Conjunctival provocation test: high clinical reproducibility but little local temperature change

Ten atopic and five healthy individuals participated in eight conjunctival provocation tests (CPT) in an effort to improve the CPT procedure. Results were evaluated by thermography and the use of conventional criteria under various conditions. Due to considerable spontaneous variability and change in temperature already after instillation of diluent, thermography was not sensitive enough to identify positive CPT results. The precision of the CPT was within one 10-log step in all tests and in all patients. Itching appeared before erythema in 83% of subjects and within 5-8 min after instillation of the allergen. This was true also when only one eye was used for the CPT. We therefore conclude that the CPT procedure can be used in one eye every 5-8 min when indicated in clinical routine and that it is a safe, precise method.