Tuesday, October 16, 2012
Neuroscientists interested ini treating adults with amblyoia
Authors: *B. MANSOURI1, B. SCHMIDT1, P. SING1, P. PEARSON2, A. GLOBA2;
1Univ. Manitoba, Winnipeg, MB, Canada; 2Psychology, Univ. of Winnipeg, Winnipeg, MB, Canada
Objectives: Amblyopia is the most common cause of impaired vision in one eye. Although patching the fellow eye has been shown to be effective in treating children, there has been no clinically approved treatment available for amblyopic adults. The current study reports the result of a clinical trial of a new treatment that is based upon recent demonstrations of neuroplasticity in adults with amblyopia.
Methods: Sixteen adults (mean 37±18 years) with mild, moderate and severe amblyopia (visual acuity (VA) of 20/40-50, 20/63-100 and 20/120 or less, respectively) and two control participants (VA 20/20) completed 18 sessions of visual binocular training. Training involved random dot kinematograms presented dichoptically for 500ms using stereo-goggles, where target dots moved to the left and right of the screen and noise dots moved in random direction. The participants’ task was to identify the direction of motion of the targets. First, binocular motion discrimination threshold was measured as signal to noise ratio for each patient (i.e. binocular threshold). Then, using the previously obtained signal/noise ratio, targets were presented to the amblyopic eye with high contrast whereas noise was presented to the fellow eye with relatively lower contrast. The difference in contrast of the stimuli presented to the two eyes was uniquely determined for each patient based upon the contrast of noise dots that permitted binocular combination of the information from the two eyes (balance-point). We frequently measured the binocular threshold and VA for each patient across the training sessions and adjusted the signal/noise ratio according to patients’ improvement in binocular motion discrimination. We used student one-sample T-Test and correlation coefficient to analyze the data.
Conclusion: Our results demonstrated that binocular treatment of amblyopia improved VA on average by 4 lines
Comments: I'm thrilled that neuroscientists can now feel confident that amblyopia can be treated in adults....especially since for decades they said if you were older than 6 it was impossible! I'm not quite sure what they mean by " no clinically approved treatment available for amblyopic adults"...adults have been treated for amblyopia by functional optometrists for many years....using clinically approved techniques....meaning that they worked! I would strongly suggest that our neuro-scientist colleagues check out the optometric literature on this topic. Look for articles by Nate Flax, Bill Ludlam, and many others. (Go beyond PubMed) DM