In a recent editorial that accompanied our September 1997 article1 on the use of botulinum toxin for management of infantile esotropia, Kushner2 raised 2 major criticisms concerning the patient population and the number of procedures that are required to achieve a satisfactory outcome. Dr Kushner2 has challenged the inclusion of patients whose deviation is less than the 30 prism diopters (PD) esotropia that he regards as the typical minimum angle of infantile esotropia. In reviewing the literature in this field,3 however, no uniform minimum and maximum limits of strabismic angle exist. In the studies cited by Kushner, Von Noorden4 includes infantile esotropia patients with deviations ranging from 5 to 100 PD, while 21% of the patients in the study by Costenbader5 have deviations less than 24 PD. More recently, Helveston6 indicated that deviations of 10 to 90 PD are characteristic of infantile esotropia. Kushner further suggests the "Inadvertent inclusion of patients with acquired esotropia,"2(p1458) even though all of the patients in our study manifested a deviation prior to 6 months of age (as opposed to the more typical onset of acquired esotropia after 24 to 30 months of age) that was present at both near and distance fixation. The possibility of "selection bias" is refuted by noting that our patient population is consecutive, and through the process of informed consent, all of the parents elected the botulinum toxin procedure instead of incisional surgery.
McNeer KW, Tucker MG, Spencer RF. Botulinum Toxin Therapy for Essential Infantile Esotropia in Children. Arch Ophthalmol. 1998;116(5):701-703. doi: