The relationship between bulbar conjunctival hyperemia and temperature was investigated. Conjunctival redness was induced in eighteen volunteers by instilling hypertonic saline into the conjunctival sac. The degree of redness was estimated using a subjective grading scale. The subsequent changes in temperature of the nasal bulbar conjunctiva were monitored using an infra-red bolometer. Conjunctival hyperemia was significantly correlated with conjunctival temperature; the maximum response of a 3-grade change in redness was accompanied by an increase of 0.5°C in temperature. These findings confirm the classic association between inflammation, rubor and calor.