The sensitive period: transfer of fixation after occlusion for strabismic amblyopia.

Of 2649 patients with strabismic amblyopia who attended clinics between 1941 and 1978, 1904 patients were reviewed. Of these, 115 patients had transfer of fixation after occlusion. These were analysed according to the type of transfer of fixation and relation to occlusion and age. The period of maximum sensitivity to short periods of occlusion extended to 18 months, declining to about 30 months of age. Sensitivity to occlusion reaches low levels about the age of 5 to 51/2 years, though it is still present to some degree, especially in patients with relatively good visual acuity of 6/36 or better. The upper limit of the sensitive period was found to be about the end of the seventh year of age.