Visual Loss

Question 1

What does myopia mean?

Answer 1

Near sightedness

Question 2

What does hypermetropia mean?

Answer 2

Long sightedness

Question 3

What does presbyopia mean?

Answer 3

Long sightedness due to loss of elasticity in eyes

Question 4

What is the presentation of macular degeneration?

Answer 4

Gradual worsening central visual field loss
Reduced visual acuity
Crooked or wavy appearance to straight lines

Onset is more acute in wet macular degeneration

Question 5

What is the pathophysiology of wet and dry macular degeneration?

Answer 5

Wet: neovascularisation growing from the choroid layer into the retina. these vessels can cause oedema and quicker vision loss. VEGF stimulates this.

Dry: atrophy of the neuro-retina, gradual loss of vision, drusen are present, changes in pigmentation of retinal epithelium

Question 6

What are the features that are the same in wet and dry AMD?

Answer 6

Atrophy of retinal pigment epithelium
Degeneration of photoreceptors
Drusen present

Question 7

What are the investigations of macular degeneration?

Answer 7

Examination: scotoma (patch of visual loss), Amsler grid test (shows distortion of straight lines), fundoscopy

Slit lamp fundus examination
Optical coherence tomography

Question 8

What is the management of dry and wet macular degeneration?

Answer 8

Dry: stop smoking, control BP
Wet: anti-VEGF (-mab). Injected directly into vitreous chamber once a month.

Question 9

What is diplopia? What are the causes of diplopia?

Answer 9

Double vision
Usually due to impaired extra ocular muscles

Binocular: squint (‘strabismus’ eyes pointing in different directions)
Monocular: astigmatism, dry eyes, cataracts

Question 10

What causes pupil constriction?

Answer 10

Parasympathetic nervous system using ACh

Oculomotor nerve

Question 11

What causes pupil dilation?

Answer 11

Sympathetic nervous system using adrenaline

Dilator muscles

Question 12

What type of pupil is seen in migraines?

Answer 12

Tadpole pupil can be seen

Question 13

How does a third nerve palsy present?

Answer 13

Ptosis
Dilated non reactive pupil
Down and out position of eye

Question 14

What are the causes of a third nerve palsy?

Answer 14

With sparing of the pupil: diabetes, HTN, ischaemia

Without sparing of pupil: tumour, trauma, cavernous sinus thrombosis, raised ICP

Question 15

What is Horner syndrome?

Answer 15

Ptosis
Miosis
Anhidrosis (loss of sweating)

Caused by damage of the sympathetic nervous system supplying the face

Question 16

What are the causes of Horner Syndrome?

Answer 16

Central lesions: anhidrosis of arm, trunk and face (4S's)
Stroke
Multiple sclerosis
Swelling (tumours)
Syringomelia 

Pre-ganglionic lesions: anhidrosis of the face (4T's)
Tumour
Trauma
Thyroidectomy
Top rib 

Post-ganglionic lesions: no anhidrosis (4 C's)
Carotid aneurysm
Carotid artery dissection
Cavernous sinus thrombosis
Cluster headache

Question 17

What is the management of Horner Syndrome?

Answer 17

Cocaine eye drops (stop noradrenalin uptake at NMJ)

Adrenaline eye drop

Question 18

What is a Holmes-Adie pupil?

Answer 18

Unilateral dilated pupil
Sluggish to react to light
Slow dilatation following constriction

Damage to post ganglionic parasympathetic fibres

Question 19

What is a Argyll-Roberston pupil?

Answer 19

Found in neurosyphilis
‘Accommodates but does not react’
Constricted pupil that focuses on a near object but does not react to light

Question 20

What are the DVLA requirements for vision loss?

Answer 20

Bilateral glaucoma, retinitis pigmentosa, bilateral retinopathy = must inform the DVLA, can drive

Diplopia = must inform the DVLA, cannot drive

Colour blindness = do not have to inform the DVLA, can drive

Question 21

What are the minimum requirements for driving under the DVLA?

Answer 21

Snellen chart: must at least be 6/12 in each eye

Higher standards for bus and lorry drivers.

Question 22

What are the signs of papilloedema?

Answer 22

Loss of optic cup
Loss of venous pulsation
Blurring of optic disc margin