Comparison of conventional, non-conventional (inverse), and red-filter occlusion

Occlusion of the sound eye (conventional occlusion) introduced by Buffon (I 743) was the only treatment for amblyopia until Bangerter (I953) introduced occlusion of the amblyopic eye (non-conventional or inverse occlusion) combined with pleoptic treatment in cases of amblyopia with eccentric fixation. Mackensen, Kroner, and Postic (I965), von Noorden (I965), Posti6 (I966), Borgmann and Dielefeld (I967), and Ver Lee and Iacobucci (I967) found conventional occlusion of the sound eye to be as good as pleoptic treatment. On the other hand, Arruga (I962) and Cibis and Windsor (I967) favoured non-conventional (inverse) occlusion of the amblyopic eye. Brinker and Katz (I963) introduced red-filter occlusion to avoid the shortcomings of pleoptic treatment. Because of the disparity in the results given by various authors, the present study was undertaken to provide comparative data and to ascertain the significance of such factors as age of patient, fixation pattern, refractive error, and strabismus in the response to occlusion therapy. This study includes a number of patients above the age of I 2 yearsa group not discussed by other workers.