- failure to execute learned purposeful movements e. g. inability to fixate in visual space

- Areas of blindness resulting from damage to V1 - Blind in corresponding contralateral visual field of both eyes

Vision Flashcards by Walker Short

What are the second order neurons in the retina?

Bipolar cell

How well did you know this?

Not at all

Perfectly

What is the third order neuron in the retina?

Retinal ganglion cells

How well did you know this?

Not at all

Perfectly

What do the retinal ganglion cells connect?

Retina to LGN

How well did you know this?

Not at all

Perfectly

What are the interneurons of the retina?

horizontal cells

- Amacrine cells

How well did you know this?

Not at all

Perfectly

What supplies blood to the photoreceptors?

Choroidal vasculature

How well did you know this?

Not at all

Perfectly

Are there any blood vessels in the fovea?

How well did you know this?

Not at all

Perfectly

In their normal state, are photoreceptors depolarized or hyperpolerized? Why?

Depolarized

-more open Na channels, increased Na conductivity

How well did you know this?

Not at all

Perfectly

What does light do to photoreceptor?

decrease cGMP
closes cGMP dependent Na channels
Cell hyperpolarizes, graded

How well did you know this?

Not at all

Perfectly

What is the main function of the retinal pigmented epithelium?

phagocytose the most apical outer segment discs of photoreceptors and recycle
Rods and cones produce about 100 new discs each every day

How well did you know this?

Not at all

Perfectly

What are the 5 functions of the Retinal pigmented epithelium?

Form the blood/PR barrier
Daily phagocytosis of outer segment discs
Vitamin A metabolism – reisomerize from trans back to cis
Melanin production to allow for high acuity
- High density of melanosomes and microvilli around cones – directional
- Low density of melanosomes and microvilli around rods – scatter
Neovascular barrier to prevent choroidal vasculature from entering the subretinal space

How well did you know this?

Not at all

Perfectly

Close to _____ ratio of cone to retinal ganglion cell at the fovea.

1:1

How well did you know this?

Not at all

Perfectly

Genes for long and middle wavelength opsins are tightly linked on the _____ chromosome.

How well did you know this?

Not at all

Perfectly

What does the dorsal stream process?

“Where”

How well did you know this?

Not at all

Perfectly

What does the ventral stream process?

“What”

How well did you know this?

Not at all

Perfectly

What is an agnosia?

-failure of recognition

How well did you know this?

Not at all

Perfectly

What is an apraxia?

failure to execute learned purposeful movements

e. g. inability to fixate in visual space

How well did you know this?

Not at all

Perfectly

What is a scotoma?

Areas of blindness resulting from damage to V1

- Blind in corresponding contralateral visual field of both eyes

How well did you know this?

Not at all

Perfectly

Which layer do neurons of the LGN input to in V1?

Layer 4 = simple cells

How well did you know this?

Not at all

Perfectly

Which layer of V1 are simple cells located?

Layer 4

How well did you know this?

Not at all

Perfectly

Which layer of V1 are complex cells located?

Layer 2/3

How well did you know this?

Not at all

Perfectly

Tonic Pupils = _____

sector iridoplegia (vermiform)

How well did you know this?

Not at all

Perfectly

What are versions?

-binocular movements in the same direction

=saccades & smooth pursuit

How well did you know this?

Not at all

Perfectly

What is supraversion?

Up gaze

How well did you know this?

Not at all

Perfectly

What is infraversion?

down gaze

How well did you know this?

Not at all

Perfectly

What is levotorsion?

When eyes rotate (wheel) tot he left

What are vergence eye movements?

- binocular, disconjugate eye movements | - convergence & divergence

What are vestibulo-ocular eye movements?

- reflexive | - compensate for change in head position (semicircular canals)

What is esotropia?

- inward eye deviation | - usually unilateral

What is exotropia?

outward eye deviation

What is hypertropia?

vertical eye deviation

What is the clinical term for double vision?

Diplopia

What is cranial nerve palsy vs paresis?

- Palsy: Complete paralysis of muscle innervated by a cranial nerve (can't get past midline) - Paresis: Incomplete paralysis of muscle innervated by a cranial nerve

Where is the origin of the inferior oblique?

anterior-medial orbit

What is Herring's law?

- law of parallel innervation - voluntary and involuntary eye movements - muscles are "yoked" and movements conjugate

What is Sherington's law?

- law of reciprocal innervation to extraocular muscles | - when agonist is activated, antagonist is suppressed

What is the leading cause of blindness in patients 20-64?

Diabetic Retinopathy

What is the pathogenesis of Non-proliferative diabetic retinopathy?

- vessels are abnormal - endothelial cells die - VEGF - random fragile vessels develop - these vessels burst

What is the pathogenesis of proliferative diabetic retinopathy?

- large tufts of vessels growing out of retina | - vitreous hemorrhage

Does diabetic retinopathy cause an afferent pupilary defect?

rarely

Does diabetic retinopathy cause scotomas?

- usually not | - may have relative scotoma in areas of severe edema or ischemia

How do we treat diabetic retinopathy?

1. blood sugar control 2. Blood pressure control 3. discussion with internist others: pan-retinal photocoagulation (PRP); VEGF inhibitor

What is the most common cause of central acuity loss in patients over 50?

Age related Macular degeneration (AMD)

What is the pathogenesis of age related macular degeneration (AMD)?

- Drusen accumulates between RPE & choroid - small round yellow lesions, contain lipids - product of lipid peroxidation - RPE can atrophy over time

Is there afferent pupilary defect in age related macular degeneration?

What may be an early finding in age related macular degeneration?

metamophopsia

What is the treatment for age related macular degeneration?

- vitamins (antioxidants and zinc) | - Injection of VEGF inhibitor

What is retinitis pigmentosa?

- genetic disease of rods - night blindness - progressive peripheral vision loss - genetic

What is the pathogenesis of retinitis pigmentosa?

-degeneration of rods, with secondary loss of RPE, and 3' loss of cones

Is there afferent pupilary defect with retinitis pigmentosa

What is the treatment for retinitis pigmentosa

none available

What is the pathogenesis of glaucoma?

- RGC axons die at optic nerve head - squeezed by lamina cribrosa * CUPPING

Is there afferent pupilary defect in glaucoma?

Not at first, will develop later

What is the treatment for glaucoma?

-lower intraocular pressure

What is central retinal artery occlusion (CRAO)?

-clot of central retinal artery

How does a patient present with a central artery occlusion?

- sudden, massive loss of vision - cherry red spot - big afferent pupilary defect

What are the possible treatments of central retinal artery occlusion?

- ocular massage - IOP reduction - tPA

What is a risk factor for central retinal artery occlusion?

-giant cell arteritis (GCA)

What is optic neuritis?

- sudden loss of vision in one eye, often central - pain with eye movments - massive afferent pupilary defect

What is the most common cause of optic neuritis?

What is the pathogenesis of optic neuritis?

MS: demyelination of ganglion cell axons in optic nerve Other: infiltration, inflammation, ischemia, infection

What is the treatment of optic neuritis?

- IV Steroids | - vision will return, often to baseline

Is there afferent pupilary defect in retinal detachment?

-no, unless massive and of long duration