leading to anterior uveitis leading to cataract 2) penetration leading to lens fibers deranged leading to catract
40
You should use topical anti-inflammatory for all cataracts that are ________________________
progressive/immature, mature and hypermature
41
What is theo nly option for cataract tx
surgery (refer early)
42
What is the surgery for cataracts
Phacoemulsification - used phaco-machine, ultrasound that will breakdown the cataract and aspirate it out of the lens capsule removes the cortex of the lens then places an intraocular lens (artificial) if possible can only be done if lens capsule is intact
43
you can only place an intraocular lens if
the cortex is intact
44
pseudophakic
a patient that has intraocular lens (IOL) after phacoemulsification sx
45
aphakia
patient that is missing their lens after phacoemulsifcation sx for cataracts artifical lens was unable to be placd because cortex was not intact
46
What holds the lens in place and is broken down in lens luxation
zonule fibers
47
partial breakdown of the zonule fibers
lens subluxation
48
complete breakdown of the zonule fibers
lens luxation
49
What breed commonly gets lens luxations ***
Terriers - be careful when terriers shake toys
50
causes of lens luxation
1) Primary- inherited: terriers, chihuahuas, chinese crested, border colies 2) Secondary - uveitis, glaucoma, trauma
51
Clinical signs of lens subluxation
-Shallow, deep or unequal anterior chambers (AC) -Anisocoria -Aphakic crescent * see equator of lens -Vitreous presentation in AC -Iridodenesis (iris is moving) -Phacodensis (lens is moving) -Ocular hypertension (glaucoma) -Anterior or posterior= lens in front of iris or behind it
52
iris that is moving, seen in lens luxation
iridodenesis
53
lens is moving seen in lens luxation
phacodenesis
54
lens that is infront of the iris
anterior lens luxation
55
lens is behind the iris
posterior lens luxation
56
What are the clinical signs of anterior lens luxation
blepharospasm (painful) Epiphora lens in anterior chamber indistinct pupillary border central corneal edema anterior uveitis glaucoma
57
How do you diagnose anterior lens luxation
1) narrow to absent anterior chamber - slit lamp exam 2) Increased intraocular pressure (stopping angle) 3) Direct PLR often absent 4) Indirect PLR is very important *if intact then you still have vision in the other affected eye
58
With anterior lens luxation, what you tell you you have intact vision
indirect PLR
59
How do you treat anterior lens luxation
Surgery is required to save vision -170 degree perilimbal clear corneal incision -Lens and lens capsule is removed resulting in aphakia (no lens) hyperopia after surgery (farsighted) Otherwise we need to remove the lens
60
What happens after lens and lens capsule is removed
hyperopia after surgery (farsighted)
61
How do you fix the hyperopia after lens removal surgery
Doggles- fixes post surgery vision deficits
62
What are the clinical signs of posterior lens luxation
-apparent aphakic crescent * -DEEP anterior chamber -Vitreous strands through pupil -Lens on floor of vitreous -Eye usually comfortbale
63
How do you treat posterior lens luxation
Monitor IOP Control uveitis Use miotics (Demecarium Bromide, Latanoprost) -monitor for uveitis +/- steroid
64
What Miotic medications are used for posterior luxation cases
1) Latanoprost- prostaglandin analogue * 2) Demecarium Bromide - cholinesterase inhibitor
65
prostaglandin analgoue that is a miotic, used for posterior lens luxation
Latanoprost
66
Cholesterase inhibitor that is a mitiotic, used for posterior lens luxation
Demecarium Bromide
67
How can trauma to lens occur
secondary to fights or foreigh body penetration
68
What are signs of trauma to lens
-Blepharospasm -Epiphora Episceral injection Fibrin in AC *** Corneal opacity Lens opacity Miotic pupil
69
How do you treat trauma to lens in dog
Topical steroids if no ulcer Topical NSAID if no ulcer, IOP normal Oral pred or NSAID Ecollar cage rest referral if possible
70
highly malignant neoplasia that is unique to domestic cats secondary to lens trauma
Feline traumatic sarcoma
71
What are signs of feline traumatic sarcoma
middle age-older history of penetrating trauma year prior Phthisis bulba (small eye due to chronic intraocular inflammation) or glaucoma
72
What causes feline traumatic sarcoma
historically lens trauma leading to malignant metaplasia
73
How do you treat feline traumatic sarcoma
remove the eye immediately
74
What are the 3 stages of development of the vitreous
1) Primary: hyaloid system 2) Secondary: definitive vitreous 3) Tertiary: lens zonules 75% volume of eye
75
aging change in some animals where small white deposits of calcium and/or phosphorus looks like eye is a snow globe
Asteroid hyalosis
76
persistence of hyaloid artery leading to vascularization of the lens +/- fibrosis embryonic remnant can rupture with trauma
Persistent hyperplastic primary vitreous (PHPV)
77
Two diseases seen with the vitreous
1) Asteroid hyalosis 2) Persistent hyperplastic primary vitreous (PHPV)
78

CLIN SCI 4 EX2 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions