[Clinical study of visual plasticity in teenage and adults with amblyopia]

Human visual plasticity was studied by the observation of the effects of treatment in teenage and adult amblyopia.

One hundred and two cases (125 eyes) were diagnosed as amblyopia according to the national criteria of amblyopia. These patients were divided into teenage group (15 - 17 years old, 47 cases and 57 eyes) and adult group (18 - 45 years old, 55 cases and 68 eyes). Eye examination, including best correct visual acuity, laser interference fringes visual acuity (IVA), degree and patterns of amblyopia, and nature of fixation were performed in these two groups before amblyopic treatment. Patients were treated with correct spectacle, optical and drug penalization (including far and near penalization, as well as light penalization), combined with occlusion and assisted with red light pleoption. All patients were followed up for 1 - 5 years, with an average of 2.9 years.

Fifty five eyes (44%) were cured (23 eyes recovered, 32 eyes basically cured), 37 eyes (29.6%) were improved, 33 eyes (26.4%) were nullified and the total improvement rate was 73.6%. Different ages did not influence the results of treatment significantly (P > 0.05). Outcome of foveal fixation and parafoveal fixation was much better than that of paramacular fixation and peripheral fixation (P < 0.005). The curative efficiency of amblyopia was also dependent on the degree of amblyopia (P < 0.005). Curative effects of ametropic and anisometropic amblyopia were better than that of strabismic and deprivable amblyopia (P < 0.01). Visual acuity predicted by IVA before the treatment was the same as real results after the treatment in 112 eyes among 125 eyes (92.8%). The correlation efficient between the predicted and real vision was statistically significant (r = 0.886 2, P < 0.000 1).

Vision in most teenage and adult amblyopia can be improved by amblyopic therapy. Therefore, it seems that human visual plasticity exists permanently during the whole life. Visual acuity after the treatment can be predicted by pre-treatment IVA. Results of amblyopia treatment are closely related with the degree and patterns of amblyopia and are also dependent on the cooperation of the patients.