To the Editor.
—We read with great interest the article on prism adaptation in acquired esotropia by the Prism Adaptation Study Research Group1 and would like to congratulate the research group on their report. The most outstanding feature of their article was that a classification system was agreed upon that distinguished orthotropic cases from cases of slight manifest deviation of up to 8 prism diopters developing 6 months after surgery. The criterion used until now of "8 Δ within the limits of orthophoria" has been useless in distinguishing between orthotropic and microtropic cases.On reading the article, we wondered whether there was a difference in age at onset between the different groups. In fact, in the group who underwent prism adaptation and surgery based on entry angle of esotropia, the median age at onset was 30.5 months (n=67; orthotropia was accomplished in 32% of patients); in the group who
Lang J, Heinrich T. Prism Adaptation in Acquired Esotropia. Arch Ophthalmol. 1992;110(6):751-752. doi:10.1001/archopht.1992.01080180021008