When you are performing BO & BI ranges, remember what you are actually testing for:
Blur: Occurs from the loss of accommodation away from the object plane (our system will sacrifice clarity before singleness)
Break: Represents the loss of fusion when the limit of fusional vergence is reached
Recovery: Consists of the person’s ability to voluntarily converge/diverge in response to spatial disparity (sensory information!)
* Bonus Pearl: The recovery is probably the most important factor- it represents the patients ability to voluntarily regain fusion. This is the key to understanding your patients functioning!