Optic Nerve Work-Up and Testing

Question 1

What is the most common optic neuropathy?

Answer 1

Glaucoma

Question 2

What type of disorders can patients experience photopsias?

Answer 2

retinal disease, optic nerve dysfunction, cerebral dysfunction from migraine and other disorders

Question 3

Why might past meds be important?

Answer 3

relevant to optic nerve disease
(amiodarone, ethambutol, tretinoin)

Question 4

Which medications are relevant to optic nerve disease?

ischemic, toxic and intracranial pressure

Answer 4

• Ischemic: amiodarone
• Toxic: ethambutol
• Intracranial pressure: vitamin A related compounds (tretinoin)

Question 5

Why is it important to cross reference meds and medical history?

Answer 5

Meds might reveal undisclosed medical conditions

Question 6

How can we formulate differential diagnoses?

Answer 6

localizing visual loss

Question 7

What does Ishihara test detect?

Answer 7

gross red-green only (designed for X-linked deficiencies)

Question 8

What does the Angel Anomaloscope detect?

Answer 8

sensitive R/G (there is a blue-yellow version now)

Question 9

What does HRR detect?

Answer 9

mild R/G or B/Y

Question 10

What does D-15 detect?

Answer 10

Gross R/G or B/Y

Question 11

What does FM-100 detect?

Answer 11

Sensitive R/G or B/Y

Question 12

What comprises the majority of acquired color vision deficiencies?

Answer 12

Tritan

Question 13

Congenital/ hereditary color deficiencies are almost ALWAYS which type?

Answer 13

red-green and males

Question 14

Where is the defect when a patient has reduced contrast sensitivity but normal acuity?

Answer 14

non-specific: may be media, retina, optic nerve

Question 15

Unilateral traumatic optic neuropathy does/does not cause an afferent pupillary defect?

Answer 15

does

Question 16

which eye do you place a neutral density filter over to grade an APD?

Answer 16

the “good eye”

Question 17

How do you perform the “Tilt Test”?

Answer 17

place 0.3 (50%) ND filter over the “bad eye”- should become a 1+ APD; place 0.3 (50%) ND filter over the “good” eye- should be NO APD

-penalizing the suspected bad eye should make the APD more obvious while putting it over the good eye should make it go away

Question 18

which visual field measurement can roughly correspond to APD grade?

Answer 18

mean deviation; a large difference in mean deviation should show a large APD

Question 19

Which pupil pathway starts at the outer retina?

Answer 19

afferent (rods and cones have input to intrinsically photosensitive ganglion cells)

Question 20

Where do the afferent pupil fibers synapse?

Answer 20

midbrain (NOT LGN)

Question 21

What 3 components contribute to the pupillary light reflex?

Answer 21

rods, cones and melanopsin

Question 22

What does melanopsin do?

Answer 22

causes a constriction that is maintained for many seconds after light offset

Melanopsin is relatively sensitive to shorter-wavelength light

Question 23

What are the two ways the optic disc responds to acquired pathologic processes?

Answer 23

swelling; pallor

Question 24

Edema/ Atrophy is a sign of an active disease process while Edema/Atrophy may be either active or old

Answer 24

Edema, Atrophy

Neither swelling nor pallor appearance alone give the diagnosis

Question 25

What are signs of true disc swelling?

Answer 25

Blurring of disc margin and small vessels

may have flame heme, CWS, hard exudates

Question 26

What is the cause of true optic disc swelling?

Answer 26

Obstruction of axonal transport at the lamina cribrosa

Question 27

What are late signs of disc swelling?

Answer 27

• gray or yellow atrophic appearance
• “Drusen like” hard exudates
• peripapillary retinal vasculature may be narrowed with a sheathed quality
• disc may no longer be capable of swelling even if there is a new insult

Question 28

What should you suspect if a patient presents with a hyperemic disk with flame-shaped hemes?

Answer 28

ischemia

especially if small cup and segmental (superior or inferior)

Question 29

What should you suspect if a patient presents with mild disc swelling without heme?

Answer 29

compressive/ infiltrative cause if subacute; inflammatory if acute and painful, toxic or matabolic if bilateral

Question 30

What should you suspect if a patient presents with pallid edema?

Answer 30

if acute: severe infarct of optic nerve

Question 31

Late-stage changes that occur in the optic nerve are a result of axonal degeneration in what pathway?

Answer 31

pathway between retina and LGN

visual function is disturbed. appearance of optic nerve head is changed

Question 32

What type of pallor occurs in Retinitis Pigmentosa and cone-rod dystrophy?

Answer 32

“waxy”

caused by glial proliferation

Question 33

What type of pallor occurs with macular conditions?

Answer 33

temporal disc pallor

not waxy

Question 34

what are 4 causes of cupping that are non-glaucomatous optic neuropathies?

Answer 34

• compressive lesions
• Ischemic (severe)
• toxic
• hereditary

non-glaucoma cupping usually has more pallor than cupping

Question 35

5 examples of optic neuropathy with disc swelling

Answer 35

1. papilledema
2. papillitis
3. compressive
4. NAION
5. AAION

Question 36

4 examples of optic neuropathy without disc swelling?

Answer 36

1. retrobulbar optic neuritis
2. PION
3. compresssive
4. toxic/nutritional