Retinal Disorders Flashcards Preview

S2.3 Neurology > Retinal Disorders > Flashcards

Flashcards in Retinal Disorders Deck (13)
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1
Q

What retinal diseases can lead to sudden painless loss of vision?

A
Central retinal vein occlusion
Central retinal artery occlusion
Ischaemic optic neuropathy
Stroke
Vitreous haemorrhage
Retinal detachment
Sudden discovery of pre-existing unilateral LoV
2
Q

What retinal conditions cause gradual painless loss of vision?

A
Cataracts
Refractive error
Age-related macular degeneration
Open angle glaucoma
Diabetic retinopathy
Hypertensive retinopathy
Inherited retinal dystrophies
Drug-induced retinopathy
3
Q

How does the retina appear in central artery/vein occlusion?

A

Artery occlusion

  • Pale retina
  • Cherry red macula
  • Vessel attenuation
  • Cattle-tracking

Vein occlusion

  • Tortuous dilated veins
  • Optic disc swelling
  • Might have cotton wool spots
  • Widespread haemorrhage
4
Q

How do optic neuritis and ischaemic optic neuropathies develop?

A

Ischaemic Optic neuropathies

  • Arteritic (AION) - Giant-cell arteritis
  • Non-arteritic (NAION) - optic disc shape and CV risk factors

Optic neuritis

  • infections
  • toxins
  • neurological disorders
5
Q

Signs/symptoms of optic neuritis?

A
Pain on eye movements
Reduced vision
Red desaturation
Central scotoma
Relative afferent pupil defect
Swollen optic disc
6
Q

Signs/symptoms of ischaemic optic neuropathies

A
Sudden, painless loss of vision
Giant cell arteritis symptoms
- headache
- scalp tenderness
- jaw claudication
- neck pain
- nausea/anorexia
- raised inflammatory markers
- temporal artery biopsy
7
Q

What is age-related macular degeneration and what are the risk factors?

A
Progressive loss of central vision
Dry type (80-90%) and wet type (blood, fluid)

Age
Smoking
Poor Diet

8
Q

What is a retinal dystrophy?

A

Series of inherited conditions affecting photoreceptor function leading to progressive loss of vision
E.g. retinitis pigmentosa
Can be photoreceptor or retinal pigment epithelium (RPE)

9
Q

What is retinitis pigmentosa?

A
Photoreceptor dystrophy
1:4000 inheritance
Predominantly rod-related
20% Sporadic
40% Dominant
20% Recessive
10
Q

How would photoreceptor dystrophies compare to retinal pigment epithelium (RPE)-dystrophies in terms of investigation results?

A

Photoreceptor dystrophies have reduced Electroretinogram

RPE dystrophies have reduced Electrooculogram

11
Q

What investigations are used in retinal disorders?

A
Acuity, fields, colour vision, relative afference pupillary defect
Fundoscopy
Fluorescein angiography
Optical coherence tomography
Electroretinogram (ERG)
Electrooculogram (EOG)
Visually-evoked potentials (VEP)
12
Q

How does each electrophysiology retinal test work?

A

Electroretinogram

  • measures retinal function via action potentials
  • a-waves from photoreceptors, b-waves from Muller’s cells

Electrooculogam

  • measures function of retinal pigment epithelium and photoreceptors via resting potential difference between the RPE and photoreceptors
  • max potential difference in light adapted eye
  • minimum potential difference in dark adapted eye
  • Arden ratio 1.85

VEP

  • records optic nerve function
  • measures electrical activity in the visual cortex in response to either a flashing light or a checker board pattern
  • reduced amplitude = reduced cell number > ischaemic/traumatic optic neuropathy
  • latency = reduced cell function > optic neuritis (demyelination)
13
Q

How can newer therapies be used to treat retinal pathology?

A

Choroideraemia - (choroidal dystrophy) - x-linked recessive

  • gene therapy
  • viral vector to insert replacement gene

Bionic eye
- Retinal implant of 60 electrodes connected to camera