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Neurology and Special Senses > Practical Opthalmology > Flashcards

Practical Opthalmology Flashcards

1
Q

How is distance vision tested?

A

Snellen chart

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2
Q

How is a snellen chart used?

A

Pt stand 6m away from chart and read smallest line they can

Vision less than 6/6 - repeat with pinhole to eliminate refractive errors

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3
Q

How does the scoring of a snellen chart work?

A 
Numerator = 6 - 6m away (or 20 for 20ft)
Denominator = smallest line they can read (60, 36, 24, 18, 12, 9, 6 as go down chart)
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4
Q

What do you do if a patient can’t read the largest letter?

A

Count how many fingers
See if they can see a hand moving
Check for perception of light

If none - classified as no perception of light

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5
Q

How is near vision tested?

A

Near reading chart

Smallest = N5
Largest = N48
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6
Q

How is colour vision tested? How is it scored?

A

Ishihara plates

Numerical score based on no. of correct responses

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7
Q

What is the first thing you check when testing a patients eyes using an ophthalmoscope?

A

Red reflex

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8
Q

When is a red reflex abnormal?

A

Asymmetry
Dark spots
Absent reflex

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9
Q

How do you test for gross visual defects?

A

Confrontation testing

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10
Q

What is the perimeter testing of visual fields?

A

It is the machine testing that gives in-depth details of visual fields

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11
Q

What are the parts to the perimeter test of visual fields?

A

Grey scale
Total deviation
Pattern deviation

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12
Q

What does grey scale perimeter show you?

A

Generalised picture

Done with other plots and not alone for diagnosis!

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13
Q

What does total deviation perimeter show you?

A

Which parts of patients visual field that are different to age matched norm

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14
Q

What does pattern deviation perimeter show you?

A

Localised visual field defects by removing generalised defects such as those caused by cataract

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15
Q

What happens in the cover test?

A

Focus on object in front and one eye occluded for several seconds

Observe for movement of uncovered eye

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16
Q

What does a cover test show?

A

If eye move out - esotropia
If eye move in - exotropia

(shows misalignment of eyes)

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17
Q

What happens in the alternate cover test?

A

Focus on object in front

Occluder rapidly switched from one eye to other

18
Q

What does an alternate cover test show?

A

Eye move out - latent esophoria

Eye move in - latent exophoria

19
Q

What is the difference between esophoria and esotropia?

A

Esophoria - small turning-in of eye

Esotropia - large turning-in of eye

20
Q

What nerves are involved in the corneal reflex?

A

Afferent - ophthalmic branch of trigeminal

Efferent - facial nerve

21
Q

How do you test the corneal reflex?

A

Approach eye from side (out of line of vision)
Lightly touch thing strand of cotton on cornea

Watch for direct and consensual reflex of blinking and watering

22
Q

What does the swinging flash light test look for?

A

Relative afferent pupillary defect

23
Q

How is the swinging light test conducted?

A

Patient look at distant target in dimly lit room

Light moved as fast as possible between 2 eyes (2s per eye)

24
Q

What is a normal swinging light reflex?

A

When beam swung from eye to eye, bilateral pupil constriction shouldn’t change

Pupils hold constriction

25
Q

What swinging light reflex is seen in patients with a relative afferent pupillary defect?

A

When light shone on abnormal pupil, both pupils appear to dilate as their degree of constriction reduces

Known as a Marcus Gunn pupil

26
Q

If a patient has an efferent pupillary defect, what is seen on a swinging light test?

A

Affected eye constriction poor

Consensual pupillary reflex unaffected

27
Q

What do you look for on fundoscopy?

A 
Optic disk
Optic cup
Fovea
Macula
Retinal arteries and veins
28
Q

What are the uses of mydriatic drops?

A

Dilate pupil for visualisation of the retina
Paralyse accommodation in management of children with amblyopia
Refraction of children for prescription of glasses

29
Q

What side effects are associated with mydriatic drops?

A

Whitening of the eyelids - vasoconstriction (resolve as drops wear off)
Atropine cause redness of face and warm sensation
Sting eyes for few seconds after instillation
Can’t drive - blurring until wear off

30
Q

What must you inform patients of in consenting for mydriatic drops?

A

What procedure involve
Can’t drive
Effects - dilation and stinging
Check allergies and CI

31
Q

How are mydriatic drops applied?

A

Pt look up and pull inferior eyelid down
Apply one drop from vertical position
Allow pt to blink
Wipe away excess

32
Q

What must you document following the use of mydriatic drops?

A

Type of drop
Which eye
How many drops
Time of instillation

33
Q

What are the types of mydriatic drops?

A

Atropine
Cyclopentolate
Tropicamide
Phenylephirine

34
Q

What are the mechanisms by which mydriatic drops work?

A

Parasympatholytics - atropine, cyclopentolate, tropicamide

Sympathetic agonist - phenyephirine

35
Q

What are the contraindications for atropine? How long does the effect last?

A

Hypertension
Untreated narrow angle glaucoma

1-2 weeks effect

36
Q

What are the contraindications for cyclopentolate or tropicamide? How long does their effect last?

A

Untreated narrow angle glaucoma
Allergy

Cyclopentolate 25-75 min effect, recovery over 6-24hrs
Tropicamide 15-20 min effect, recovery 4-8hrs

37
Q

What are the contraindications of phenylephrine? How long does its effect last?

A

Untreated narrow angle glaucoma
Avoid in children

3-6 hours effect

38
Q

What are fluorescein drops used for?

A

Highlight defects in the cornea

Measuring intraocular pressure with tonometry

39
Q

What adverse drug reactions are associated with fluoroscein drops?

A

Skin discolouration - 6-12 hrs

40
Q

What should you warn patients of when giving fluoroscein drops?

A

Don’t put contacts in for an hour as they could be stained permanently

41
Q

What is fluorescein angiography used for?

A

Look at vascular supply of retina and choroid

42
Q

How is fluoroscein angiography carried out?

A

IV injection of fluoroscein which delineate retinal vessels

Photographic record made including leakage from retinal vessels over 15 mins

Neurology and Special Senses (28 decks)

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