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Neurology > Opthamology > Flashcards

Opthamology Flashcards

1
Q

Pupil basics

A

Is a hole in the middle of the iris and is made up of the circular muscles and radial muscles

  • circular = pupillary sphincter
  • radial = pupillary dilator
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2
Q

What controls the circular and radial muscle contractions?

A

Circular (constriction of pupil)

  • parasympathetic response
  • occurs in bright light
  • occurs when calm/relaxed
  • occurs when high on opioids

Radial (dilation of pupil)

  • sympathetic response
  • occurs in dim light
  • occurs when afraid
  • occurs when high on cocaine/ amphetamines
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3
Q

What is anisocoria

A

Unequal pupils

in bright light:
- the larger pupil = loss of parasympathetics ipsilaterally

In dim light:
- the smaller pupil = loss of sympathetics ipsilaterally

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4
Q

What tumor is most common in causing horners syndrome?

A

Pancoast tumors

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5
Q

Anatomy of the sympathetics for the eyes

A

First order = hypothalamus
- runs down the brainstem and into spinal cord where it synapses at C8-T2

Second order = exits out C8-T2 and goes to the inferior cervical ganglion
- ruins over the apex of the lung around the subclavian artery and synapses on the superior cervical ganglion

Third order = exits off superior cervical ganglion and ascends along the carotid artery
- runs through cavernous sinus and innervates muscles via CN3 tract

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6
Q

Most common causes of ipsilateral Horner syndrome in ophthalmology

A

Brainstem stroke (usually medullary syndrome)

Cord hemisection (brown-sequard syndrome)

Pancoast tumors at apex of lung

Carotid artery dissections

Damage at the cavernous sinus

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7
Q

Anatomy of parasympatheticsof the eye

A

Afferent:
- Light signals are received through CN 2 and travels along the nerve

  • Hemi-decussates at optic chiasm
  • Synapses onto E-W nuclei bilaterally in the rostral midbrain near the superior colliculi

Efferent:
- travels along CN 3 from E-W nucleus

  • synapses in the ciliary ganglion and runs along short ciliary nerves to innervate the iris sphincter
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8
Q

What is the most sinister etiology for a blown pupil?

A

3rd nerve palsy
- caused by aneurysm of the circle of wills or herniation of the uncus impinging on the CN 3

Classic clinical signs are

  • ptosis
  • mydriasis
  • eye is down and out
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9
Q

Relative afferent pupillary defect (RAPD)

A

Results from a lesion in the CN2 nerve or some sort of damage.
- the pupils are always the same size but respond differently to light
(I.e shining light in the left eye = 100% constriction in both. Shining light in the right eye = 50% constriction in both)

Common causes are optic neuritis, MS, retinal artery occlusions

can cause red color dislocation (where red looks like orange)

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10
Q

What is a quick and easy way to differentiate 3rd nerve palsy from chemical mydriasis?

A

Use 1% pilocarpine eye drops on the dilated pupil.

  • if it DOES NOT constrict = NOT 3rd nerve palsy
  • if it DOES constrict = 3rd nerve palsy
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11
Q

What does a blurred optic disc signify?

A

A blockage of the axoplasmic flow from the optic nerve

Causes:

  • ischemia to the nerve
  • high cranium pressure
  • optic neuritis
  • metabolic dysfunctions (toxic ODs, hereditary mitochondrial diseases
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12
Q

what is OD vs OS abbreviations mean?

A

OD = right eye

OS = left eye

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13
Q

Papilledema

A

Swelling of the optic nerve at the retina which causes a swollen blurry optic disc which is CAUSED BY INCREASED INTRACRANIAL PRESSURE

if it is not caused by increased intracranial pressure, it is an “optic nerve disease” not papilledema

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14
Q

Idiopathic intracranial hypertension (IIH)

also known as Pseudotumor cerebri

A

Classic risk factors:

  • use of tetracyclines
  • over use of vitamin A
  • obesity (especially rapid and recently)

Classic signs:

  • transient visual obscurations
  • pulsation tinnitus
  • occasional horizontal diplopia

Diagnosis:

  • increased CSF pressure > 25mmHg
  • NO ABNORMALITIES IN CSF counts
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15
Q

What is a classic MRI sign for MS?

A

Bright finger-like projections of brain tissue that are just superior to the corpus callosum in the sagittal view.

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16
Q

Optic neuritis

A

More common in ages 20-40s

Very common with MS patients

Classic signs:

  • pain in the eye that is losing vision
  • eye movement causes pain in the eye
  • red colors are less saturation (dissociation)
  • requires brain and orbit MRI/CT to confirm*
17
Q

When should your never LP a patient with papilledema or blurred optic disc?

A

If you have not ruled out a tumor yet.

if a tumor is present, LP will cause herniation of brain tissue to the medulla and impinge on it, causing respiratory and cardiac failure

18
Q

Bitemporal hemianopia

A

Caused by lesion to the optic chiasm in sagittal fashion
- knocks out the lateral aspects of both eyes

common in pituitary tumors

19
Q

Where does the fibers of the optic tract travel to?

A

The lateral geniculate ganglion (LGG) of the thalamus
- from here it becomes optic radiations and splits into an upper (parietal) and lower (temporal) pathways

The radiations travel directly to the visual cortex in the occipital lobe

20
Q

Upper quadrantanopia

A

Damage to the lower (temporal part) of the optic radiations

Causes upper 1/4 visual blindness in either the right side of both eyes (left optic radiations) or the left side of both eyes (right optic radiations)

21
Q

Lower quadrantanopia

A

Damage to the upper (parietal part) of the optic radiations

Causes lower 1/4 visual blindness in either the right side of both eyes (left optic radiations) or the left side of both eyes (right optic radiations)

22
Q

What does damage tot he occipital lobe itself cause?

A

Causes similar defects to optic tract lesions

- mild subtly different though, but not important to know now

23
Q

What is the general rule for visual fields?

A

Everything is flipped

24
Q

Dorsal stream dysfunction

A

The “where” stream

Causes the following:
- stimultanagnosia: cant pay attention to more than one object at a time

  • astereognosis: inability to perceive the depth perception of objects
  • akinetopsia: inability to detect motion
25
Q

Ventral stream dysfunction

A

The “what” stream

Causes the following:

  • achromatopsia: cant see colors
  • caused by bilateral lesions of the fusiform and lingual gyri
  • prosopagnosia: cant recognize faces
  • caused by bilateral/ right sided fusiform and anterior temporal lobe lesions
  • topographagnosia: cant orient oneself to there surroundings
  • caused by parahippocampal lesion
26
Q

What is the inner layer of endothelium in the cornea responsible for?

A

Keep a dehydrated state of the cornea (keeps it clear)

- will turn opaque and cloudy if knocked out

27
Q

What are the steps of a basic eye exam?

A

1) measure and record visual acuity
- if the vision is blurry naturally, use pinhole glasses

2) examine the pupillary responses
- afferent pupillary defect
- assess pupil shape/size and symmetry

3) examine ocular motility (pressure)
- range and symmetry of 9 cardinal positions of gaze
- assess the corneal light reflex or the cover/uncover technique

4) assess visual fields
5) assess palpation of the orbit globe (if not a trauma)
6) examine the important structures of the anterior segment of the eye with a penlight
7) examine the fundus with either a direct ophthalmoscope or fundus photography

28
Q

Retinal detachments

A

Signs/symptoms

  • often preceded by flashing lights/floaters in vision
  • presents commonly as a “curtain encroaching towards central vision”
  • typically sudden onset
  • commonly occurs via trauma of posterior vitreous detachments
  • many times does not show other clinical findings

*this is urgent and needs to be referred to dilated eye exam

29
Q

What are the three main retinal vascular events?

A

Retinal arterial occlusion
- “cherry red macula”

Retinal vein occlusion

Amaurosis fugax

30
Q

Amaurosis fugax

A

Signs and symptoms:

  • very Broad often includes migraine, dry eyes, TIA, MS and elevated intraocular pressure
  • there are not ocular findings during exams
  • “curtain coming over my vision”
  • this is worry some since it can cause a stroke
  • monocular vision loss = carotid artery issues
  • binocular vision loss = vertebral/basilar artery issues
31
Q

What are common risk factors for cataracts?

A

Diabetes

Smoking

Elderly

32
Q

When should you refer a red painful eye out to an ophthalmologist (be worried)?

A

STOP

Sudden visual loss/change
Trauma
Other signs/symptoms in conjunction
Pain (deep pain only)

  • if not one of these 4 categories, is usually non-urgent*
33
Q

Preseptal cellulitis

A

Urgent issue

Symptoms:

  • red painful eye
  • pain is increased with eye movement
  • decreased overall vision
  • fever and chills are present

treatment:
- gram positive antibiotics topical or oral

34
Q

Corneal abrasion

A

Urgent issue

Symptoms:

  • red painful eye
  • often caused by trauma
  • no foreign body present

Treatment:

  • topical antibiotics
  • DONT USE STEROIDS
35
Q

What bacteria must always be considered in contact lens patients that present with red and painful eye?

A

Pseudomonas

36
Q

What are the three main types of eye trauma?

A

Blunt

Penetrating

Perforating

  • type 6 most common ocular trauma causes*
    1) corneal abrasions
    2) corneal foreign bodies
    3) corneal or scleral lacerations
    4) ruptured globe
    5) hyphema
    6) chemical injury
37
Q

Difference between alkaline and acid chemical injuries to the eye

A

Acid:

  • more painful
  • less chance of penetrating

Basic:

  • less painful
  • more chance of penetrating
  • both need to start with irrigating the eye and getting within optimal pH range*
38
Q

What is the classic triad of symptoms for congenital glaucoma?

A

Photophobia

Epiphora (over production fo tears when not crying)

Blepharospasm (eyelid spasms)

Neurology (65 decks)

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