Variations in refractive change induced by Cyclogyl upon children with differing degrees of ametropia.

The effect of cycloplegic drugs on refraction is complicated by the presence of many variables. This study is concerned with one of these: the type and degree of refractive error. A manifest and a cycloplegic refraction were performed on 170 eyes. The difference was determined in each case and tabulated according to the type of ametropia. This experiment showed that in every instance the cycloplegic estimate was equal to or greater in hyperopia or less in myopia than when performed without drugs. The greatest difference occurred in hyperopia, decreasing to zero once myopia was reached.