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CLIN SCI 4 EX2 > Glaucoma > Flashcards

Glaucoma Flashcards

1
Q

Normal IOP is

A

10-25mmHg (dogs + cats)
10-30mmHg (horses)

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2
Q

IOP is a balance between

A

production (ultrafiltration, simple diffusion, active secretion) and aqueous drainage

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3
Q

What is the flow of aqeuous humor

A

ciliary body
posterior chamber
pupil
anterior chamber
iridocorneal angle

IOP is needed to maintain eye shape

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4
Q

What causes obstruction of aqueous humor outflow

A

Primary: closed/narrow iridocorneal angle (ICA)

secondary to: uveitis, intraocular tumor, lensluxation

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5
Q

Increased IOP leads to

A

-optic nerve degeneration
-retinal degeneration (retinal atrophy)
-blindness

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6
Q

What are the clinical signs of glaucoma

A

-Corneal edema (water in the cornea (blue hazy cornea)
-Episcleral injection
-Mydriasis
-Blepharospasm
-Epiphora

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7
Q

With glaucoma is the pupil small or large

A

large (mydriasis)

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8
Q

What clinical signs tell you that glaucoma is chronic

A

1) Buphthalmos (enlarged eye)
2) Corneal striae, Haab’s striae= lines/stretch marks in the cornea
3) Lens subluxation = dislocation of the lens
4) Mydriasis
5) Cupped optic nerve head (optic nerve degeneration)
6) Tapetal hyperreflectivity
7) Retinal vascular attenuation (thinning of blood vessels)

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9
Q

line / stretch marks in the cornea seen with chronic glaucoma

A

Corneal striae, Haab’s striae

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10
Q

Increased IOP causing blindness by

A

optic nerve becomes degenerated and cupped and causes blindness

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11
Q

T/F: primary glaucoma is common in cats and horses

A

false

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12
Q

What breeds commonly get primary glaucoma

A

Cockerspaniels**
Basset hounds
Beagles (open angle)
Chow Chows
many more

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13
Q

How does glaucoma typically develop

A

sudden onset pressure spike
generally unilateral in the initial stage
-other good eye is affected ~9months after the first eye if no drugs
-31 months after the first eye if started on anti-glaucoma drugs

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14
Q

OD IOP=62mmHg and blind
OS IOP= 12mmHg and visual
What would you do as an ER doctor who sees this dog Saturday morning- owner says the dog (6yo Basset FS named Rose was visual the night before)
What do you do

A

Decrease IOP ASAP

Latanoprost OD 1 drop
-Repeat q10-15min x3
-Repeat IOP (tonometry) after an hour

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15
Q

What causes IOP spike in primary glaucoma

A

-Inherited narrow/collapsed ICA
-Sudden complete collapse of ICA

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16
Q

narrow/closed iridocorneal angle
-sign of primary glaucoma

A

goniodysgenesis

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17
Q

procedure to differentiate between primary and secondary glaucoma

A

gonioscopy

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18
Q

what would goniodysgenesis look like when doing gonioscopy

A

pectinate ligament cant be seen- will be darker line and have a closed angle

19
Q

What species does secondary glaucoma effect

A

any species

20
Q

What is the most common cause of secondary glaucoma ***

A

anterior uveitis

21
Q

What are the 4 causes secondary glaucoma

A

1) Anterior uveitis
2) Lens luxation
3) Intraocular tumor
4) Intumescent cataract (swollen lens - most often due to diabetic cataracts)

22
Q

What are the clinical signs of secondary glaucoma

A

-Pain: epiphora and blepharospasm
-Decreased to absent vision
-Episcleral injection (red)
-Cloudy eye (corneal edema, anterior uveitis)

23
Q

What are the clinical signs of glaucoma secondary to uveitis

A

-Episcleral injection
-Perilimbal corneal edema
-Diffuse corneal edema
-Miotic pupil
-Potential oris bombe
-Hyphema or hypopyon
-IOP will be high normal (because glaucoma has high IOP and uveitis has low IOP) -> very alarming

24
Q

How do you diagnose glaucoma

A

Tonometry with a Tonometer
1) Applanation Tonometry (Tonopen)
2) Rebound Tonometry (TonoVet)

10-25mmHg (dog/cat)
10-30mmHg (horse)

25
Q

How do you decide primary vs secondary glaucoma

A

-breed,signalment
-underlying cause
-gonioscopy (referral to ophthalmologist)

*Treatment may differ greatly for primary glaucoma

26
Q

How do you treat acute onset, primary glaucoma

A

Decrease IOP ASAP to save vision
only a few hours of high IOP to save vision

1) Prostaglandin analogues:
Latanoprost and Travoprost - strong effect
2) Carbonic anhydrase inhibitors (Dorzolamide)- medium effect
3) Beta-blockers (Timolol) mild effect

27
Q

What are the prostaglandin analogues used as emergency treatment for primary glaucoma

A

Latanoprost and Travoprost

28
Q

Cosopt

A

combined Dorzolamide (carbonic anhydrase inhibitor) with Timalol (beta blocker) for glaucoma treatment

29
Q

you have a 3yo MN pointer
was in northern part of US one week ago for hunting
started to have a red eye a couple days ago
Squinting OD
seems a little tired too and did not eat his dinner yesterday or breakfast this morning
OD:
IOP 27mmHg
corneal edema, perilimbal corneal vascularization, episcleral injection, miotic pupil, uveitis,
OD still visual
what do you do

A

Find underlying cause of secondary uveitis
-Infection (CBC/Chem/UA/Titers/4DX)
-Neoplasia (chest xray, abdominal ultraosund, spinal tap, skull MRI)
Immune mediated

Treatment:
-Topical steroids (1% prednisone)
-Dorzolamide BID-TID

Maybe
-Atropine (when IOP is normal)
-Sysemic steroids or NSAIDs are diagnostics
-Systemic antibioitcs (Doxy)
-Systemic antifungal (Itraconazole or fluconazole)

recheck IOP in one day and start on topical atropine SID-TID and recheck in 7-10 days

30
Q

What is contraindicated in glaucoma eyes

A

Atropine

31
Q

How do you treat secondary glaucoma due to anterior lens luxation

A

-Emergency SX
1) Decrease IOP- Mannitol to dehydrate vitreous
2) Remove lens or eye (enucleation) or trans-corneal lens reduction *

surgery dependent on vision - consensual PLR

32
Q

What surgeries can be done for primary glaucoma

A

1) Gonio shunt/valve
2) Trans-scleral laser (decreases production of cilirary body)
3) Endolaser - burning ciliary body from the inside

33
Q

What should you do for end-stage blind eye due to glaucoma

A

1) Enucleation- 100% success rate
or
2) Exenteration (removal of globe and surrounding tissue)
in case of extra or intraocular infection or neoplasia
3) Evisceration: globe content removal
keeps: sclera, cornea, third eyelid, eyelids, glands
(primary only)
4) Ciliary body chemical ablation

34
Q

What is the side effect of evisceration

A

corneal ulcers, dry eye, abnormal appearance

globe content is removed but sclera, cornea, third eyelid, eyelids, and glands are kept (no tapetum reflection)

35
Q

Ciliary body chemical ablation

A

tx for primary glaucoma
Intravitreal injection of cidofovir or gentamycin which is toxic to the ciliary body and will stop the production of aqueous humor

side effects:
inflammation- continue topical anti-inflammatory
phthisis bulbi (small globe) which could cause entropion

36
Q

What are the side effects of ciliary body chemical ablation

A

1) inflammation- continue topical anti-inflammatory
2) phthisis bulbi (small globe) which could cause entropion

37
Q

ciliary body chemical ablation is only for

A

primary glaucoma

38
Q

For blind eye glaucoma, when do you consider evisceration

A

owner wants the appearance of dog having an eye

39
Q

For blind eye glaucoma, when do you consider exenteration instead of enucleation

A

extra- or intraocular infection or neoplasia

40
Q

removal of the globe

A

enucleation

41
Q

removal of the globe and surrounding tissue
used incase of extra or intraocular infection or neoplasia

A

Exenteration

42
Q

globe content removal but sclera, cornea, third eyelid, eyelid, and glands are kept

A

Evisceration

43
Q
A

CLIN SCI 4 EX2 (5 decks)

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