optho 3

Question 1

Answer 1

iris atrophy- senile loss of iris tissue, thinning of stroma
moth eaten pupillary margin
scalloped appearance

can cause PLR deficit

Question 2

Answer 2

uveal cyst, b/w cornea and iris
benign, common in goldens and labs
no tx unless interfering w vision-> laser, aspirate

Question 3

Answer 3

hyphema- blood in anterior chamber
if excessive-> globe rupture

Question 4

hyphema causes

Answer 4

trauma, tumour, retinal detachment, anterior uveitis

systemic- clotting disorder, leukemia, hypertension

Question 5

Answer 5

feline diffuse iris melanoma- most common
no destruction of iris, can become malignant, developing anterior uveitis, glaucoma, vision loss

Question 6

high risk iris melanoma patients:

Answer 6

> 50% iris area, elevation, pigment in anterior chamber
dyscoria
glaucoma

Question 7

FIDM tx

Answer 7

monitor for changes in IOP
laser early
enucleate if glaucoma

Question 8

aqueous humour dynamics

Answer 8

produced in ciliary body-> maintains normal ocular pressure

flows into posterior chamber-> pupil-> anterior chamber-> ICA

Question 9

glaucoma causes (primary and secondary)

Answer 9

primary: goniodysgenesis->continuous tissue sheet across ICA, normal pectinate ligament dont form.
glaucoma occurs w aging

congenital form- rare

secondary:
anterior lens luxation, uveitis, neoplasia, hyphema, retinal detachment

Question 10

glaucoma pathogenesis, effects of increased IOP

Answer 10

destroys ganglion cells and optic nerve
1. ischemic damage
2. compression of axons
3. later degeneration (optic nerve cupping, lamina cribosa-> irreversible)
4. injected vessels
5. mydriasis
6. corneal edema
7. bupthalmia
8. haabs striae
9. lens subluxation (posterior)
10. pain

Question 11

glaucoma tx

Answer 11

establish vision- dazzle, menace
chronicity
emergency tx-> beta blocker (timolol), carbonic anhydrase inhibitor (trusopt) to decrease AH production
increase outflow->lantanaprost

surgery: laser cyclophotocoagulation- damages ciliary body to decrease fluid production

gonioimplant- drainage implant

Question 12

chronic glaucoma tx

Answer 12

if vision is not restored-> comfort
keep IOP <35

enucleation w implant
evisceration (can get dry eye)
intravitreal gentamicin-> damages ability to produce aqueous

Question 13

cataract types

Answer 13

lens opacity, classified based on stage
incipient- sm focal opacity
immature- diffuse, still have tapetal reflex, can see fundus so no surgery
mature- no fundic reflex
hypermature- lens liquifies-> anterior uveitis

Question 14

cataract causes

Answer 14

diabetes (50% within 5-6m, 80% in 16m)-> sorbitol pathway creates osmotic gradient
genetic, age, uveitis (cats). nutrition

Question 15

cataract tx

Answer 15

surgery- phacoemulsification

Question 16

Answer 16

nuclear sclerosis- hardening of lens w age (7y), not opaque

Question 17

Answer 17

anterior lens luxation- dislocation

Question 18

Answer 18

lens subluxation w aphakic crescent
vitreous in anterior chamber

Question 19

iridogenesis, phacodonesis

Answer 19

trembling of iris w eye movement
trembling of lens w eye movement

Question 20

lens luxation causes (primary and secondary)

Answer 20

primary- genetic
secondary- glaucoma, chronic uveitis, trauma, age

Question 21

lens luxation and glaucoma

Answer 21

primary luxation (anterior)-> glaucoma

glaucoma-> luxation (posterior)

Question 22

lens luxation tx

Answer 22

subluxation- meds to induce miosis, lantanaprost
posterior- induce miosis
primary anterior- remove lens

Question 23

Answer 23

asteroid hyalosis- calcium/cholesterol

Question 24

Answer 24

progressive retinal atrophy
(hyper reflectivity, vessel attenuation)
inherited photoreceptor disorder-> slow progressive vision loss, night blindness

Question 25

syneresis

Answer 25

liquefaction of vitreous (swriling material)- aging change

Question 26

sudden acquired retinal degeneration

Answer 26

sudden blindness where retinas appear normal
poor PLRs
cause unknown, no tx

Question 27

Answer 27

chorioretinitis- hazy border to lesions
inflammation, can cause detatchment
caused by systemic disease

Question 28

Answer 28

chorioretinal scar
lesions arent raised, have clear borders, vessels look normal.

Question 29

Answer 29

bullous retinal detatchment- entire retina peels off due to accumulation of inflammation, hemorrhage
(chorioretinitis, hypertension)

Question 30

Answer 30

rhegmatogenous retinal detatchment- caused by tear (hypermature cataract, trauma)

Question 31

Answer 31

optic neuritis- acute to subacute blindness
causes: idiopathic, immune, neoplasia, lymphoma, infectious
dx- ophthamloscopy, ERG, MRI, CSF tap

tx- steroids, depends on cause