4 - Decreased Vision Classification and Management Flashcards
1
Q
Decreased vision from K or lens abnormalities may show what?
A
Generalized reduction of sensitivity on automated perimetry testing
2
Q
Maculopathy characteristics
A
- No APD unless extensive retinal abnormality
- Parallel loss of color and VA unlike optic neuropathy EXCEPT in cone dystrophy where patients have severe color impairment without decreased VA
- VF Defects focal and central (macula) unlike optic neuropathies where VF defect larger, cecocentral (from blind spot at optic nerve temporally to fixation centrally) and associated with generalized depression of visual field sensitivity
- Metamorphopsia
- OCT, autofluorscence, FA used
- Maculopathies and retinopathies with normal DFE findings may be mistaken for optic nerve disease → AIBSE, AZOOR, MEWDS, cone dystrophy
- May show mild ONH pallor in chronic retinopathies
3
Q
AIBSE/AZOOR/MEWDS
A
- AIBSE → prominent visual symptom monocular scotoma temporal in location associated with photopsias. Main findings is enlarged blind spot. DFE may be normal, or show ONH edema, peripapillary retinal lesions, choroiditis, uveitis, RPE changes
- AZOOR → similar to AIBSE + more extensive retinal changes
- MEWDS → DFE may show small deep retinal white spots lasting for several weeks and resolve spontaneously or normal DFE, photopsias prominent symptom reflecting outer retinal disease
- FA, ICG abnormal
- All diseases may show small APD
4
Q
Cone Dystrophy
A
- Characterized by gradually progressive decline in visual acuity and color vision that may be mistaken as bilateral optic neuropathy
- Photophobia and hemeralopia (day blindness) common
- DFE may be normal or show slightly blunted foveal reflex with granular macular pigmentation, as disease progresses macular RPE becomes atrophic in central oval region (bull’s eye)
- OCT thinning of outer layers, loss of EZ zone, multifocal ERG with central depression
5
Q
CAR
A
- Bilateral progressive vision loss and decreased color vision that may be asymmetric in onset
- Associated with photopsias, nyctalopia, ring scotoma, peripheral/central visual field loss, impaired dark adaption
- Small cell lung carcinoma most common
- DFE may be normal but ERG with decreased amplitudes
- As disease progresses, arterioles attenuated, RPE thinned, ONH atrophic
- Vision loss typically severe
- Recoverin antibodies only + in minority of patients
- If clinical suspicion high → look for underlying cancer
6
Q
MAR
A
- Mostly affects Rod cells.
- Associated with photopsias, nyctalopia, prominent peripheral visual field loss
- Rapidly develops weeks to months or sudden onset
- Usually patient with previous melanoma
- Antibody to TRPM1 cation channel may be seen
- DFE normal or with RPE irregularity, arterial attenuation, ONH pallor
- Full-field ERG with rod dysfunction; multifocal ERG measures photopic responses of cones thus normal
- Visual function may remain stable and nonprogressive
- No Tx
7
Q
Autoimmune retinopathy nonparaneoplastic
A
- Variable presentation diagnosis of exclusion
- 50% associated with autoimmune disease
- Usually cone-system dysfunction
8
Q
Optic Neuropathy
A
- VA decreased, VF loss, dyschromatopsia, RAPD
- ONH may be normal, acutely swollen
- Optic atrophy (pallor) takes 4-6 weeks to develop even after vision has recovered
- VF defects from
- papillomacular fibers
- arcuate fibers
- nasal radiating fibers
9
Q
Papillomacular Fiber Scotomas
A
- Cecocentral → ON (blind spot) to fovea (fixation)
- Paracentral → Next to and around fixation
- Cental → fixation
10
Q
Paracentral Scotoma
A
11
Q
Pericentral Scotoma
A
Involves region symmetrically surrounding fixation
12
Q
Arcuate Fibers
A
- Arcuate scotoma → nerve fiber bundle defect
- Altitudinal defect → broader region of arcuate fibers involving 2 quadrants
- Nasal step → temporal portion of arcuate fibers
All fibers along temporal horizontal raphe thus damage produces defects that respect nasal horizontal meridian
13
Q
Arcuate Scotoma
A
14
Q
Altitudinal Defect
A
15
Q
Nasal Step
A
16
Q
Nasal Radiating Fibers
A
Temporal wedge defect from damage to nasal radiating fibers
17
Q
Nasal Retina?
A
- Papillomacular fibers (nasal to fixation) + Nasal radiating fibers (nasal to blind spot)
18
Q
Absolute Vs. Relative Scotoma
A
19
Q
Optic Neuropathy Causes
A
20
Q
Papilledema
A
- ONH edema + elevated ICP
- Acute papilledema → hyperemia of ONH, dilation of ONH capillary net, telangiectasia of radial peripapillary vessels, edematous peripapillary RNFL grayish white and opalescent with feathered, striated margins that obscure ONH edge and retinal vessels
- Must rule out pseudopapilledema 1st step → hyperemia, flame hemorrhages, telangiectasia, opacification of peripapillary RNFL suggest true ONH edema. Most causes of pseudopapilledema DO NOT cause obscuration of vessels
- Most cases of pseudopapilledema result from ONH drusen
- Hyaloid remnants and glial tissue on ONH surface
- Small scleral canal creating fullness of ONH from entry of ON
- ONH fullness associated with hyperopia
- Vitreopapillary traction
- Myelinated nerve fiber layer → when contiguous may be mistaken for ONH edema or CWS
21
Q
Stages of Papilledema
A
- Starts inferior and superior poles → nasal ONH creating a C-shaped area of ONH edema sparing temporal rim
- Halo becomes circumferential and blurs vessels off ONH
- Loss of major vessels on ONH and absence of cup
22
Q
Papilledema ophthalmoscope findings
A
- Absence of SVPs may reflect ICP → 20% gen population no SVPs but important to document
- ONH and peripapillary CWS, exudates, hemorrhage
23
Q
Papilledema symptoms
A
- HA, nausea, vomiting, TVOs (uni/bilateral lasting seconds) → grayouts, whiteouts, blackouts with orthostatic changes
- Early papilledema → ON function & VA and Colors normal, pupils normal. VF may show enlargement of blind spot
24
Q
Myelinated nerve fiber layer
A
25
Papilledema Causes
1. Mass
2. Hydrocephalus
3. Infection, granulomatous infiltration, neoplastic process
4. IIH
5. Cerebral Venous thrombosis or dural fistula causing increased venous pressure
Suspicion of papilledema → MRI, MRV brain and orbits with contrast. Normal brain imaging → CSF opening pressure and evaluation via LP
26
Chronic Papilledema
27
Chronic Papilledema
1. Refractile bodies → pseudodrusen aka and believed to be extruded from ONH
28
Optociliary Shunt Vessels
1. Old CRVO
2. Meningioma
3. Low-grade Glioma
4. Chronic Glaucoma
29
IIH
1. Present with symptoms and signs of elevated ICP
2. HA, neck and back pain, TVOs, diplopia 2/2 CN6, pulsatile tinnitus, nausea
3. Papilledema usually seen
4. Early IIH → normal VA, enlarged blind spot
5. 90% women and obese
6. Exogenous Vit A (\>100k IU/day), tetracycline, minocycline, doxycycline, retinoic acid, lithium, steroid use, steroid withdrawal, sleep apnea, pregnancy, anemia
7. Unknown cause of elevated ICP
30
IIH - Venous Etiology
1. OCP, pregnancy, hypercoagulable states, lupus, infection (middle/inner ear infections), dehydration, acute head injury
31
Empty Sella MRI
32
IIH Follow-Up
1. Long-term follow-up essential
2. Test VA, color vision, perimetry, ONH photograph
3. Frequency of VF testing depends on severity of papilledema, ON dysfunction, patient's response to treatment
33
IIH Treatment
1. Depends on symptoms and vision status
2. May be self-limited
3. Mild HA and no ON dysfunction → No tx
4. Untreated papilledema → severe vision loss in 5-10% of people
5. Poor vision loss → Males, AA, obesity, severe papilledema, anemia, RAPD, abnormal VF testing, fulminant course
6. Weight loss can be effective → nutritionist referral may be helpful
7. Medical therapy
1. Acetazolamide 1-4g/day
2. Topiramate → May help chronic headaches, appetite suppression, Carbonic anhydrase inhibition
3. Furosemide → cannot tolerate acetazolamide and topiramate
4. Avoid Steroids but may be used for short course for fulminant IIH
5. Avoid repeat LPs
8. Surgical therapy → substantial vision loss despite max tolerated medical therapy
1. ONSF, LP shunt, VP shunt
2. ONSF → in those w/out HA, often preferred because protects ON and lower morbidity than shunting. ONSF does not lower ICP significantly thus does not reliably treat HA. 10-15% complication rate
3. LP/VP → lower ICP and improve HA, CN6 palsy, papilledema, no risk to ON, but may become occluded, infected, altered in position
Many patients will have chronic headaches despite effective treatment and improvement of papilledema → usually HA not related to elevated ICP and should be managed medically with neurologist
34
Isolated Optic Neuritis - Atypical features
1. Atypical features
1. Older age
2. Lack of pain
3. Persistent pain or vision loss
4. **Significant ONH swelling with peripapillary hemorrhages or exudates**
5. Ocular inflammation
6. Vision loss
7. Retinal changes
8. CN palsies
9. steroid responsive ON
10. Lack of recovery by 1 month
2. Note → atypical features especially significant ONH swelling + peripapillary hemorrhages or exudates associated with lower risk of future MS
35
Atypical ON Work-up
36
Isolated Optic Neuritis Course
1. ONTT → 10 yr follow-up recurrence in either eye in 35% cases, 45% patients converted to MS
2. ONTT → 15 yr follow-up 92% patients recovered VA 20/40 or better, 3% VA 20/200 or worse
3. ONTT → 15 yr data found risk of MS 25% for patients with no lesions on MRI Vs. 72% for patients with at least 1 lesion Vs. 2% for patients with normal MRI. Highest rate of conversion within first 5 years
4. Despite excellent prognosis → patients remain aware of VF defects
5. Residual abnormalities in 90% patients → color VA, contrast, motion detection, stereopsis, perimetry
6. In absence of known MS → MRI brain should be performed
37
Isolated Optic Neuritis Treatment
38
CRION
39
NMO/NMOSD
1. Optic neuritis + acute myelitis within weeks or months of each other or several years
2. Visual prognosis poorer than MS
3. More recurrence and more severe \<20/200 in at least 1 eye
4. AQP4-IgG testing → severe vision loss, bilateral optic neuritis, recurrent optic neuritis, extensive enhancement on ON on MRI, irreversible vision loss after 1 month
5. Treatement
1. Acute → IV steroids
2. Plasmapheresis for poorly responsive NMO, IVIG
3. Azathioprine, rituximab can reduce risk of relapse
40
Neuroretinitis
41
Optic Perineuritis
1. Peripheral Vision Loss \> Central Vision Loss
42
Anterior Ischemic Optic Neuropathy
43
AAION
44
NAION
45
NAION
46
PION
1. Due to hypoperfusion of nerve
2. Rarely → vasculitic process
47
Perioperative Optic Neuropathy
48
Diabetic Papillopathy
1. FA shows leakage at disc but NOT into vitreous (NVD leaks into vitreous)
2. See enlargement of blind spot → NO other VF defects evident. If other defects seen then consider other etiologies
49
Papillophlebitis
50
Toxic/Nutritional Optic Neuropathy
1. **Gradual, progressive, painless vision loss that is bilateral and symmetric**
2. As becomes more severe → central vision loss worsens and central scotoma develops; **usually papillomacular bundle affected and thus may see temporal nerve pallor**
3. Rarely ONH edema
4. Causation usually multifactorial
5. Methanol (rapid with ONH edema), ethylene glycol (rapid with ONH edema), lead, tobacco, ethambutol (bitemporal pattern of VF loss as decussated RGC axons in chiasm more susceptible to damage), linezolid, amiodarone (bilateral with diffuse ONH edema, subacute onset), disulfiram, ciprofloxacin, cisplatin, vincristine, ethanol (causes malnutrition), anti-TNF alpha (also may cause demyelinating optic neuritis) → etanercept, infliximab, adalimumab
6. Deficiency → Vit B12, copper, folate, thiamine
7. DDX → maculopathies, compressive, demyelinating, infiltrative, hereditary → need FA, serologies, CSF analysis, and need neuroimaging to rule out compressive etiology
51
LGN VF defects?
1. Homonymous sectoranopia
