Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

new > Lens disease > Flashcards

Lens disease Flashcards

1
Q

What embryologically occurs to cause aphakia?

A

failure of contact of optic vesicle with surface ectoderm = lens placode doesn’t form

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

How common is aphakia?

A

extremely rare

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

If you see a microphakic lens, what other lens change is commonly present?

A

Spherophakia

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

Other than congenital disorder, what causes acquired microphakia?

A 
Zonular disorders (insufficient traction)
think about terriers...
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the 2 types of lens colobomas? How do they get classified as such?

A

Typical: 6 o’clock
Atypical: anywhere else

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

Lens colobomas are often associated with a coloboma WHERE?

A

Uvea

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

What can occur if there is an extensive coloboma?

A

Lens luxation

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

What common lens disorder is often associated with lens colobomas (of any size)?

A

Cataract

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

What is the embryological basis of PPMs?

A

They are remnants of the anterior tunica vasculosa lentis

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

How long does the anterior pupillary membrane remain in the dog?

A

14 days after birth

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

Are PPMs generally considered hereditary?

A

NO

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

What breed are PPMs commonly considered hereditary?

A

Basenji

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

What disorder is commonly associated with PPMs?

A

Cataract

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

What finding on the SURFACE of the lens is attributed to remnants of the pupillary membrane?

A

Pigment

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

What 2 breeds commonly get pigment on their lens from pupillary membrane remnants?

A

Doxies, Cairn Terriers

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

Why is PHTVL/PHPV considered bad?

A

Commonly associated with cataract

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

How many grades of PHTVL/PHPV exist?

A

Six (1 being the least affected)

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

What is the difference btwn lenticonus and lentiglobus?

A 
Lenticonus = cone like
Lentiglobus = spherical
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where can lenticonus/globus occur on the lens? What location is most common?

A

Posterior cortex/capsular regions, into the vitreous body

Also can see anteriorly and axially

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

What is lenticonus internum?

A

Lens nucleus extends into posterior cortex

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

Review CONGENITAL abnormalities that can be associated with cataracts

A
  1. Congenital cataract (alone)
  2. Lens coloboma
  3. PHTVL/PHPV and PPMs
  4. Lenticonus/lentiglobus
  5. Multiple ocular abnormalities
  6. Oculoskeletal dysplasia (form of MOA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where are congenital cataracts usually seen? Progressive?

A

FETAL NUCLEUS

non-progressive, but can involve adjacent anterior/posterior cortex

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

What are 3 potential causes of congenital cataracts?

A
  1. Hereditary
  2. Toxin exposure in utero
  3. Infectious agent exposure in utero
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How are most cataracts inherited?

A

Autosomal recessive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What 2 breeds of dog have incomplete dominant inheritance of cataracts?

A

Chesapeake Bay Retriever

GSD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What breed has autosomal DOMINANT inheritance of cataracts?

A

Norwegian Buhund

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What 2 breeds have triangular, posterior polar cataracts?

A

Golden, Lab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What 2 changes are seen histologically indicating a lens rupture?

A
  1. Curled lens capsule

2. Intralenticular leukocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are bladder cells? Appearance?

A

Swollen lens epithelial cells

Balloon-like (increased particulate matter in cytoplasm), usually in LENS BOW region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What change is often seen histologically with posterior cataract?

A

Migration of epithelial cells along posterior lens capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are Morgagnian globules? How do they appear?

A

Lytic lens proteins

Basically aggregates of eosinophilic lens proteins in aggregates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Wha 3 locations are most commonly associated with incipient cataracts?

A
  1. Cortex
  2. Subcortical
  3. Y-suture
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What change to the anterior/posterior capsule is commonly seen with HYPERMATURE cataracts?

A

Plaque formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What age of dog most commonly develops Morgagnian cataracts?

A

<1 year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the anterior extent of Cloquet’s canal called?

A

Mittendorf’s dot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Punctate lens opacities have been found in what percentage of dogs?

A

30-40%

37
Q

What is the progression of Y-suture cataracts?

A

Often disappear

38
Q

How many breeds of dogs are THOUGHT to have hereditary cataracts?

A

> 160 breeds

BUT very few have been proven

39
Q

What signalment is most common with hereditary cataracts?

A

Pure bred dog, young to middle aged

40
Q

What 2 breeds get oculoskeletal dysplasia (which is associated with cataracts)

A

Lab, Samoyed

41
Q

What 2 gene mutations are associated with oculoskeletal dysplasia?

A

COL9A2 and COL9A3

42
Q

Describe metabolic pathway leading to diabetic cataracts

A

High levels of glucose in lens –> saturate hexokinase pathway –> shifted to polyol pathway –> aldose reductase turns glucose into sorbitol –> sorbitol doesn’t diffuse out of lens –> osmotically pulls water into lens –> lens fibers swell and rupture, vacuoles form, etc –> sorbitol can also be oxidized into fructose via sorbitol dehydrogenase

43
Q

What happens to aldose reductose in diabetic animals (specifically, there is something different with this enzyme over normal)

A

Increases in amount

44
Q

What percentage of diabetics will develop cataracts at 6 months? 1 year? 15 months?

A

50%, 75%, 80%

45
Q

Spontaneous lens capsule rupture occurs most commonly in what location?

A

Equatorial

46
Q

Multifocal punctate cataracts that are bilaterally symmetrical are associated with what electrolyte disorder (and what systemic diseases?)

A

Hypocalcemia

[renal failure, primary or secondary hypoparathyroidism]

47
Q

Treatment of hypocalcemia– can it affect cataracts?

A

May prevent progression, but won’t resolve what is there

48
Q

What LOCATIONS (2) is most commonly seen with TOXIC cataracts?

A

Anterior and posterior cortex near the EQUATOR (area of lens fiber elongation) OR at Y-suture

49
Q

What appearance is usually associated with toxic cataracts?

A

Vacuoles

50
Q

What anti fungal can cause cataracts?

A

Ketoconazole

51
Q

What administration of ketoconazole is commonly associated with cataracts?

A

Chronic (>4-37 months)

52
Q

What is the most common TOXIC form of cataract seen clinically?

A

Secondary to PRA or other types of retinal degeneration

53
Q

What 3 breeds most commonly have cataracts associated with their PRA?

A

1) Lab
2) Mini poodle
3) Toy poodle

54
Q

What is the progression of retinal degeneration-associated cataracts?

A

They will eventually affect the entire lens

55
Q

What nutritional deficiency is associated with cataracts?

A

Arginine

56
Q

What location is most associated with traumatic cataracts?

A

Anterior SUBCAPSULAR

57
Q

What are other signs that the cataract may have been traumatic?

A
  1. Iris pigmentation on lens (esp if blunt trauma)
  2. Corneal scar over similar location
  3. Cataract progressively gets “deeper” as more lens fibers are added to lens
  4. Unilateral
58
Q

If a traumatic cataract occurs over a lens suture, what is the appearance?

A

Stellate

59
Q

Why do dogs and rabbits seal their lens rents so well?

A

They have a fibrinous anterior uveitis

60
Q

What size rent to the lens capsule suggests it should be removed (or else risk severe phacoclastic uveitis?)

A

1.5 mm+

61
Q

What metal is usually well tolerated if it enters the lens? What metals are not well tolerated?

A

Lead

ANY other metal = usually not well tolerated (esp steel and iron)

62
Q

What is the risk if an oxidizing metal (steel, iron, copper, zinc, brass) are left in the eye?

A

Panophthalmitis

63
Q

What type of cataract is associated with electrocution/lightening strike? Are they progressive?

A

BILATERAL anterior subcapsular

Usually PROGRESSIVE

64
Q

When are cataracts usually seen with ionizing radiation?

A

> 6 months from initial exposure

65
Q

What arbitrary ages are usually used to assign senile cataracts?

A

> 6 yr small breed

>10 yr large breed

66
Q

What location and appearance is commonly associated with senile cataracts?

A

NUCLEAR, punctate to linear

67
Q

What appearance (2) is commonly associated with senile cataracts OUTSIDE of the nucleus (i.e. in the cortex)?

A

Wedge-shaped or spoked

68
Q

What is the long-term prognosis for vision with senile cataracts?

A

Good–usually very slow progression and never appreciably affect vision

69
Q

What percentage of dogs will develop some sort of lens opacity?

A

ALL of them (senile cataracts eventually if live long enough)

70
Q

What is the common location for uveitis-induced cataracts?

A

equatorial or anterior/posterior subcapsular

71
Q

How bad does uveitis need to get to cause a cataract?

A

Moderate to severe

72
Q

What percentage of dogs will develop phacolytic uveitis?

A

~70% (if not treated)

73
Q

What is the risk of glaucoma secondary to phacolytic uveitis?

A

Has not been definitely documented

74
Q

What are 2 common ways to develop phacoclastic uveitis?

A
  1. Intumescent cataract that ruptured

2. Traumatic lens rupture/lens implantation syndrome

75
Q

What is the prognosis for phacoclastic uveitis?

A

POOR– generally does not respond well to anti-inflammatories

76
Q

Why is phacoclastic uveitis usually worse than phacolytic?

A

Phacolytic: only recrystallized lens proteins
Phacoclastic: membrane-associated antigens also present

77
Q

What percentage of the lens needs to be affected before demonstrable vision loss is seen?

A

40-50%, and usually BOTH lenses!

78
Q

How long is a menace maintained with cataracts?

A

Usually to near completion of cataract

79
Q

Why do some dogs sometimes see better in the dark if they have cataracts?

A

Pupil is dilated

80
Q

Spontaneous resorption of a cataract is usually seen in what 4 breeds?

A
  1. Toy poodle
  2. Miniature poodle
  3. Miniature Schnauzer
  4. American Cocker
81
Q

What 2 complications are higher with hyper mature cataracts?

A
  1. Vitreal degeneration and retinal detachment

2. Lens subluxation/luxation

82
Q

With a lens luxation, if there is associated corneal edema, will it resolve?

A

It may, or it may be permanent

83
Q

What is more likely to lead to anterior uveitis: anterior lens luxation or posterior?

A

Anterior

84
Q

What is more likely to lead to pupil block glaucoma: anterior or posterior lens luxation?

A

Anterior

85
Q

What gene is associated with primary lens luxation?

A

ADAMTS17

86
Q

How is primary lens luxation inherited?

A

autosomal recessive

87
Q

What age range is primary lens luxation seen?

A

3-6 yrs

88
Q

What is the likelihood that blunt trauma caused a lens luxation?

A

Unlikely, if that is the only thing seen

89
Q

In PLL dogs managed with miotics, what percentage had vision at 1 year and 2 years?

A

1 year: 80%

2 years: ~60%

new (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions