Purchase this article with an account.
T. Simpson, T. Sin, J. Tang; Bulbar Conjunctival Redness Changes Induced by Mechanical, Chemical and Cooling Corneal Stimuli Presented Using a Belmonte Esthesiometer. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5402.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To determine the change in bulbar conjunctival redness induced by cooling, mechanical and chemical pneumatic stimuli.
20 control subjects had corneal thresholds estimated using a computerised Belmonte pneumatic esthesiometer with cooling (20ºC detection), mechanical (50ºC detection) and chemical stimuli (% CO2 in mixture) using the ascending method of limits. On a randomly selected eye, threshold and supra-threshold (33%, 66% and 100%) stimuli were systematically applied to the central cornea (in random order) and bulbar redness was measured using a Spectrascan spectroradiometer (with controlled illumination) on the side ipsilateral and contralateral to the stimuli each minute after stimulation for 12 minutes.
There was statistically greater redness in the ipsilateral eye (p=0.04), immediately after stimulation (p<0.001) and after the most suprathreshold stimuli (p=0.04). The interaction between stimulus intensity and stimulated eye was also significant (p<0.001) as was the interaction between dose and time (p<0.001). Finally, the 3 way interaction between stimulated eye, intensity and time was significant (p<0.001). Generally, the greater the intensity the greater the redness induced and the longer the duration of redness induced, although this only occurred after the highest stimulus intensity with the room temperature stimulus.
The results illustrate the utility of the Belmonte esthesiometer in examining not just sensory thresholds. Painful mechanical and chemical corneal stimulation induce transient changes (dilation) in local, ipsilateral bulbar conjunctival vasculature and not typically in the contralateral eye. Room temperature stimulation affects redness only at the highest (uncomfortable) levels.
This PDF is available to Subscribers Only