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Year 4 - Neurology + Special Senses > Opthal - Preading > Flashcards

Opthal - Preading Flashcards

1
Q

What are the 3 C’s to remember when describing the optic disc on fundoscopy?

A
  • Cup
    • Cup-disc ratio - think of optic nerve as doughnut with blood vessels travelling through the middle
    • ↑ cup:disc ratio (e.g. 0.9) = nerve loss/degen making cup larger and disc smaller e.g. glaucoma
    • Normal cup:disc ratio = 0.3
  • Contour
    • ​Describe edge between optic nerve and retina
    • Blurred contour = swollen nerve
  • Colour
    • Normal = orange - pink
    • ​Pale - glaucoma, ON or optic neuropathy (NIGHT TIC)
      • Neuritis
      • Ischaemic
      • Granulomatous
      • Hereditory
      • Traumatic
      • Toxic
      • Irradiation
      • Compression
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2
Q

What technique can be used to visualise the blood vessels in the eye?

A

Fundus fluorescein angiography (FFA)

(image = normal)

  1. fluorescein injected into vein
  2. camera excites dye –> provides pictures
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3
Q

What type of imaging can be used to better view the retina?

A

optical coherence tomography (OCT)

(image = normal)

  • provides cross-sectional image of back of eye
  • shows layers of retina + pathologies
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4
Q

What additional questions / areas of history are needed in an opthalmic history?

A
  • HPC:
    • ​Any eye pain or redness?
    • One or both eyes?
    • Noticed any change in peripheral vision / central vision?
    • Up to date pair of glasses
  • Past opthalmic history:
    • previous surgery
    • short / longsighted
    • contact lenses or glasses worn or worn previously?
  • DH:
    • Anti-TB medication (e.g. ethambutol) SI include: ON
    • Amiodarone (antiarrhythmic) - SI include: ON, corneal deposits (causing corneal opacities)
    • Chloroquine / hydroxychloroquine (DMARDs) - SI include: retinopathy / bull’s eye retinopathy / maculopathy (see pic)
  • FHx:
    • Glaucoma
    • Dystrophy e.g. cone dystrophy
    • Blindness
  • SH:
    • Occupation
    • Driving (DVLA requies that you have at least 6/12 in one eye in order to drive)
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5
Q

What are the medical terms of short-sighted and long-sighted?

A
  • Short-sighted = myopia
    • ​Risk of retinal detatchment
  • Long-sighted = hypermetropia
    • ​Risk of acute glaucoma​
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6
Q

What signs on the retina can indicate hypertension?

A

Hypertensive retinopathy signs usually develop LATE in disease

  • Papilloedema (optic disc swelling)
    • Blurred contour of optic disc margin
    • Paton’s lines - concentric/radial lines cascading from optic disc
  • Retinal haemorrhages (flame haemorrhages)
  • Yellow hard exudates - lipid deposits with sharp margins
  • Cotton wool spots - white spots which represent swelling of retinal nerve fibres due to microinfarctions
    • Often near optic disc
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7
Q

Name some occular medical emergencies.

(5 listed)

A
  1. Central retinal artery occlusion (CRAO)
  2. Orbital cellulitis
  3. Retinal detachment
  4. Acute-angle closure glaucoma
  5. Giant cell arteritis
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8
Q

If the patients vision was 6/12 with corrected lenses what should be your next course of action?

  • Refer to opthalmologist
  • Send to opticians for new lenses
  • Re-test with pin-holes
A

Re-test with pin holes

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9
Q

What is the purpose of pin-hole testing?

A

Pin holes allow only central rays of light in to they eye which means that it will correct for a certain amount of refractive error allowing you to differentiate between:

  • Refractive errors (in which case sent to the opticians)
  • Eye pathology (in which case refer to the ophthalmologist)

Note: record visual acuity with glasses/lenses and record if PH was done e.g. left eye (with glasses) PH 6/12

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10
Q

Which of the following are correct.

The retina consists of:

  • The retinal pigment epithelium, a multi-layer group of cells
  • Photoreceptors called rods and cones
  • An inner and outer plexiform layer
  • 9 layers
A

Photoreceptors called rods and cones

&

An inner and outer plexiform layer

  • The retinal pigment epithelium (farthest from vitrious body) is a MONO-layer of cells
  • The retina has 10 layers total
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11
Q

Which of the following are correct.

The cornea:

  • Consists of 5 layers
  • Is avascular
  • Is the only structure in the eye responsible for focusing light (refraction of light)
  • Is composed of regular arranged collagen fibres
A
  • Consists of 5 layers
  • Is avascular
  • Is composed of regular arranged collagen fibres
    • Sclera = irregular alignment of collage fibres
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12
Q

Patients describe eye pain as the following - what do they indicate?

  • Grittiness, dryness eyes feel tired / want to close
  • Sharp / stabbing pain “like needles”
  • Dull ache
A
  • Grittiness, dryness eyes feel tired / want to close
    • Dry eye
  • Sharp / stabbing pain “like needles”
    • Ocular surface problem
  • Dull ache - like toothache
    • Uveitis /↑ IOP / scleritis
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13
Q

For each lesion location describe the visual field loss.

A
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14
Q

Briefly describe the procedure for fundoscopy.

A

For each eye:

  1. Check equipment
    • Check opthalmoscope is charged
  2. Dilate eyes as per hospital guidelines
  3. Dim lights where possible
  4. Set ophthalmoscope lens dial to 0
  5. Check for red reflex – no red reflex, no fundoscopy!
  6. Move in closer and look for retinal vessel
  7. Follow retinal vessel to optic disc
  8. Cup – colour – contour
  9. Follow 4 vascular arcades
  10. Ask patient to look up, down, left and right to check for peripheral changes
  11. Ask the patient to look directly in to the light to check the macular
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15
Q

What are the normal visual field ranges in each direction?

A
  • Superior - 50 degrees
  • Nasally - 60 degrees
  • Inferior - 70 degrees
  • Temporally - 90 degrees
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16
Q

Name some causes of ‘central’ visual field loss.

A
  • Age-related macular degeneration
  • Optic neuropathy
  • Retinal artery occlusion
  • Macular holes - small break in macula
  • Cone dystrophies - inherited loss of cone cells
  • Leber’s hereditary optic neuropathy - mitchondrially inherited degen of retinal ganglion cells
17
Q

Name some causes of peripheral visual loss.

A
  • Glaucoma (angle-closure glaucoma and open-angle glaucoma)
  • Retinal detatchment
  • Retinitis pigmentosa - genetic, progressive loss of rod cells (often followed by loss of cone cells)
  • Chorioretinitis - inflammation of the choroid (pigmented vascular coat of the eye) + retina
    • Type of posterior uveitis
    • Cause = often toxoplasma gondii or cytomegalovirus infections (seen in immunodeficient), but also; syphilis, sarcoidosis, TB
  • Branch retinal artery occlusion
18
Q

What is a scotoma?

A

Scotoma = visual field defect surrounded by normal visual field

  • Can begin as gradual enlargement of blind spot
  • Relative scotoma = area where objects of low luminance can’t be seen but large / bright objects can
  • Absolute scotoma = nothing seen in affected area of visual field
19
Q

What pathologies could cause the following visual field defects?

(see image)

A
20
Q

How many vascular arcades supplying the retina are there?

A

4

  1. Superior temporal
  2. Superior nasal
  3. Inferior temporal
  4. Inferior nasal
21
Q

Dilating medication is often used prior to examination with opthalmoscope.

Name 3 pupil dilating agents.

A
  1. Tropicamide 1% - anti-muscarinic
  2. Cyclopentolate 1% - muscarinic ACh-R antagonist
    • These dilating drops can be used in children
  3. Phenylephrine 2.5% - sympathomimetic

Note: caution not to use this in patients at risk of or Hx of glaucoma

Year 4 - Neurology + Special Senses (12 decks)

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