Lecture 3 Flashcards

1
Q

what is this

A

iris atrophy. not a persistent pupillary membrane because it does not originate from the collarette

also a mature cataract in the lens

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

explain what iris atrophy is

A

a senile old age loss of iris tissue where the pupillary margin starts to look moth eaten, creating dyscoria (abnormal pupil shape). if it’s severe it can cause PLR deficit

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

what is this?

A

iris atrophy, can see the pupil on the right side of the picture and then a bunch of holes and moth eaten appearance. this dog is likely old.

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

what is this? what treatment is required?

A

uveal cyst (in the anterior chamber in front of the iris). these are benign and not painful at all

no treatment is required as long as it doesnt affect vision, but you can do a laser ablation or aspirate with a 27G needle if you want

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

what breeds like to get uveal cysts?

A

goldens, labs, boston terriers

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

what is this

A

hyphema: blood in the anterior chamber

usually just from disease in the eye but can be from systemic disease too

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

what is this? treatment and prognosis?

A

hyphema: complete filling of anterior chamber with blood secondary to a globe rupture. this eye has zero prognosis for vision and the eye needs to come out

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

what are the causes of hyphema?

A

trauma: intraocular tumors, retinal detachment, anterior uveitis
systemic: leukemia or polycythemia, clotting abnormalities, circulatory disorders (hypertension)

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

what is this

A

iris melanoma: multifocal areas of iris hyperpigmentation

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

the most common primary intraocular tumor in cats is

A

iris melanoma

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

does iris melanoma in cats like to spread/metastasize?

A

no they usually dont spread

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

if iris melanoma in a cat progresses enough, it can cause…

A

anterior uveitis, glaucoma, ocular discomfrt and vision loss

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

how will you treat this cat

A

iris melanoma

can watch/monitor for changes and measure IOP

can do a laser ablation of the pigmented lesions

take the eye out when glaucoma occurs or if there’s diffuse changes noted

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

what is this

A

iris melanoma

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

what is this? what is the prognosis?

A

iris melanoma, diffuse pigmentation everywhere on the iris.pigment is also now on the anterior lens capsule and it is “too late” and if the cat doesn’t already have glaucoma it will get it :(

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

what is buphthalmia?

A

enlargement of the eye associated with glaucoma

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

10 yo border collie acutely blind but owners said his eyes have been abormal for a while. he has no menace, dazzle, or PLRs. IOP OD 40 and OS 62. Diagnosis?

A

glaucoma: elevated IOP with damage to the optic nerve

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

the aqueous humor is produced by the _____

A

ciliary body by the non pigmented epithelium

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

normal IOP is

A

15 to 25

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

describe the normal flow of the aqueous humor

A

produced by the ciliary body then goes into the posterior chamber (between the iris and the lens) and thru the pupil into the anterior chamber. then it flows to the iridocorneal angle (ICA) which is where the base of the iris meets the cornea and sclera.

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

what are the 2 different ways in which the aqueous humor can flow out of the eye?

A

conventional outflow: this is how 85% of the aqueous humor exits, flows thru the corneoscleral trabecular meshwork and this is where the majority of the resistance happens. It’s sort of like a seive for the flud, slows it down. it then goes into collecting veins

nonconventional outflow: thru uveoscleral outflow and thru the sclera. this is INDEPENDENT of IOP and is driven by OSMOSIS, then goes into systemic circulation.

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

he most frequent cause of irreversible blindness in dogs is

A

glaucoma

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

true or false: glaucoma can be caused either from increased production of the aqueous humor or a laxck of outflow

A

FALSE it is only due to decreased outflow, NEVER from over production

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

what is goniodysgenesis?

A

a predisposition to glaucoma/primary cause of glaucoma; the normal pectinate ligaments and spaces between them for the aqueous humor to flow through fail to form and the ICA becomes smaller, making it difficult for the aqueous humor to outflow. usually affects both eyes at different times

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

true or false: the prescence of gondiodysgenesis indicates glacuoma will develop later in life

A

false! most of the time they do but it’s no ensured

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

list at least 3 breeds predisposed to gondiodygenesis

A

atika, shiba inu, chow chow, beagle, husky, dalmation, GSD, etc

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

true or false: congenital primary causes of glaucoma are rare

A

truel

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

list some secondary causes of glaucoma

A

anterior lens luxation (prevents normal outflow)
anterior uveitis (debris and cells plug everything up)
intraocular neoplasia
hyphema
retinal detachment

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

true or false: most cases of glacuoma occur chronically

A

false, most cases occur acutely

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

glaucoma destroys which cells?

A

ganglion cells and the optic nerve leading to loss of vision

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

how quickly can vision be lost in acute cases of glaucoma?

A

in less than 1 day, necrosis and apoptosis of the ganglion cells in the retina occurs, and by day 7 there will be end stage retinal atrophy

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

what are the 3 effects of an elevated IOP?

A

ischemic damage

compressive damage to axons (can be reversible if caught early)

later degeneration: lamina cribosa gets pushed and you get optic nerve cupping, this is irreversible blindness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

why does increased IOP cause mydriasis?

A

axon compression in the retina and optic nerve, ischemic damage to the iris sphincter muscle initially, and chronic atrophy of the iris stroma

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

why does increased IOP cause corneal edema?

A

the aqueous humor is pushed into the cornea from pressure, and the endothelial cells alter in function; they are no longer able to pump water out and eventually die off with chronicity

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

list some chronic changes of elevated IOP

A

buphthalmia (globe gets stretched from pressure)
Haab’s striae: stretch marks in descemet’s membrane
lens subluxation: globe enlargement causes zonules to stretch, usually a posterior lens luxation when glaucoma is the primary cause

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

why is glaucoma painful?

A

the globe stretches and this hurts!! but signs can be subtle: irritability, decreased appetite, sleeping more, hiding.

37
Q

how do you tell if glacuoma is primary or secodnary?

A

you need to use gonioscopy to assess the iridocorneal angle

38
Q

when presented with a glaucoma patient what are some questions you want to answer?

A

is vision present? do dazzle and menace
how long has the pressure been elevated?
are there signs of chronicity?

39
Q

the goal of emergency glaucoma therapy is

A

to reduce the IOP quickly to reduce damage to the retina and optic nerve

40
Q

with a glaucoma patient, we want to reduce the pressure to

A

<10mmHg ideally

41
Q

describe medical management for glaucoma

A

carbonic anhydrase inhibitors: reduces aqueous production
prostaglandins: increase outflow

sometimes: beta blockers, parasympathomimetics

42
Q

what are some side effects of using beta blockers to treat glaucoma?

A

can reduce ability to heal epithelial defects

contraindicated in patients with lower airway disease or heart failure

doeesnt work well by itself, better as add on tx

43
Q

which drug can be used on an emergency basis (or for more chronic use) for glaucoma that can work as fast as 30 minutes?

A

prostaglandin analouges: Xalatan (lantanaprost)

44
Q

which drug is good for long term glaucoma treatment but can be irritating?

A

carbonic anhydrase inhibitors like dorzolamide

45
Q

why doesnt brian like using mannitol for glaucoma?

A

you have to give it IV and essentially dehydrate the patient and therefore dehydrate the vitrous. it requires hospitalization.

46
Q

when should surgical therapy for glaucoma be considered?

A

patients that become refractory to medical treatment or not respond at all

47
Q

if surgery for glaucoma is to be done, it needs to be done when?

A

before significant optic nerve damage has occured

48
Q

what are the surgery options for glaucoma?

A

laser cyclophotocoagulation: damage the ciliary body to decrease fluid production, this is best for long term treatment

gonioimplant: a drainage procedure ith poor long term succes, tends to fail in 3-4 months

49
Q

in a patient with glaucoma that is already blind, what treatment options are there then?

A

we just need to keep the patient comfortable, so use medical therapy to keep the IOP below 35. if you can’t do this, then you either need to do an enucleation or an evisceration

50
Q

what is a nice option for older dogs with chronic glaucoma that are at risk for undergoing GA?

A

intravitreal gentamicin injection: damages ability to produce aqueous and can be done with just IV sedation/anesthetic.

51
Q

if one eye has really bad glaucoma how can you prophylactically treat the other eye?

A

can use dorzolamide (carbonic anhydrase inhibitor)

52
Q

a cataract is

A

an opacity of the lens

53
Q

if a cataract is severe enough it will

A

prevent light from reaching the retina and can impair vision

54
Q

briefly describe the classifications of cataracts

A

incipient: small dit dots
immature: more diffuse, tapetal reflex still present
mature: diffuse cloudiness and no more tapetal reflex, vision lost
hypermature: tapetal reflex comes back, lens is liquifying

55
Q

what are these?

A

incipient cataracts

56
Q

what dis

A

immature cataracts, can still see tapetal reflection!

57
Q

true or false: even if you can see the back of the eye and do a complete fundic exam, surgery is still a good option for treating cataracts

A

false! only do surgery if you CANNOT visualize the fundus and the tapetal reflection is gone

58
Q

what is this?

A

a late immature cataract, still tapetal relfection and its hard to see he fundus but still possible

59
Q

what is a hypermature cataract?

A

where the lens material liquifies and leaks into the eye, usually associated with anteiror uveitis and wrinkling of the lens capsule

60
Q

what dis

A

mature cataract (no tapetal reflection)

61
Q

what dis

A

hypermature cataract, tapetal reflection is back

62
Q

____% of dogs with diabetes will develop cataracts will develop within 5-6 months from the time of diagnosis

A

50

63
Q

why does diabetes cause cataracts?

A

glucose overwhelms glycolysis pathways and is shunted into the sorbitol pathway and sorbitol struggles to leave the lens and draws in water and damages the lens fibers.

64
Q

why dont cats with diabetes get cataracts?

A

they have low levels of the enzyme that converts glucose to sorbitol

65
Q

what is this

A

a cataract with anterior lens capsule rupture. this can happen diabetic patients get cataracts really quickly

66
Q

what causes cataracts?

A

genetic: really common in dogs, uncommin in cats
age
congenital: uncommon
uveitis: in horses and cats
nutritional: puppies on poor milk replacement

67
Q

what medical treatment is available for cataracts?

A

SIKE nothing beech

68
Q

how can you prevent cataracts from forming in diabetic patients?

A

aldose reductase inhibitors: kinostat or ocu-GLO

you MUST keep using it bc if you stop, cataracts can develop in 2 weeks of stopping

69
Q

what is the most effective treatments for cataracts?

A

surgery: phacoemulsification and lens replacement

70
Q

this dog is 13. what is this?

A

nuclear sclerosis: central hazy area

71
Q

explain what nuclear sclerosis is

A

hardening and increased density of the nucleus of the lens, a normal age related change, the lens gets hazy but not opaque

72
Q

wot dis

A

anterior lens luxation with a cataract in the lens

73
Q

wot dis

A

lens subluxation: aphakic crescent present, zonules missing on one side

74
Q

which lens luxation will you see the aphakic crescent?

A

posterior subluxation

75
Q

what is iridodonesis and phacodenesis?

A

iridodonesis: when the iris wiggles with eye movement
phacodonesis: when the lens wiggles with eye movement

76
Q

list causes of lens luxation

A

primary: genetic, terriers and heelers, a specific gene
secondary: glaucoma, chronic uveitis (cats), trauma, age, anything causing zonules to breakdown

77
Q

primary lens luxation and secondary glaucoma will present…

primary glaucoma and secondary lens luxaion will present…

A

no buphthalmia and aterior luxation

buphthalmia and posterior luxation

78
Q

how do you treat lens luxation (each type)?

A

subluxation: meds to induce miosis (xalatan or latanoprost
posterior lux: induce miosis
anterior: remove the lens asap especially if increased IOP

79
Q

wot dis

A

asteroid hyalosis: opacities behind the lens from either cholesterol or calcium. causes no problems and no treatment is needed

80
Q

what is syneresis?

A

liquifaction of the vitreous seen as swirling cotton candy. no treatment needed

81
Q

what is seen here?

A

areas of increased reflectivity on the right side=progressive retinal atrophy

82
Q

what causes progressive retinal atrophy?

A

a group of inherited, acquired photoreceptor diseases

will be night blind first (nyctalopia) since rods lost first, and then eventual blindness when cones are gone

will see mydriasis and cataracts

83
Q

clinical signs of sudden acquired retinal degeneration and what causes it?

A

poor PLRs, the retina looks normal

we dont know the cause and theres no treatment

84
Q

wot dis

A

chorioretinitis: inflammatory granules from blasto underneath the retina, can cause eventual retinal detachment

85
Q

wot dis

A

chorioretinal scar (flat and no raised like chorioretinitis)

hyperreflective area with focal hyperpigmentation

86
Q

wot dis

A

chorioretinal scars

87
Q

wot dis

A

a cat with underlying kidney disease and their retina detaches

88
Q

difference between buphthalmia and exopthalmia?

A

buphthalmia: enlargement of the eyeball
exophthalmia: abnormal protrusion of the eyeball

buphthalmia: globe size is enlarged, IOP will be elevated, retropulsion is normal, and vision absent

exopthalmia: globe size normal, IOP normal, retropulsion is reduced, and vision is present