Abstract
Purpose :
We have analyzed corneal sensitivity with a gas esthesiometer, corneal surface temperature, blink frequency, tearing rate and TBUT in young contact lens wearers (CLWs) with and without ocular surface discomfort symptoms, and in eye glasses wearers (EGWs).
Methods :
Young subjects (18-40 years old) of both sexes participated voluntarily. CLWs were divided in asymptomatic (CLW-A) and symptomatic (CLW-S) subjects depending on their OSDI score (<13 and ≥13, respectively). Mechanical and chemical corneal sensitivity (explored with the Belmonte-CRCERT gas esthesiometer; 3s-duration gas jets at 0-200 ml/min flow, 0-80% CO2; sensation scored in a 0-10 VAS), corneal surface temperature (CST; explored using an IR video camera), spontaneous and attentional (visual task) blinking frequency, tearing rate (phenol red threads, 15s) and TBUT were measured. EGWs with similar refractive errors that never wore CL served as control.
Results :
Irritation VAS values evoked by mechanical and chemical stimulation measured 5 min after CL removal were higher in CLW than in EGW wearers (p<0.05), although no differences between CLW-A and CLW-S were found (see Table). CST was lower in CLW than in EGW, although with higher values in CLW-S group (see table). Both spontaneous and attentional blinking frequency were higher in CLWs, reaching significant differences in CLW-S (see Table). Tearing rate was similar in all three groups, although TBUT was significantly shorter in CLW-S group (see Table).
Conclusions :
CL wearing produce in some subjects symptoms of ocular discomfort that could be consecutive to tissue inflammation, tear instability and corneal sensory nerve damage. Altered firing of corneal nerves lead to an increase in spontaneous and stimulus-evoked irritation sensation, and increase blink frequency.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.