Opthalmology

Question 1

Draw out the following visual field defects.

1. RIght anopsia
2. Bitemporal hemianopsia
3. Left homonymour hemianopsia
4. Left upper quadrantic anopsia
5. Left lower quandrantic anopsia
6. Left hemianopsia with macular sparing

Answer 1

Question 2

Name the anatomy

Answer 2

Question 3

Name the anatomy

Answer 3

Question 4

What are the leading causes of avoidable blindness?

Answer 4

• glaucoma (12.3%)
• corneal opacities (5.1%)
• diabetic retinopathy (4.8%)
• childhood blindness (3.9%)
• trachoma (3.6%)
• onchocerciasis (0.8%)

Question 5

What does this image show and what are the causes of this?

Answer 5

Optic atrophy

• Causes include:
  
  • Glaucoma
  • Optic neuritis (demyelination/MS)
  • Ophthalmic artery occlusion (giant cell arteritis/stroke)
  • Compression (pituitary tumour)
  • Hereditary causes:
    
    • Friedreich’s atxia
    • Dystrophia myotonia
    • Leber’s optic atrophy

Question 6

What does a third nerve palsy cause?

Answer 6

• Upper lid ptosis - The levator palpebrae superioris muscle is jointly responsible for elevating the upper lid. It is supplied by the superior division of the oculomotor nerve and will therefore have impaired function in a third nerve palsy.
• Abduction and infraduction of the globe - typically referred to as a “down and out” eye position. As the oculomotor nerve supplies the medial, superior and inferior recti as well as the inferior oblique muscle, in a third nerve palsy the only muscles which exert a force on the globe are the superior oblique (causes downwards rotation) and the lateral rectus (causes outwards rotation or a divergent squint).
• A dilated pupil - Pupil constriction is mediated by the sphincter pupillae muscles innervated by parasympathetic fibres third nerve (inferior division). When parasympathetic supply is disrupted in a third nerve palsy sympathetic tone is unopposed and will therefore cause pupil dilatation.