THE EFFECT OF SINGLE-APPLICATION TOPICAL OPHTHALMIC ANESTHESIA IN PATIENTS WITH TRIGEMINAL NEURALGIA - A RANDOMIZED DOUBLE-BLIND PLACEBO-CONTROLLED TRIAL

To evaluate the reported benefit of ipsilateral single-application oph thalmic anesthetic eyedrops in patients with typical trigeminal neural gia, a randomized double-blind placebo-controlled trial was performed. Forty-seven patients were randomly assigned to receive two drops of e ither proparacaine (25 cases) or saline placebo (22 cases). The experi mental and placebo groups were equivalent in regard to patient age, di stribution of trigeminal neuralgia pain, duration of pain, current med ication regimens, and number of prior procedures performed. Pain respo nse was assessed at 3, 10, and 30 days after instillation using two pa in rating scales and a measure of pain frequency. Treatment failure wa s defined in advance as any of the following: a lack of clinical respo nse, the need for an increase in medication, or the need for surgery. No significant difference in outcomes was found between the two groups either when using a verbal pain rating scale (p = 0.24) or when compa ring overall pain status (unchanged, improved throughout the study per iod, or temporarily improved) (p = 0.98). No difference in the frequen cy of trigeminal neuralgia attacks between the two treatment groups (s caled within five levels of pain frequency) was detected (p = 0.09). D uring follow-up monitoring, 11 patients in the test drug group and 14 in the placebo group required surgery because of persistent pain (p = 0.24). The results of this study indicate that single-application topi cal ophthalmic anesthesia reduces neither the severity nor the frequen cy of pain in comparison to placebo administration. Although a simple and safe treatment, the single application of topical ophthalmic eyedr ops provides no short- or long-term benefit to patients with trigemina l neuralgia.