Visual Evoked Potentials VEPs will be recorded with Teca Synergy equipment (Viasys Healthcare). To ensures consistency in technique, the same technician will perform all three assessments (day 0, 30 and 180) on the same patient. The subject's skin will be cleaned for electrode placement. The scalp electrodes will be placed relative to bony landmarks, as per International Society for Clinical Electrophysiology of Vision (ISCEV) standards (40). The electrodes will be positioned 5 cm above the inion for Oz (active), mid-forehead for Fz (reference) and on the right arm for the ground, following ISCEV guidelines. The patient will be positioned comfortably in a chair with the eye at a distance of 1 meter from a 17-inch cathode ray tube (CRT) monitor, which has been found to be superior to an LCD monitor as the latter can cause a delay in the latency. The room will be darkened to minimize extraneous light that produce responses in the visual cortex and interfere with the VEP response. The same room will be used for every VEP in this study. The subject will be monitored for fixation as poor fixation can affect the P100 peak time and an eye patch used to isolate vision from one eye only. Monocular stimulation will occur at a frequency of 2 Hz, beginning with the unaffected eye, averaging 200 individual responses for each trial. A minimum of two trials per eye will be performed as per ISCEV guidelines. Further averaging of additional trials may be done if there are obvious technical problems (with visual fixation for instance). As the test is dependent on subject compliance, the following will take place to maximize compliance and technical aspects of the recording: talking and gum chewing will be prohibited; the subject will be instructed to relax all muscles of the head and neck specifically the jaw; feet will be resting flat on the floor with hands relaxed in the subject's lap; coaching will take place to help diminish any anxiety; the importance of fixation will be emphasized and the need to resist following the changes in colour of the checkerboard pattern and to continue fixating on the red fixation square in the centre of the monitor will be explained. The interpretation of the VEPs will be done by an assessor blinded to the treatment arm received.