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BVetMed4 - Optho > The Opaque Eye - Intraocular Disease > Flashcards

The Opaque Eye - Intraocular Disease Flashcards

1
Q

What is found at the centre of the lens?

Should you be able to see it in the normal eye?

A

Nucleus

No

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2
Q

What is the lens attached to?

A

The ciliary body

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3
Q

What causes nuclear sclerosis?

A

Lens nucleus becomes compact and dense with aging

DOES NOT CAUSE BLINDNESS

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4
Q

What clinical signs are associated with lens disease?

A

Decreased transparency - cataract

Phacodenesis - lens luxation
Iridodonesis - trembling iris
Aphakic crescent - lens subluxation

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5
Q

What can cause diseases of the lens ?

A

Congenital abnormalities
Cataract
Lens induced uveitis
Lens luxation

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6
Q

What congenital abnormalities can cause lens disease?

A

persistent blood vessels
Microphakia - small lens
Lens coloboma - hole in lens

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7
Q

Define the term cataract

A

Any non-physiologic opacity in the lens

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8
Q

What is the most common cause of cataracts?

A

Diabetes Mellitus

DOGS usually develop within 2y of diabetes diagnosis

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9
Q

What is the second most common cause of cataracts?

A

Progressive Retinal Atrophy (PRA)

Retina degenerates releasing toxins (glutamate) -> cataract formation

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10
Q

What drug could prevent the formation of diabetic cataracts?

A

ALDOSEREDUCTASE

Prevents sorbitol formation

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11
Q

What is key on exam to detect and identify cataracts?

A

Retro illumination

- defects appear black against light background

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12
Q

What is an incipient cataract?

A

Less than 10-15% lens volume

Y shape

Vision minimally affected

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13
Q

What are immature cataracts?

A

Nuclear and cortical regions affected (more than 30% affected)

Tapetal reflex still visible

Decreased vision especially at night

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14
Q

What are mature cataracts?

A

Complete opacity of the lens - marble white appearance

NO TAPETAL REFLEX

BLIND

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15
Q

What is a hyper mature cataract?

A

Small crystalline particles from degraded lens

Wrinkled anterior lens capsule
Lens may decrease in size

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16
Q

What is a morgagnian cataract?

A

Advanced lysis and liquefaction of lens fibres

Solid nucleus might gravitate centrally - DROPPED nucleus

17
Q

What causes lens-induced uveitis?

A

Proteins leak through lens capsule during cataract maturation

CS - reduced IOP
Resistance to pharmacological dilation
Iris dark colour

Tx early cataracts with antiinflammatories

18
Q

What type of uveitis may be seen in advanced cataracts ?

What cause makes this more likely?

A

PHACOLYTIC
- spontaneous lens rupture (RARE)

Diabetic

19
Q

What is a potential downside to cataract surgery in dogs?

A

Need life long anti-inflammatory pos surgery

20
Q

When do you see iridodonesis?

A

If the lens isn’t there to give it stability

21
Q

What causes primary lens luxation?

A

Anomalous zonules

Terriers

22
Q

What causes secondary lens luxation?

A

Chronic inflammation
Glaucoma
Intra ocular mass
Trauma

23
Q

What is pathognomonic of a lens luxation on retroillumination?

A

Aphakic crescent

24
Q

what is the goal of glaucoma treatment ?

A

To prolong to process- will eventually go blind as it is IRREVERSIBLE

25
Q

Why does glaucoma occur?

A

Blocked outflow - problem with aqueous drainage

  • primary - genetic
  • secondary to ocular disease
26
Q

What concurrent ocular diseases can lead to glaucoma ?

A

Uveitis
Lens luxation
Intraocular tumour
Cataract - can leak and cause inflammation

27
Q

What clinical signs are associated with acute glaucoma ?

A 
Corneal oedema 
Episcleral congestion 
Conjunctival hyperaemia 
Epiphora 
MYDRIASIS 
Aqueous flare 
Absent menace
28
Q

Why is MYDRIASIS associated with glaucoma?

A

increased intraocular pressure

29
Q

What clinical signs are associated with chronic glaucoma ?

A 
Corneal oedema 
Optic nerve head cupping 
Hab’she striae (Stretch marks on eye)
Bupthalmia 
Lens subluxation 
Episcleral congestion 
Conjunctival hyperaemia 
Epiphora 
MYDRIASIS 
Aqueous flare 
ABsent menace and blindnes
30
Q

What is buphthalmos ?

A

Enlargement of the eye

31
Q

What is gonioscopy?

A

Direct viewing of the drainage angle

32
Q

What can you give to patients with uveitis to prevent glaucoma?

A

ATROPINE

Opens pupil and stops iris getting stuck to lens

33
Q

How can pupil size help differentiate between uveitis and gaucoma?

A

Small pupil - uveitis

Large - glaucoma

34
Q

How can you medically manage glaucoma?

A

Prostaglandin analogues to increase out flow (drops)

Carbonic anhydrase inhibitors to reduce aqueous production by ciliary body

35
Q

How can you surgically manage glaucoma?

A

Laser cyclophotocoagulation
Aqueous shunt placement
Enucleation

36
Q

If there is wobbling inside the eye what should you consider?

A

Lens luxation

37
Q

Why is there less of an inflammatory response in the eyes of cats in general?

A

Have a better blood aqueous barrier

BVetMed4 - Optho (8 decks)

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