A functional visual field (or peripheral vision test) with a syntonic certified assistant takes place, then is interpreted by a doctor of optometry who is certified in syntonics. The results of the testing help determine the light filters and sequences to be used. Treatments are typically 3 times per week at the same time each day. However, 2 treatments can take place in the same day as long as there is at least 4 hours between the sessions. The number of treatments vary from patient to patient but usually after 6 sessions, a repeat of the visual field is performed to assess progress.