Reproducibility and Safety of Corneal Sensitivity Evaluation With Belmonte's Esthesiometer

Abstract

 

Purpose:

 

The purpose of this study is to establish the mechanical (TM), chemical (TCh), thermal hot (TTH) and thermal cold (TTC) sensitivity thresholds of corneal sensitivity (CS) in healthy men and women of different age groups with a gas esthesiometer (Belmonte’s esthesiometer), and to analyze the reproducibility and safety of the technique.

 

Methods:

 

TM, TCh, TTH and TTC were determined in 80 eyes of 40 healthy subjects (40 males, 40 females) equally distributed in number and gender in 5 age ranges (20-29; 30-39; 40-49; 50-59; >60 years of age). CS was measured with the Belmonte’s esthesiometer in the central cornea. Thresholds were determined using the method of levels. TM was determined first, and the order in which TCh, TTH and TTC were measured was randomly assigned for each subject, as well as the starting eye. To evaluate reproducibility, CS was measured for each eye in two different days (interval, 1-6days), both measures were taken between 16:00 and 20:00 hours. To evaluate the safety of the technique, changes in corneal fluorescein staining and bulbar hyperemia were analyzed before and after.

 

Results:

 

Table 1 shows the four sensitivity thresholds (mean ± SEM) during the 1^st and 2^nd evaluation, in addition to their respective reproducibility indexes: difference of mean ± standard error of the mean (DM ± SEM), intraclass correlation coefficient (ICC) and 95% confidence interval (CI).CS had similar values regardless of gender and age. These values did not vary in two different time points. The use of the gas eshesiometer was safe and reproducible. TM and TTH reproducibility was higher than TCh and TTC.  

 

Conclusions:

 

Sensitivity thresholds in central cornea with four different stimuli (mechanical, chemical, hot and cold thermal) yielded similar values in healthy males and females at different age ranges. The use of gas esthesiometry was safe and reproducible.

 

Keywords: innervation: sensation • cornea: clinical science • clinical (human) or epidemiologic studies: systems/equipment/techniques