Related Experiment Video
Updated: Jul 13, 2026
Corneal Sensitivity Testing Procedure for Ophthalmologic and Optometric Patients
Published on: August 2, 2024
Noncontact Esthesiometer: Large Cohort Study on Agreement with Contact Method and Correlations with Corneal Nerves
Mingyi Yu1, Chang Liu1, Isabelle Xin Yu Lee1
1Regenerative Therapy Group, Singapore Eye Research Institute, Singapore, Singapore.
Purpose:
To evaluate the repeatability of noncontact Brill esthesiometer (NBE), its agreement with Cochet-Bonnet esthesiometer (CBE), and the relationship between corneal sensitivity, corneal nerve metrics, and ocular surface parameters.
Design:
Cross-sectional study.
Subjects:
This study included 880 eyes, comprising healthy controls (80 eyes), dry eye disease (DED) (170 eyes), neuropathic corneal pain (NCP) (140 eyes), postrefractive surgery (P-RS) (176 eyes), and diabetes mellitus (DM) (314 eyes).
Methods:
Noncontact Brill esthesiometer and CBE measurements were obtained at central and 4 peripheral corneal quadrants. Both measurements were converted to millinewtons (mN) for analysis. In vivo confocal microscopy for 7 corneal nerve parameters and 4 ocular surface parameters were assessed.
Main Outcome Measures:
Agreement between NBE and CBE measurements. Correlations between NBE measurements, corneal nerve metrics, and ocular surface characteristics.
Results:
Noncontact Brill esthesiometer presented excellent intraobserver and interobserver repeatability with both intraclass correlation coefficients >0.980 (P < 0.001). Noncontact Brill esthesiometer showed significantly higher values in mN than CBE (all P < 0.001). Noncontact Brill esthesiometer and CBE measurements showed good agreement in eyes with better corneal sensitivity (NBE <0.085 mN), whereas the agreement decreased at higher values. Noncontact Brill esthesiometer and CBE measurements significantly correlated across all cohorts (all P < 0.05). Postrefractive surgery group had the highest proportion of eyes within 95% limits of agreement (98.3%) and the strongest correlation between NBE and CBE measurements (r = 0.853, P < 0.001). Noncontact Brill esthesiometer measurements significantly correlated with corneal nerve parameters in the control, DED, P-RS, and DM groups (r = -0.219 to -0.545), while CBE showed significant correlations only in the DED and P-RS groups with comparable magnitude (r = -0.251 to -0.554, all P < 0.05). The strongest significant correlations for both NBE and CBE were in P-RS group (NBE: r = -0.514 to -0.545; CBE: r = -0.554). After adjustment for confounders, NBE was significantly associated with corneal nerve fiber length and width, while CBE showed significant association only with corneal nerve fiber fractal dimension. Noncontact Brill esthesiometer measurements, to a greater extent than CBE, significantly correlated with ocular surface parameters in the control, NCP, and DM groups (r = -0.126 to -0.465, all P < 0.05).
Conclusions:
Noncontact Brill esthesiometer and CBE measurements showed good agreement at better corneal sensitivity and are not interchangeable. Noncontact Brill esthesiometer might link better with corneal nerve and ocular surface changes compared with CBE.
Financial Disclosures:
The author has no/the authors have no proprietary or commercial interest in any materials discussed in this article.
