RELIABILITY OF DIAGNOSTIC-TESTS FOR CONTACT ALLERGY TO MYDRIATIC EYEDROPS

Adverse reactions due to the administration of mydriatic eyedrops are not uncommon. In Spain, the most commonly used are phenylephrine, trop icamide and cyclopentolate hydrochloride. In this study, 37 patients w ith adverse reactions to the administration of mydriatic eyedrops were investigated from January 1993 to June 1997. The aim was to assess th e reliability of the diagnostic methods used, particularly the adequat e concentration of allergens and the introduction of conjunctival chal lenge as a safe and accurate diagnostic tool in those patients who cou ld not be diagnosed by other methods. Phenylephrine was the drug most frequently causing sensitization (93.5%) among the 31 allergic patient s. Preservatives were the cause in only 1. Patch testing detected alle rgy in 68.5% of the subjects. 2 concentrations (1% and 10%) and vehicl es (pet. and aq.) were used for phenylephrine. The most reliable was 1 0% aq. Reading at D4 was more useful than at D2. The sensitivity of th e patch test was low (72.4%) and its negative predictive value (NPV) p oor (42%). In 24% of patients, allergy to phenylephrine was detected o nly by conjunctival challenge test. This diagnostic method is safe and helpful and has not previously been used to diagnose adverse reaction s due to mydriatic eyedrops. (C) Munksgaard, 1998.