Temporal Effects of 2% Pilocarpine Ophthalmic Solution on Human Pupil Size and Accommodation

Abstract

Introduction First responders and those who work with organophosphate (OP) compounds can experience ocular symptoms similar to those caused by exposure to low levels of nerve agents. This study was designed to examine the efficacy of a safe, clinically available, simulant that reproduces ocular symptoms associated with low-level OP exposure. Among these ocular symptoms are a constriction of the pupils (miosis), decreased visual acuity, and changes in accommodation. Materials and Methods Volunteers aged 18–40 were assigned to groups receiving either a two-drop or three-drop dose of FDA approved 2% pilocarpine ophthalmic solution. Baseline visual performance measurements were taken before eye drop instillation and a timer was started following the first drop of pilocarpine. Once eye drops were administered, visual performance including distant and near vision, pupil size, and accommodation were measured every 5 minutes for 2 hours. Results Both groups experienced significant miosis in excess of 90 minutes. Visual acuity was significantly reduced because of accommodative changes. The three-drop group experienced longer lasting combined effects when compared to the two-drop group. Conclusions 2% pilocarpine ophthalmic solution can safely simulate major ocular symptoms of OP exposure for behavioral research studies for at least 60 minutes.

Influence of Pilocarpine Eyedrops on the Ocular Biometric Parameters and Intraocular Lens Power Calculation

“…About 2 mm pupil diameter efect has been demonstrated in human using a 2% ophthalmic pilocarpine solution for longer than an hour [22]. In our study, ophthalmic pilocarpine administration induced a signifcant decrease in pupil diameter both in PACG patients and normal subjects.…”

“…Pupillary constriction was achieved with the topical application of 2% pilocarpine nitrate eyedrops (Freda Pharmaceutical, Shandong, China) at 15 min intervals. After 30-45 minutes, ocular biometric measurements were taken because the efect of pilocarpine on the ciliary muscle works maximally in 30 minutes to 60 minutes without IOP fuctuation [20][21][22].…”

Current situation and progress of drugs for reducing intraocular pressure

“…Cholinergic drugs 12 Increasing AH outflow through the TM Pupil narrowing, pseudomyopia, retinal detachment, night vision loss, headache, conjunctival hyperaemia; gastrointestinal disturbances, excessive salivation and sweating, slow heartbeat A pre-treatment for laser glaucoma and in the treatment of acute angleclosure glaucoma.…”

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“…16,17 Cholinergic agonists (eg Pilocarpine) increase conventional aqueous outflow, however are less commonly used than other classes due to their poorly tolerated side effect profile, including myopic shift, nyctalopia, and increased risk of retinal tears and detachment. [18][19][20][21][22]…”