Binocular Vision

Question 1

What are the normal values for distance fusional reserves? (Blur/Break/Recover)

Answer 1

Convergence (BO) 4 / 20 / 12
Divergence (BI) - / 8 / 4
Vertical - / 4 / 2

Question 2

What are the normal values for near fusional reserves? (Blur/Break/Recover)

Answer 2

Convergence (BO) 8 / 30 / 20
Divergence (BI) - / 15 / 8
Vertical - / 4 / 2

Question 3

What are the reasons for an accommodative lag?

Answer 3

• Accommodative dysfunction
• Presbyopia or pre-presbyopia (if around 40)
• Uncorrected or under corrected hyperopia
• Over minused patient
• Esophoria with insufficient vergence (patient under-accommodates to keep fusion)
• Patient wasn’t paying attention during the test or the stimulus was too easy

Question 4

What are some of the reasons for accommodative lead?

Answer 4

• Spasm of accommodation –the system is locked up creating “pseudo-myopia”
• Exophoria with insufficient compensating vergence (patient over-accommodates to keep fusion)
• Uncorrected or under corrected myopia

Question 5

What VA distance test types can you use for younger children?

Answer 5

• Grating preferential viewing (babies)
• Cardiff cards (preferential looking - toddlers) (resolving the lines, otherwise appears grey)
• Kay pictures
• Cambridge cards
  (Crowded is always better)

Question 6

What near vision VA test charts can be used for children?

Answer 6

• Lea
• Kay near vision cards
• Child specific near vision text chart

Question 7

Explain how to do MEM retinoscopy…

Answer 7

Binocular at the WD that is suitable - their WD they use for reading.
Get them to look at the reading chart / pictures attached to the ret.
Use a MONOCULAR +1.00 and you should have against movement.