A comparative study of Ocuserta® Pilo 40, intensive pilocarpine and low-dose pilocarpine in the initial treatment of primary acute angle-closure glaucoma

Abstract

Acetazolamide and pilocarpine have a central role in the initial management of primary acute angle closure glaucoma (PACG), but there is no consensus concerning their mode of delivery, as borne out by a recent survey of senior UK ophthalmologists reported below. Ocusert Pilo 40 was developed to remain in situ releasing pilocarpine for up to one week. In view of its potential advantages, a trial of Ocusert Pilo 40's efficacy in PACG was conducted. In two separate controlled studies, eyes diagnosed with PACG were randomised to receive Ocusert Pilo 40, and either an intensive pilocarpine regimen or a low-dose pilocarpine treatment. All patients also received Diamox 500 mg i.v. Two hours after starting topical treatment, the study was terminated and ocular and systemic response to treatment and the eventual outcome were assessed. In both studies, intravenous Diamox caused a fall of intraocular pressure (IOP) within 30 min. Over the treatment period, a comparable reduction in IOP was seen in the Ocusert-treated, the intensive-pilocarpine-treated, and the low-dose-pilocarpine-treated groups. No damage to the corneas were observed.

New findings in the diagnosis and treatment of primary angle-closure glaucoma

“…Miotics are likely to constrict the pupil only after IOP has been lowered. When the sphincter is ischemic and the pupil non reactive, the administration of parasympathomimetics will not cause pupillary constriction but may cause the paradoxical effect of forward rotating the ciliary muscle, thereby increasing the pupillary block (Aung et al, 2000;Edwards, 1997;Ganias and Mapstone, 1975).…”

Advancements in ocular drug delivery

“…A biodegradable insert (Ocusert Pilo 40, Alza Corporation, Mountain View, CA, USA) placed in the lower conjunctival sac was designed to release therapeutic levels of pilocarpine for 7 days. 52 Similar inserts have been developed for atropine and gentamicin. 2 Another insert, a hybrid polymeric hydrogel prepared by the reaction of acrylic acid-functionalized chitosan with either N-isopropylacrylamide or 2-hydroxyethyl methacrylate monomers, was demonstrated to enhance the delivery of chloramphenicol, atropine, and norfloxacin in vitro and pilocarpine in vitro and in vivo in a rabbit model.…”

“…Biodegradable ocular inserts can be placed in the lower conjunctival sac for sustained release of drugs. A biodegradable insert (Ocusert Pilo 40, Alza Corporation, Mountain View, CA, USA) placed in the lower conjunctival sac was designed to release therapeutic levels of pilocarpine for 7 days 52 . Similar inserts have been developed for atropine and gentamicin 2 .…”