====== Optotype-Frame Test ======

  * Developed by Jonathan Holmes to detect central-peripheral rivalry-type diplopia
====Test sequence====
    * Patient fixates on a isolated optotype on an illuminated monitor at 3 meters
      * Use 20/40 sized optotype for those with VA 20/40 or better
      * If VA worse than 20/40 use the smallest recognizable optotype for the worse eye
    * The patient reports if the letter is single or double
    * Then while fixating on the central letter, they report whether the frame of the monitor is single or double 
===Results===
  * No diplopia = patient sees a single letter and single frame
  * Retinal misregistration = patient sees a double letter while seeing a single frame OR sees a single letter with a double frame
  * Strabismic diplopia = patient sees a double letter and double frame 

<WRAP simple round box 100%>
{{::optotype-frame_test.png|}}
Figure 1 from reference 1 below
</WRAP>


====References====
  - [[https://pmc.ncbi.nlm.nih.gov/articles/PMC5699521/pdf/nihms871601.pdf| Causes of Diplopia in Patients with Epiretinal Membranes. Veverka, K. et. al. Am J Ophthalmolol. 2017. 179:39-45]]