Relationship between Ocular Surface Temperature and Peripheral Vasoconstriction

Abstract

The aim of the present study is to verify whether a peripheral vasoconstriction is related to a change of the eye blood perfusion. This feature is indirectly evaluated measuring the variations of the ocular surface temperature (OST) by infrared thermography. For the experimental tests 45 healthy young subjects (mean age 25.4± 4.1 years) were enrolled, 35 men and 10 women. The test is repeated two times for each subject, with a 30 minutes spacing. Each acquisition is 40 s long, during which the subject immerses the hands in a tank with ice and water (1.6°±0.4°). In a single test the OST is registered during the first 10 s and during the last 10 s. Between the two registrations the subject maintains the eyes closed. So, the OST acquired at the beginning and at the end of the test were compared by a paired T − test. The data show a significantly OST increase (p<0.05), especially in the ocular surface areas near to principal sclera arteries, i.e. temporal and nasal areas (average increasing +0.13°): so, there is a response of the eye blood flow to the peripheral vasoconstriction (if the temperature increases we assert that also the flow blood increase). In fact, the organism in hypothermic conditions limits the heat dissipation and so, the blood flow in the areas more exposed to the external environment decreases. Consequently the blood flow increases in districts that guarantee the survival of the subject. The eye, which is perfused by the same vessel networks that lead blood to the central nervous system undergo to an increment of blood flow. Then, the comprehension of relationships between vasoconstriction and eye perfusion in healthy may be important in the study of some ocular pathologies in which the vasoconstriction is an important factor in their etiopathogenesis.