This is a relatively brief post to bring to your attention a continuing education article now available online through Clinical & Refractive Optometry titled Dichoptic Treatment of Amblyopia in a Clinical Setting – a Retrospective Study, authored by Giovanni M. Travi, MD, Seyedbehrad Dehnad, and Behzad Mansouri, MD, PhD, FRCSC. Dr. Travi is an ophthalmologist and biomedical engineer; Dr. Mansouri is a neuro-ophthalmologist; and Seyedbehrad Dehnad is their research assistant at the University of Manitoba in Winnipeg, Canada. If Dr. Mansouri’s name seems familiar, it is likely because he is a co-author of the paper in Restorative Neurology and Neuroscience, along with Hess and Thompson at McGill University in Canada in 2010, that introduced dichoptic training of amblyopia into the literature.
I like the authors’ description of amblyopia, contained in the introduction to this paper:
Amblyopia is an abnormal development of the visual system secondary to its inadequate (i.e. anisometropia and deprivation amblyopia) or erroneous (i.e. strabismic amblyopia) binocular stimulation during early visual development. It is usually unilateral, and it occurs due to a mismatch of information between the two eyes. Beyond affecting the visual acuity, amblyopia affects contrast sensitivity, spatial integration, global motion perception, and depth perception. Moreover, it may impact negatively the quality of life, either due to the low vision in the amblyopic eye, weak depth perception or because of the social burden of the most widely used treatment, i.e. occlusion therapy. Recently, the understanding of unilateral amblyopia physiopathology has evolved and the concept that the visual loss is related uniquely to an abnormally developed visual system has given place to the one based on an anomalous binocular interaction.
Here is the authors’ abstract:
Purpose: Dichoptic visual stimulation has been evolving as a promising treatment for amblyopia. We aimed to assess the visual outcomes of Dichoptic Amblyopia Treatment (DAT) in a clinical setting for patients who had completed all conventional amblyopia treatments and did not have any other clinical treatment options. The primary outcome was the improvement of visual acuity (VA) in children and adults. The secondary outcomes were improvement in stereo acuity (SA) and reduction of suppression.
Methods: We performed a retrospective chart review of amblyopic patients who received DAT from 2014 to 2016 in an eye care practice. DAT consisted of playing “Falling Cubes” game on an iPod, using dichoptic presentation.
Results: 23 patients with a median age of 12 years-old (Interquartile range (IQR) = 9-30) met the inclusion criteria. 3 patients were excluded on the final VA analysis due to non-completion of treatment. The median for pre- and post- treatment VA was 0.54 (IQR=0.41-0.84) and 0.19 (IQR=0.09- 0.28) logMAR, respectively. Mean improvement in VA was 0.33 ± 0.18 logMAR (IQR=0.25-0.41) (p<0.001). Patients showed an improvement in SA (p=0.002) and a decrease in suppression (p=0.003). Age group, presence of SA at baseline, previous treatment, amblyopia type and severity did not correlate with VA improvement. There was no adverse effect such as double vision or VA reduction in the sound eye.
Conclusion: To the best of our knowledge we showed for the first time that DAT is a plausible amblyopia treatment at a clinical environment. The results demonstrate that DAT is effective in improving VA and SA, and reducing suppression in amblyopia. We emphasize the importance of an active follow-up regarding game monitoring and frequent patient’s reassessments.