Orthoptists are awesome

Our clinic has a wide range of specialty practices including  two Orthoptists. 

An Orthoptist is an allied health care professional who specializes in the study of eye movements and binocular vision. They evaluate and diagnosis strabismus and amblyopia in all ages, under the supervision of an Ophthalmologist.  The Orthoptist  will bend images using a plastic Fresnel prism temporary adhered to the back surface of the patient's eyeglass lens. Prism amounts are measured in diopters and point in different directions. (Up, Down, In and Out). The prescription will indicate how much and which direction each person needs.  

Because they are a thin piece of plastic I use a scissors and a razor blade to shape them to the lens. 

It's very gratifying when the patient experiences immediate relief from double vision when they first try the prism on their lens. However it's not uncommon for the patient to have several follow up visits afterwards. 

These plastic press on prisms are an inexpensive temporary aid that help determine  what power works  best in the final prescription.