Training the Adult Amblyopic Eye with “Perceptual Learning” after Vision Loss in the Non-Amblyopic Eye

We recently reported (3 Fronius M, Cirina L, Cordey A, Ohrloff Ch. Visual improvement during psychophysical training in an adult amblyopic eye following visual loss in the contralateral eye. Graefe's Arch Clin Exp Ophthalmol 2005; 243: 278–280, [CROSSREF], [CSA][Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) acuity development in the amblyopic eye of a 60-year-old patient after loss of vision in her non-amblyopic eye. Here, we focus on the training that we implemented, based on new insights from psychophysical procedures aiming at functional visual improvement of adults (“perceptual learning” (6 Levi D M, Polat U. Neural plasticity in adults with amblyopia. Proc Natl Acad Sci USA 1996; 93: 6830–6834, [INFOTRIEVE], [CROSSREF], [CSA][Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; 7 Polat U, Ma-Naim T, Belkin M, Sagi D. Improving vision in adult amblyopia by perceptual learning. Proc Natl Acad Sci USA 2004; 101: 6692–6697, [INFOTRIEVE], [CROSSREF], [CSA][Crossref], [PubMed], [Web of Science ®] , [Google Scholar])). We alternately used the following procedures: grating acuity (Teller-Cards); contrast sensitivity (Vistech-Charts); two spatial localization tests (vertical alignment, pointing); and labyrinth patterns for a eye-hand coordination exercise. One month without intervention was followed by six months of training and two blocks of pleoptic treatment. Clinical parameters were assessed monthly.Besides acuity gain, we observed enhanced grating resolution and contrast sensitivity, decreased alignment distortions, pointing shifts, mainly after pleoptics, and more efficient labyrinth tracing. A questionnaire reflected the patient's perception of the changes.These data confirm the plasticity of the adult amblyopic system, be it spontaneous due to the loss of the non-amblyopic eye or caused by the intervention or both. Further experience is necessary to isolate the role of the intervention. Our results also underline the limitation of adult plasticity, emphasizing the importance of early diagnosis and treatment of amblyopia.