Disorders Of Ocular Fundus

Question 1

What constitutes the ocular fundus

Answer 1

Retina - neuro sensory retina and RPE
Optic disc
Choroid - includes tapetum

Question 2

Spatial relationship of posterior eye structures

Answer 2

Neurosensory retina - clear and first structure
potential space between
RPE - retinal pigmented epithelium, can be non pigmented
Choriocapillaries
Tapetum -
Choroid
Sclera

Question 3

Tapetal features

Answer 3

Age/coat color can influence color
Size vary within species

Question 4

Tapetal reflectivity

Answer 4

Function of thickness of neurosensory retina /fluid underneath retina
Hyperreflectivity / hyporeflectivity

Question 5

blood vessels of fundus

Answer 5

Retinal vessel patterns vary in species
Choroidal vessels - vary in visibility, dependent on RPE pigmentation

Question 6

Holaniotic retinas

Answer 6

All of speices have this, vessels extend in all directs from disc to periphery of retina

Question 7

Optic disc

Answer 7

Normal appearance varies by species, degree of intraocular myelination

Question 8

Developmental disorders

Answer 8

Retinal dysplasia
Collie eye anomaly
Micropapilla
Optic nerve hypoplasia
Optic disc coloboma

Question 9

Retinal dysplasia

Answer 9

Anamolous retinal differentiation
Multi focal dysplasia - no clin sig
Geographic dysplaisa - can lead to retinal detachment
Total dysplasia - results in retinal detachment/non attachment

Question 10

Collie eye anomaly

Answer 10

Involves defects of posterior vascular (choroid) & fibrous tunics of eye
Highly pleiomorphic manifestations within litters

Question 11

Lesions of collie eye anomaly

Answer 11

Chorodial hypoplasia - sparse but enlarged choroidal vessels lateral to optic disc
Optic nerve & peripapillary coloboma - 2nd retinal detachment, 2nd hyphema

Question 12

Congenital small optic nerves

Answer 12

Micropapilla - small than normal optic nerve in visual eye, PLR normal
Optic nerve hypoplasia - smaller than normal optic nerve in BLIND eye, direct PLR in affected eye diminished to absent

Question 13

Optic nerve coloboma

Answer 13

Focal to extensive developmental defect of optic nerve - non progressive
Typical colobomas occur at 6 o clock position but may occur elsewhere
Vision impact is relative to coloboma size

Question 14

Optic neuritis findings

Answer 14

Ophthalmoscopic findings -
Intraocular optic neuritis - optic disc swollen, raised, hyperemia, papillary hemorrhage
Retrobulbar optic neuritis - fundus appears normal

Question 15

Retinal degenerative disorders

Answer 15

Progressive retinal atrophy (PRA)
Canine sudden acquired retinal degeneration syndrome (SARDS)
Feline central retinal degeneration (taurine deficiency retinopathy)

Question 16

Progressive retinal atrophy

Answer 16

Heritable, develops normally THEN degenerates
Rods degen first, then cones - dim light vision(NIGHT) impacted first
Age of onset/rate of disease progression variable - most progress to blindness

Question 17

DX of PRA

Answer 17

Signs can involve - diminished menace/PLR
Ophthalmoscopic abnormalities - tapetal hyperreflectivity, vascular attenuation, optic atrophy
*maze test, eleectroretinography

Question 18

Managing PRA

Answer 18

No effective treatment
Counsel owners regarding maintenance of safety
quality of life

Question 19

Canine sudden acquired retinal degeneration syndrome (SARDS)

Answer 19

Idiopathic disorder
sudden onset blindness, normal fundus
Small breeds, middle age, FS dogs
Concomitant polyphagia, weight gain, PU/PD
- Biochem panel abnormal: low urine SG, ^ SAP/ALT

Question 20

Feline central retinal degeneration (taurine deficiency retinopathy)

Answer 20

Taurine deficient diets causes retinal degeneration & dilated cardiomyopathy
Stages: start in area centralis —>extends in band dorsal to optic disc —>generalized disorder

Question 21

TX for FCRD

Answer 21

Normalize taurine intake to stop progression but will not reverse damage

Question 22

Mechanisms of retinal detachment

Answer 22

Exudative detachment - most common form, fluid build up under neurosensory retina
Rhegmatogenous detachment - due to tear in retina (periphery), vitreous fluid enters subretinal space & propagates tear
Traction detachment - rare in dom species

Question 23

Exudative detachment

Answer 23

Common cause: systemic hypertension, chorioretinitis due to infectious or immune mediated inflammation
Fix the cause = reattachment

Question 24

Rhegmatogenous detachment

Answer 24

Require surgical repair

Question 25

Chorioretinitis manifestations of systemic disease

Answer 25

Hypertensive retinopathy Chorioretinitis Optic neuritis

Question 26

Hypertensive retinopathy

Answer 26

Systemic hypertension - most common a secondary condition - kidney disease - hyperthyroidism - hyperadrenocoritcism - diabetes mellitus

Question 27

Complaints and findings with hypertensive retinopathy

Answer 27

Vision loss due to retinal detachment & hyphema Retinal arteriolar tortusity Retinal edema Retinal hemorrhage Retinal detachment

Question 28

Managing hypertensive retinopathy

Answer 28

Treat hypertension/disease Prognosis is generally good

Question 29

Chorioretinitis

Answer 29

Inflammation of choroid and retina Causes: Infectious, immune mediated, neoplastic, idiopathic

Question 30

Ophthalmoscopic findings for chorioretinitis

Answer 30

Inflammatory lesions are HYPOreflective Lesions may be focal, multi focal to coalescing or generalized Severe chorioretinitis leads to exudative retinal detachment

Question 31

DX chorioretinitis

Answer 31

Find underlying disease - work up TX /PX vary WIDELY