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3C week 1- intro to neuro and opthal > fundamentals of ophthalmology > Flashcards

fundamentals of ophthalmology Flashcards

1
Q

7 questions to ask if pt presents with red eyee

A
  1. both eyes or just one
  2. discharge
  3. pain
  4. lacrimation
  5. blurred vision
  6. photophobia
  7. associated symptoms
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2
Q

what cells carry information from the rods/cones to the brain

A

retinal ganglion cells (concert light energy into electrical)

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3
Q

what test is used for visual acuity

A

snelling chart (distance chart is read from/distance a person with normal vision could read the line from

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4
Q

what is myopia

A

Nearsightedness (objects nearby are clear) - when the distance between the cornea and retina is too long and so the image is focused in front of the retina

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5
Q

what can be used to correct myopia

A

concave lenses

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6
Q

what is hyperopia

A

farsightedness (far object clear) - the distance between the cornea and retina is too short so the image is focused behind the retina

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7
Q

how is hyperopia corrected

A

convex lenses

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8
Q

what is the pinhole effect

A

an optical concept suggesting that the smaller the pupil size, the less defocus from spherical aberrations is present (i.e. the image is clearer the smaller the pupil size)

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9
Q

what can be used to test colour vision

A

ishihara colour plates (or red desaturation test if not available)

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10
Q

what is the most common symptom of optic nueropathy

A

R/G colourblindness

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11
Q

what is optic neuropathy

A

damage to the optic nerve

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12
Q

a lesion where causes Homonymous hemianopsia with macular sparring and how does the macular sparing occur

A

occipital lobe

the macular region is of high importance and so is supplied by both the PCA and the MCA, meaning that if there is a blockage in one of these arteries, the macular area can still receive blood from the other artery and therefor still function

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13
Q

what will a lesion in the optic nerve cause

A

complete vision loss in one eye only

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14
Q

what will a lesion in the optic chiasm cause

A

bitemporal hemianopsia (chiasm is where the fibres cross over - right side of each eye supplies the right side of the brain so the fibres coming from the left eye need to cross in the chiasm and vice versa)

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15
Q

what does a lesion in the optic tract cause

A

Homonymous hemianopia

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16
Q

what does a lesion in the optic radiations cause

A

homonymous quadrantinopia

17
Q

what does a lesion in the occipital lobe (striate cortex) causw

A

Homonymous hemianopsia with macular sparing

18
Q

pathway of vision (eye -> visual cortex)

A

eye -> optic nerve (via retinal ganglion cells) -> optic chiasm -> optic tract -> LGN ->optic radiations -> striate cortex (V1)

19
Q

what 4 muscles does CN III innervate

A

superior rectus; medial rectus; inferior rectus; inferior oblique

20
Q

what muscle does CN IV innervate

A

superior oblique

21
Q

what muscle does CN VI innervate

A

lateral rectus

22
Q

if one pupil constricts what happens to the other

A

it constricts - what happens to one always happens to the other

23
Q

what is the relative afferent pupillary defect (RAPD)

A

a condition in which pupils respond differently to light stimuli shone in one eye at a time due to unilateral or asymmetrical disease of the retina or optic nerve

24
Q

what happens in RAPD

A

if there is a lesion in the optic nerve on one side, then when a torch is swung between the two eyes, dilation is seen as it is swung to the affected eye as the brain is registering lower light levels (than when the torch was shone on the unaffected eye) due to the disturbance in the nerve not transmitting the same intensity of light ass the unaffected eye did

25
Q

what is anisocoria

A

difference between the pupil sizes

aniso-” meaning unequal, “kore” meaning pupil

26
Q

what is Adie’s tonic pupil (aka Adie’s Syndrome or Holmes-Adie Syndrome)

A

parasympethetic denervation of the afflicted pupil; typically initially appears abnormally dilated at rest and has poor or sluggish pupillary constriction in bright light; tendon reflexes may also be slow (holmes-adie syndrome)

27
Q

what is denervation hypersnistivity

A

the sharp increase of sensitivity of postsynaptic membranes to a chemical transmitter after denervation - the post synaptic receptors are upregulated in attempt to compensate for the lack of innervation

28
Q

what pharmacological test can be used to test for adie’s syndrome

A

0.125% pilocarpine - abnormal pupil will constrict while normal will not, the affected pupil is supersensitive to Ach and so will constrict while the normal will not

29
Q

how might Adie’s syndrome occur

A

Damage to the parasympathetic ciliary ganglion may result in a tonic pupil - The parasympathetic fibers of the eye travel with the third cranial nerve to synapse at the ciliary ganglion before innervating the iris and the ciliary body

may be due to hepatic infection

30
Q

adie’s syndrome pathopsy

A

damage to the ciliary ganglion occurs -> denervation hypersensitivity (postsynaptic receptors are upregulated to facilitate reinnervation) -> fibers intended for the ciliary body may end up targeted to the pupil ( aberrant regeneration) -> patients develop Light-Near dissociation of the pupil by which the near accommodation produces more miosis compared to response to light, the reaction which is tonic

31
Q

horner’s syndrome symptoms (5)

A

P- ptosis
A- anhydrosis
M - miosis
E - enophthalomos (sunken eye due to loss of sympathetic tone)
L - loss of ciliospinal reflex
a

32
Q

in pre-ganglionic horner’s syndrome, what happens to the pupil when hydroxyamphetamine is given (causes sympathetic stimulation)

A

both pupils dilate - NA is still present in the post ganglionic neurons and so this can cause depol and the pupil can dilate

33
Q

in post-ganglionic horner’s syndrome, what happens to the pupil when hydroxyamphetamine is given (causes sympathetic stimulation)

A

NA release to the effector muscle is blocked so the pupil does not dilate

34
Q

in post-ganglionic horner’s syndrome, what happens to the pupil when 1:1000 adrenaline is given (very small dose)

A

affect pupil will dilate due to hypersenitivity denervation in the affected eye meaning that a small amount will have a big effect

35
Q

what are the 3 Cs to look for in fundoscopy

A
  1. colour
  2. contour
  3. cup to disc ratio
36
Q

what are the features of the optic nerve that make it easierto identify

A

well demarcated circular area where all the blood vessels converge

37
Q

examples of findings on a diabetic retina

A

flame haemorrhages; hard exudate; blot haemorrhages

38
Q

side effects of prostoglandin analogues (3)

A
  1. red eye
  2. eyelash growth
  3. darkening of iris and skin
39
Q

side effects of carbonic anydrase inhibitors (3)

A
  1. blurred vision
  2. electrolyte disturbances
  3. tingling

3C week 1- intro to neuro and opthal (6 decks)

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