Is corneal temperature correlated with blood-flow velocity in the ophthalmic artery?

Abstract

PURPOSE. To evaluate the correlation of blood-flow velocities in the ophthalmic artery and corneal temperature in normal subjects and glaucoma patients. METHODS. Corneal temperature was measured on both eyes by means of the THI–500 non-contact infrared thermometer in 18 healthy volunteers and in 18 age and sex matched open-angle glaucoma patients. In these subjects, blood flow velocity was assessed by means of color Doppler imaging (CDI) in both ophthalmic arteries. Peak systolic velocity (PSV), end diastolic velocity (EDV), and resistivity index (RI = [(PSV-EDV)/ PSV]) were computed. RESULTS. Corneal temperature values correlated positively with the ipsilateral values of EDV (R 2 = 0.13, p = 0.028, and R 2 = 0.16, p = 0.017 in the left and the right eyes respectively) and negatively with the ipsilateral values of RI (R 2 = 0.11, p = 0.046 and R 2 = 0.11, p = 0.044 in the left and the right eyes respectively) in the ophthalmic artery. In addition, the interocular difference in corneal temperature values were significantly correlated positively with the difference in EDV(R 2 = 0.30, p = 0.0005) and negatively with the difference in RI (R 2 = 0.20; p: 0.0056). All regression models were statistically comparable between normals and glaucoma patients, as well as between right eyes and left eyes. PSV did not contribute to corneal temperature. CONCLUSIONS. The present study suggests that retrobulbar hemodynamics influence corneal temperature, and that this relationship is comparable in normal subjects and glaucoma patients.