Visual Functional Connectivity and Visual Function in Amblyopia Before and After TMS and/or Binocular Treatment

Prior to the study, ocular misalignment and refraction abnormalities will be corrected This correction is part of standard patient care rather than a procedural component of the current study.

Procedure Participants will undergo one hour structural and functional MRI prior to their treatment. We will perform an interim analysis of the fMRI results once five amblyopic patients have completed the fMRI study. If the data shows significant differences in the resting state visual network in amblyopia patients compared to the existing normal visual resting state, we will pursue the fMRI study with the remaining 15 participants. Misalignment of the eyes will be corrected prior to a patients' participation by using prisms (if medically indicated). This correction is part of standard patient care rather than a procedural component of the current study. Participants will be randomly appointed to initially be in either the sham or the treatment group (10 patients in each group). All patients will receive five days of one hour visual binocular training by playing a specially designed falling blocks videogame on a computer screen that will be individually calibrated for each person. Group one will receive 18 minutes of rTMS at the beginning of their visual training every day for 5 days. Group two will receive 18 minutes of TMS followed by sham visual training every day for 5 days. At the end of five days, participants will switch groups. Participants will be blind as to whether they receive sham or real binocular treatment on each occasion.

A sensorimotor visual profile, including visual acuity, suppression, stereovision, binocularity, contrast sensitivity and eye alignment, will be completed for each patient at baseline, after five sessions, and at the end of the treatment. This profile will be completed using the PVVAT system, Worth-4-Dot test, Randot stereovision test, anaglyphic dichoptic coherence motion threshold with red-green glasses (using Psykinematix vision system), cross cover test with prism bars. fMRI will be repeated post-treatment only for individuals who showed abnormal fMRI at baseline. This second scan will investigate whether the treatment affected and normalized the resting state visual network.

Functional MRI:

All scanning will be performed on a 3.0 T Siemens Tim Trio scanner equipped with a 12-channel head coil. Scanning will take place on up to three visits: Pre-treatment (retinotopic mapping), and two post treatment scans.