Retina and Optic Nerve Flashcards
Normal Variation
- Dogs
- Cats
Retinal Dysplasia
- who
- other causes?
• Usually inherited
– Can be associated with multiple ocular anomalies
• Other causes:
– Maternal viral infections
• Canine herpes and parvo viruses, feline panleukopenia
– Vitamin A deficiency
– X-ray irradiation
– Drug toxicities
– Intrauterine trauma
findings with retinal dystrophy
Retinal Dysplasia in Labrador Retrievers
Hereditary oculoskeletal dysplasia
Collie Eye Anomaly (CEA)
Inherited Retinopathies
- May initially affect rods, cones, or RPE
- Very long list of affected breeds
- Majority are autosomal recessive
retina and optic nerve (meekins)
Progressive Retinal Atrophy
• Clinical signs:
– Bilateral – progressive loss of vision–blindness
– Decreased night vision (nyctalopia) usually first sign
– Progressive decrease in PLR
– Larger than normal resting pupil size
• Owner will sometimes report increase in “eye shine”
– Cataract formation in very late stages
retina and optic nerve (meekins)
Sudden Acquired Retinal Degeneration Syndrome (SARDS)
- what
• SARDS-_acute_ photoreceptor death
• Usually middle aged to older dogs; female overrepresented
• All breeds affected
• Associated clinical signs
– May have ‘Cushing’s-like’ signs for weeks or months prior to vision loss
retina and optic nerve (meekins)
Sudden Acquired Retinal Degeneration Syndrome
• Clinical signs:
– Acute vision loss
– Variable PLR
• Chromatic PLR
• Red light –
• Blue light +
– Fundic exam
• NORMAL initially
• Chronic cases
– Retinal degeneration
retina and optic nerve (meekins)
Sudden Acquired Retinal Degeneration Syndrome
- Diagnosis:
- Treatment:
- Diagnosis:
- Electroretinogram (ERG)
- May have elevated ALP, or other Cushing’s-like changes on blood work; less commonly diagnosed with Cushing’s via traditional screening tests
- No proven treatment-permanent blindness
- Emphasize quality of life as blind pet
retina and optic nerve (meekins)
Retinal Detachments
small vs large
retina and optic nerve (meekins)
Rhegmatogenous retinal detachment
-
Retinal tear present which allows liquefied vitreous to enter subretinal
space - Primary ocular disorder (previous cataract surgery, inherited vitreal
degeneration, etc.)
retina and optic nerve (meekins)
Non-rhegmatogenous retinal detachment
- Remains attached at ora ciliaris retinae & optic disc
- Serous sub-retinal fluid-bullous retinal detachment
- Exudative retinal detachments-inflammatory or exudative sub-retinal fluid
- Systemic disease
retina and optic nerve (meekins)
Differentials for Non-rhegmatogeous RD
• Depends on type of sub-retinal fluid/material
• Exudate (cloudy or discolored, yellow)
– Same as chorioretinitis (i.e., posterior uveitis) → suspect systemic infection
• Transudate (clear)
– A.k.a. bullous
– *Hypertension
– Hypoproteinemia
– Idiopathic (steroid responsive?)
• Dog specific
retina and optic nerve (meekins)
Retinal Detachments
- always do ______ with non-rhegmatogenous patients
- Always perform a systemic work-up in animals with non-rhegmatogenous retinal detachments
– CBC/chemistry panel/urinalysis
– Blood pressure
– Chest radiographs
– Titers/antigen tests if any suspicion of infectious cause
retina and optic nerve (meekins)
Surgical Repair of Retinal Detachments
• Only appropriate for rhegmatogenous detachments
• Laser retinopexy
– 2 rows of burns around detachment to create adhesions
– Prophylactic vs. barrier
• Retinal reattachment
Retinal Hemorrhages: location
Retinal Hemorrhage
• Etiology
• Work-up
- Etiology
– Anemia
– Coagulopathy
– Systemic hypertension
– Hyperviscosity
– Systemic infections that cause vasculitis - Work-up
– Thorough physical exam!
– CBC (platelets!), chemistry panel, UA
– Blood pressure
– Clotting times
– BMBT
– Chest radiographs
– Titers/antigen testing if any suspicion of infectious cause
retina and optic nerve (meekins)
Optic Nerve Inflammation
- = Optic neuritis
- Unilateral or bilateral
- Can involve any segment of optic nerve (intraocular vs. retrobulbar)
- Associated with sudden blindness, fixed and dilated pupils
retina and optic nerve (meekins)
Optic Neuritis
retina and optic nerve (meekins)
DDX Optic Neuritis
retina and optic nerve (meekins)
Optic Neuritis Diagnostics
• CBC, chemistry panel, urinalysis
• Titers/antigen tests for infectious organisms
• Chest radiographs
• MRI or CT scan
• CSF tap
*Think of optic neuritis as a neurologic disease!*
retina and optic nerve (meekins)
Optic Neuritis Treatment
- Referral?
- Treat primary cause
- Systemic steroids (immunosuppressive dose)
- Oral antibiotics (empiric)
- Prognosis for vision = poor
retina and optic nerve (meekins)
Summary
- 3 hallmark signs of retinal degeneration:
- SARDS results in…
- Rhegmatogenous retinal detachments are due to…
- Non-rhegmatogenous retinal detachments are due to…
- Optic neuritis is…
- 3 hallmark signs of retinal degeneration:
- *– Tapetal hyperreflectivity**
- *– Retinal vessel attenuation**
- *– Optic disc pallor**
- SARDS results in sudden blindness with a normal ophthalmic exam (ERG needed to definitively diagnose)
- Rhegmatogenous retinal detachments are due to primary ocular disease
- Non-rhegmatogenous retinal detachments are due to systemic disease
- Optic neuritis is a neurologic disease!
