====== Prism Adaptation for Esotropia ======
  * Prism Adaptation Study
    * Randomized controlled trial
    * Provides an evidence based paradigm for treatment
===== Candidates =====
  * Acquired Esotropia
  * Partially Accommodative Esotropia
  * Esotropia with Near > Distance 
  * Exotropia has not been investigated thoroughly with this procedure 

===== Procedure =====
  * Add Fresnel prism to glasses
  * Try to split prism equally with larger prism over eye with worse acuity if needed

===== Possible Outcomes =====
  * **Non-Responder**
    * Orthotropic but no sensory response
      * Keep prisms on and check immediately before surgery 
    * Exotropia of any size
    * Stop and do surgery for entry angle
  * **Responder**
    * ≤ 8 Prism Diopers on Simultaneous prism cover test at distance and near and
    * Peripheral fusion on Worth 4 Dot test or
    * Stereo response on Titmus Stereo test
    * Surgery for angle at response
  * **Builder**
    * > 8 Prism Diopters on Simultaneous prism cover test
    * Add more prism and recheck in a week
===== Surgical Dose Table =====
^  Target Angle (PD)   ^  BMRc   ^  LRs (one eye)   ^
| 12 - 15            | 3.0   | -              |
| 16 - 20            | 3.5   | -              |
| 21 - 25            | 4.0   | -              |
| 26 - 30            | 4.5   | -              |
| 31 - 35            | 5.0   | -              |
| 36 - 40            | 5.5   | -              |
| 41 - 45            | 6.0   | -              |
| 46 - 50            | 5.0   | 5.0            |
| 51 - 55            | 5.0   | 6.0            |
| 56 - 60            | 5.0   | 7.0            |

===== References =====
  * [[http://archopht.jamanetwork.com/article.aspx?articleid=638654 | Prism adaption for Acquired Esotropia (6 months outcome data)]]
  * [[http://www.aaojournal.org/article/S0161-6420(96)30586-1/abstract|One-Year Surgical Outcome after Prism Adaptation for Acquired Esotropia]]