The effect of phenylephrine on pain and flare intensity in eyes with uveitis

Purpose: To investigate the influence of protein concentration in the anter ior chamber, measured by laser flare meter, on pain sensation after phenyle phrine instillation in patients with iridocyclitis. Methods: Twenty-five co nsecutive patients with iridocyclitis were included. Patients with cataract , exfoliation syndrome, diabetes mellitus, glaucoma or any other previous o cular diseases or ocular surgery were excluded. Patients were divided into two groups: Group 1 - without fibrinoid reaction (FR) in the anterior chamb er (18 patients), and Group 2 - with FR (7 patients). Protein concentration in the anterior chamber was measured with laser flare meter (FC 500, Kowa Co., Japan). Pupil size was measured by Alcon Tilo Scale, and pain sensatio n was estimated by Visual Analogue Scale (VAS, Kabi Pharmacia). All measure ments were done before and 1 hour after topical instillation of 10% phenyle phrine hydrochloride into the subconjunctival sac of the inflammed eyes. Re sults: Eyes with iridocyclitis and fibrinoid reaction (FR) have a higher fl are intensity compared to those without FR (p < 0.05). Pupil size was signi ficantly increased after phenylephrine instillation in both study groups (W ilcoxon test, p < 0.05). The VAS pain and flare intensity were significantl y decreased in group without FR after phenylephrine instillation (Group 1) compared to values before treatment (Wilcoxon test, p < 0.05). In eyes with FR (Group 2), no significant influence of phenylephrine instillation was f ound on VAS pain and flare intensity, Conclusions: After phenylephrine inst illation, flare intensity and pain were significantly decreased only in eye s with iridocyclitis and without FR. The decreasing level of flare intensit y, and paralysis of the pupil after phenylephrine instillation seem to alle viate pain in those eyes.