Ophthalmology 2

Question 1

Visual acuity

Answer 1

the ability of the vision system to resolve (‘see’) a gap between two objects.

Question 2

spatial resolution

Answer 2

your visual system can no longer resolve the gap as you move your head away from fine lines

Question 3

how do you record visual acuity

Answer 3

You state however many meters you tested the eyes at e.g. 6 and then you state the line that the smallest text was seen on as a fraction e.g. 6/18

Question 4

LogMAR Visual Acuity

Answer 4

Logarithm of the Minimum Angle of Resolution

Question 5

Main difference in design of LogMAR visual acuity

Answer 5

• Same number of letters on each line with proportional spacing to the size of the letter
• Only uses ‘square’ shaped equally legible letters (Sloan)

Question 6

Advantages of LogMAR

Answer 6

• ‘Crowding’ phenomena is therefore equal for each line (unequal spacing between lines on Snellen)
• The letters change size by equal logarithmic steps (unequal changes in letter size in Snellen)
• You end up with a ‘number’ which is much easier to analyse statistically (rather than a x/y result in Snellen)

Question 7

‘Blind’ or Severe sight impairment (SSI) =

Answer 7

Worse than 3/60

Question 8

Partial Sight’ or Sight Impaired (SI) =

Answer 8

> 6/60 to 3/60

Question 9

Driving vision =

Answer 9

Better than or equal to 6/12

Question 10

Causes of an RAPD - relevant afferent pupil defect

Answer 10

• Asymmetrical disease of the retina or optic nerve
• Retinal detachment
• Optic neuritis
• Anterior ischaemic optic neuropathy(AION) • Tumour pressing on the optic nerve

Question 11

Fundal reflex test

Answer 11

• Quick
• Non-invasive
• Assess clarity of ‘media’ • Corneal scars
• Cataract
• Vitreous Bleeds
• Retinal tumours

Question 12

how do you perform a fundal reflex test

Answer 12

use ophthalmoscope to see “red eyes” in white children bu appears more white and bluish in black children

Question 13

What is the main abnormality seen here on fundal reflex test

Answer 13

loss of left retinal reflection

Question 14

Fundal Reflex Test can identify

Answer 14

• corneal scars
• cataract
• retinoblastoma

Question 15

What is the main abnormality seen here on fundal reflex test

Answer 15

central dark opacity in the left eye

Question 16

what is this

Answer 16

swollen disc

Question 17

• Pseudo swelling

Answer 17

– Small Discs

– Calcium deposits ‘Drusen’

Question 18

• Genuine swelling

Answer 18

• Optic Neuritis (VA reduced)
• Raised ICP (VA normal)
 – SOL
– IIH
– Hydrocephalus

Question 19

What are the three key elements that should be commented on when examining the optic nerve head?

Answer 19

Margin, colour and cup

Question 20

What systemic disease is associated with the clinical sign seen at this optic nerve head?

Answer 20

diabetes

Question 21

Eye Movements are controlled by what muscles

Answer 21

• 6 extra-ocular muscles
• 2 horizontal recti (medical and lateral)
• 2 vertical recti (superior and inferior)
• 2 oblique (superior and inferior)

Question 22

3rd CNP

Answer 22

• Vertical diplopia
• Eye is ‘down & out’
• Diplopia every where
• Pupil dilated and
ptosis
• Can be associated
with an aneurysm – needs urgent brain imaging and angiogram]
THINK ANEURYSM

Question 23

4th CNP

Answer 23

• Oblique diplopia •
• Head tilt away from side •
of the lesion
• Diplopia worse away from •
the side of the palsy if
unilateral (adduction)
• Common after head •
injury
• Bilateral - might be
congenital

THINK CONGENITAL OR TRAUMA

Question 24

6th CNP

Answer 24

• Horizontal diplopia
• Worse in far distance
• Worse towards the side of the palsy if unilateral
• Bilateral - concerned that raised intracranial pressure is present

THINK CRANIAL PRESSURE

Question 25

What is the main cause of blindness in low income countries

Answer 25

CATARACT

Question 26

What is the main cause of blindness in ‘wealthy’ countries

Answer 26

Age related macular degeneration