Bioengineering Basis for VT

Question 1

In terms of training phasic controllers with lenses, rank the following from easiest to hardest:

BIM/BOP
BOM/BIP
BI/BO or +/- only

Answer 1

BOM/BIP (easiest)
BI/BO or +/- only
BIM/BOP (hardest)

Question 2

True or false: in the bioengineering model of accommodation and vergence, adaptive controllers play into the AC/A and CA/C ratios.

Answer 2

False; they do not. This is why adaptive training can help to reduce accommodative and vergence symptoms. If the adaptive controller works better, there is less accommodation/vergence cross-talk. (Note that the original model does show adaptive controllers playing into the ratio, Cooper’s modified model shows that they do not.)

Question 3

How can you maximally stimulate the adaptive controller during adaptive training?

Answer 3

Make large changes, all at once (without ramping). Hold the activity for up to two minutes.

Question 4

What is the difference between passive error and active error, when referring to either accommodation or vergence?

Answer 4

Passive error is where the vergence or accommodative system ends up after making its first big movement toward the target of regard. Active error is where the system ends up after getting the target close enough to land in either Panum’s area or within the DOF. (Active error yields accommodative and vergence postures.)

Question 5

Before starting any VT, what should you do for the patient’s vision?

Answer 5

Get them the best prescription. Since this is what they’ll be looking through, you need to establish this as the baseline. Then you can plan where you want the therapy to go.

Question 6

A plus add will limit the phasic response. This, in turn, limits the adaptation requirements for accommodation and eventually the AC/A influence. Because of this, you may need _____ (more/less) plus to achieve the desired results.

Answer 6

Less

Question 7

True or false: VT devices are magic.

Answer 7

False. Though if you could incorporate Bop-It into a VT session, that would be cool.

Question 8

The whole scheme of planning VT involves the following phases:

Stimulus sensitivity
Phasic training
Specific skill training
Adaptive training

What training exercises can help to bring awareness of accommodation and voluntary control of accommodation?

Answer 8

Plus blur/lens sorting (for blur sensitivity), plus and/or BO walk away and split pupil rock (for awareness of accommodation and voluntary control of accommodation)

Question 9

The whole scheme of planning VT involves the following phases:

Stimulus sensitivity
Phasic training
Specific skill training
Adaptive training

What training exercises can help to bring awareness of vergence?

Answer 9

Prism sensitivity/sorting, disparity/position sensitivity, Brock string, etc.

Question 10

The phasic controllers of accommodation and vergence are important to daily visual tasks, and their dysfunction is correlated with asthenopia. What visual exercise is commonly used to help train the phasic controller?

Answer 10

Facilities–plus/minus or prism flippers, or a combination (BIM/BOP or BIP/BOM)
Near-Far rock