Final: Ophthalmology - Lens, Glaucoma, Fundus Flashcards Preview

SAM 2 scs RUSVM > Final: Ophthalmology - Lens, Glaucoma, Fundus > Flashcards

Flashcards in Final: Ophthalmology - Lens, Glaucoma, Fundus Deck (39)
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1

What is the therapy for cataracts?

Topical NSAIDs and corticosteroids (to help control/prevent lens-induced uveitis)

Phagoemulsification - sx where lens is broken up using ultrasound energy and aspiration

2

What is the therapy for lens induced uveitis?

Topical +/- systemic anti-inflammatories

3

What is the etiology of lens luxation? How is it treated?

Primary: Inherited (Terrier breeds) causng abnormal degeneration of zonular ligaments; more common in dogs

Secondary: Chronic uveitits (most common in cats), trauma, chronic glaucoma (enlargement of globe can stretch/break zonular ligaments)

4

When is latanoprost indicated with lens instability? When is it counterindicated?

Indicated: Anterior lens luxation when surgery IS NOT possible, subluxation

C/O'd: Anterior lens luxation when surgery IS possible

Latanoprost = Miotic to trap lens

5

What is the term for the hardening of the lens that occurs naturally in animals and causes increased reluceny such that the lens appears cloudy? At what age is it evident in dogs and cats?  Does it cause vision loss? 

Nuclear sclerosis

7 yrs

Does not cause vision loss

6

What is a cataract?

Any opacity of the lens or lens capsule

7

What is used to determine where the opacity is located in the lens?

Parallax - using the appearance of one object relative to another to determine depth

8

Where do lens zonules attach? What are they?

Equator of the lens

Small collagen fibrils arising from ciliary body that secure the lens' position within the eye (ligaments of the ciliary body)

9

What type of cataract formation is driven by osmotic effects due to entrapped sorbital (converted from glucose by aldose reductase) and fructose in the lens capsule? What animals is this type common in?

Intumescent cataract

Diabetics

10

When do you see an aphakic crescent?

Lens subluxation

11

What is the movement of the iris that occurs secondary to lens instability? What about the movement of the lens secondary to lens instability?

Iridonesis

Phacodonesis

12

Cataract or nuclear sclerosis:

Can see the fundus through a lens attenuation 

Can see fundus around a lens attenuation

Nuclear sclerosis: Can see the fundus through a lens attenuation 

Cataract: Can see fundus around a lens attenuation

13

What is the most common cause for cataract formation in dogs? Cats and horses?

Dogs: Inherited

Cats, Horses: Chronic uveitis 

14

Dogs with ____ will lose rod photoreceptor function and display ____ blindness, often before developing ______. 

Progressive retinal atrophy (PRA)

Night

Cataracts

 

Important to exclude retinal disease as an etilogy of cataract prior to pursuing cataract surgery

15

What are the 2 types of lens-induced uveitis? Which is more severe and how are they caused?

Phacoclastic (more severe)- caused by traumatic tears of the lens capsule

Phagolytic (milder)- leakage of lens proteins from a cataract

16

What is the treatment for anterior lens luxation in a visual or potentially visual eye?

First medically stabilize- decrease IOP (Mannitol, Dorzolamide)

If connot contril IOP = surgical emergency 

17

Where is aqueous humor formed? What is its path to drainage within the eye?

Ciliary body (aided by Carbonic anhydrase)

Ciliary body -> Posterior chamber -> Pupil-> Anterior chamber -> Iridocorneal angle (or Uveoscleral angle) -> Venous drainage

18

What are the clinical signs associated with glaucoma?

Episcleral injection (Red eye)

Pain, Blepharospasm

Cloudy eye (Corneal edema)

Mydriasis

Impaired vision

Increased IOP (>20mmHg suspicious, >25mmHg= glaucoma)

Chronic: Optic disc cupping, Retinal degeneration, Buphthalmos, Physis bulbi

19

How is glaucoma classified and what are the causes? Are there breed predispositions?

Primary: most commonly caused by primary angle closure (goniodysgenesis); usually bilateral, common in Cocker Spaniels, Basset Hounds, Labradors

Secondaryassociated w/ other ocular or systemic abnormalites; most common cause= uveitits + hyphema, also neoplasia and lens luxation 

20

What are the most common medical therapies for glaucoma?

Latanoprost 0.005% - most effective for K9 primary glaucoma; increases uveoscleral outflow; use in an emergency as well as long-term

 

Dorzolamide 2% (Carbonic anhydrase inhibitors)- decreases aqueous production; emergency and long-term

IV Mannitol 20%: use when latanoprost and dorzolamide are ineffective

21

What are the surgical therapies for glaucoma? 

Gonioimpant- increase aqueous outflow

Ciliary body ablation/ Cyclodestruction- decrease aqueous production 

Would probably refer for these

 

22

What are the salvage procedures for blind and painful eyes?

Enucleation

Evisceration and prosthesis

Cilicary body ablation (intravitreal gentocin)

23

The optic nerve is extremely sensitive to increased IOP. With glaucoma the optic nerve will lose _____ and will be displaced _______, displaying a _____ appearance. 

Myelin

Posteriorly

Cupped

24

What is the only cause of buphthalmos? What is it?

Glaucoma

Enlargement of the globe

25

What are the fractures of Descemet's membrane called that occur secondary to buphthalmos and stretching of the globe, which can be seen as subtle white streals coursing across the cornea? 

Haab's Striae

26

What is gonidysgenesis?

Abnormal iridocorneal angle conformation in which the angle is narrowed or closed

27

What is the use of a goniolens, applied to the surface of the eye which allows light to bend into the iridocorneal angle and facilitates examination?

Gonioscopy

28

What are the 2 halmarks of glaucoma?

Increased IOP

Vision loss (from damage to the optic nerve and retina)

29

When measuring IOP with tonometry you obtain the values 25mmHg, 13mmHg, and 17mmHg. Which is the correct IOP?

13 mmHg (lowest IOP= most accurate)

30

T/F: Lack of pigment in the Retinal Pigmented Epithelium (RPE) is a normal variation of the fundus.

True

Common in blue-eyed dogs