In spite of continued daily or twice daily topical anticholinesterase (ChE) application (isoflurophate [diisopropyl fluorophosphate] or echothiophate iodide), the pupils of monkey eyes redilate to near normal size by the fifth day of the chronic cholinesterase inhibitor treatment. The light reflexes appear to be unaffected even after weeks of isoflurophate treatment, but the irides of these eyes become unreactive to normal doses of pilocarpine hydrochloride or carbachol. There was no evidence that topically applied pilocarpine interferes with the light reaction in either the normal or the anti-ChE-pretreated monkey eye. After termination of the chronic isoflurophate treatment the pilocarpine insensitivity is maintained for at least three days, and normal sensitivity to pilocarpine does not completely return within seven days of the last isoflurophate treatment.
Bito LZ, Banks N. Effects of Chronic Cholinesterase Inhibitor TreatmentI: The Pharmacological and Physiological Behavior of the Anti-ChE-Treated Monkey (Macaca mulatta) Iris. Arch Ophthalmol. 1969;82(5):681-686. doi:10.1001/archopht.1969.00990020675017