title: A new approach to the study of aqueous humor dynamics by measuring the intensity of Tyndall's effect.
abstract: A technique is described for studying aqueous humor dynamics by measuring aqueous flare intensity with the laser flare-cell meter. Aqueous flare intensity measured with this instrument was converted into the equivalent human albumin concentration (Ca). A differential equation was given to express the relationship among Ca, aqueous flow rate, plasma protein concentration, anterior chamber volume and the coefficient of entry into the anterior chamber (k(in)) for plasma protein. When k(in) is constant, the time course of changes in aqueous flow rate can be determined from a series of measurements of Ca with the laser flare-cell meter. Using this technique, we assessed the effects of oral acetazolamide on aqueous flow rate. Oral administration of 500 mg acetazolamide decreased aqueous flow rate from 1.25 to 8 hours post-administration, with a maximum reduction of 40% at 1.75 hours post-administration. The validity of this technique was confirmed by comparing the results with those of fluorophotometric measurements. In situations where k(in) is affected by ocular procedures, the time course of changes in k(in) can be monitored by measuring Ca, aqueous flow rate and anterior chamber volume in the same eye. We applied this method to investigate the effects of pilocarpine on the rate of protein entry into the aqueous humor. Single instillation of 1% pilocarpine increased k(in) from 4 to more than 10 hours after the application, with a maximum increase of 37% observed at 9 hours post-application.
authors.affiliation: Department of Ophthalmology, University of Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Oshika
authors.forename: M
authors.initials: M
authors.lastname: Mori
authors.forename: M
authors.initials: M
authors.lastname: Araie
mesh_terms: D000086:Acetazolamide / Q000494:pharmacology; D001082:Aqueous Humor / Q000737:chemistry / Q000502:physiology*; D015590:Fluorophotometry; D006801:Humans; D007834:Lasers; D008722:Methods; D010862:Pilocarpine / Q000494:pharmacology; D011506:Proteins / Q000032:analysis
chemical_list: D011506:Proteins; D010862:Pilocarpine; D000086:Acetazolamide