[Aqueous flare and cells after mydriasis in normal human eyes]

The influence of mydriasis on aqueous flare intensity and cell number was investigated in normal human eyes. A mixture of 0.5% phenylephrine and 0.5% tropicamide (Mydrin P) was topically instilled in 173 eyes of normal subjects ranging from 20 to 79 years old, and measurements with a laser flare-cell meter were carried out before and 1 hour after the application. For statistical analysis, subjects were divided into groups based on ten-year age intervals ranging from 20-29 years to 70-79 years. Aqueous flare intensity was significantly decreased by mydriasis in all age groups. Prior to drug application, aqueous cells were observed in none of the cases, while after mydriasis, apparent aqueous floaters appeared in 9.2% of the cases, all of whom were over 40 years of age. Appearance of aqueous floaters following mydriasis was not accompanied by an increase in aqueous flare intensity. Time course of changes in aqueous flare intensity after topical instillation of 5% phenylephrine and 0.4% tropicamide were investigated separately. Tropicamide decreased aqueous flare intensity in normal young human subjects, and values at 1 and 1.5 hours post-application differed significantly from those of the contralateral control eyes. The instillation of phenylephrine in normal young subjects resulted in a significant decrease of aqueous flare at 3 hours post-application. Observed decreases in aqueous flare intensity by a commonly used mydriatic agent, a combined solution of phenylephrine and tropicamide, was considered to be the result of the pharmacological effects of tropicamide.