Eyes

Question 1

What is the DVLA requirements for minimal eyesight?

Answer 1

Acuity - 6//10

Visual field - <20 degrees

Question 2

What is inflammation of the cornea called?

Answer 2

Keratis

Question 3

What three substances form tears and what secretes them?

Answer 3

Mucus - conjunctival goblet cells
Water - Lacrimal gland
Lipids - Meibomian gland

Question 4

Describe how aqueous humour drains from the eyes?

Answer 4

Leaves the anterior chamber and travels through the trabecular mesh-work and leaves via the canals of schlem

Question 5

What is normal intra-ocular eye pressure?

Answer 5

15.5 mmHg

Question 6

What do rod and cone cells synapse onto?

Answer 6

Rod - On bi-polar cell

Cone - On and Off bi-polar cell

Question 7

Describe phototransduction?

Answer 7

Photons hit the photoreceptor cells and hyper-polarise them. G-protein rector activation (Opsin which is Vit A bound) isomerises leading to Transducin enzyme activating the enzyme phospodiesterase, this hydrolyses cGMP and lowers its level which in turn blocks sodium channels

Question 8

On the lateral geniculate nucleus describe how macula and peripheral fibres synapse?

Answer 8

Macula fibres - Medial

Peripheral fibres - Lateral

Question 9

Describe the optic radiations?

Answer 9

Upper retinal fibres travel directly posterior

Lower retinal fibres travel temporally (Meyer’s loop)

Question 10

Define low vision?

Answer 10

3//60

Visual field loss of <20 degrees

Question 11

Define blindness?

Answer 11

<10 degrees

Question 12

A lesion of the macula will cause what field defect?

Answer 12

Unilateral central scatoma with distortion

Question 13

Acute optic nerve lesion will cause what field defect?

Answer 13

Unilateral central scatoma

Question 14

In the pupillary light reflex, where does the optic tract synapse?

Answer 14

Pre-tectal nucleus (bypassing the lateral geniculate)

Fibres are then sent to the Edinger/Westphall

Question 15

Describe the relative afferent pupillary defect?

Answer 15

Shine a light in affected eye = No constriction in either pupil, shine light in normal eye and both pupils will constrict (consensual and direct response), shine light in affected eye again and both eyes dilate

Question 16

What is RAPD indicative of?

Answer 16

Optic nerve (CN II damage)
Retinal detachment

Question 17

Describe the pupils of patients with afferent defects against those with efferent defects at rest?

Answer 17

Afferent problems - both pupils same size at rest

Efferent problems - both pupils different size at rest

Question 18

Describe what can efferent defects?

Answer 18

Failure to constrict - CN (III) palsy/acute glaucoma

Failure to dilate - Horner’s syndrome/ Uvitis

Question 19

Describe medical conditions that may bring about painful sudden loss of vision?

Answer 19

Acute (open-angled) glaucoma

Optic nerve neuritis

Question 20

Describe medical conditions that may bring about painless sudden loss of vision?

Answer 20

Retinal detachment
Macular degeneration WET
Vitreous haemorrhage

Question 21

Describe medical conditions that may bring about a gradual loss of vision?

Answer 21

Cataracts
Chronic glaucoma
Optic nerve and pathway tumours
Macular degeneration DRY