Comparative Evaluation of the Corneal Sensitivity Thresholds between the Novel Non-Contact and Cochet-Bonnet Esthesiometers

Raul E Ruiz-Lozano; Manuel E Quiroga-Garza; Eugenia M Ramos-Dávila; Jezreel Pantaleón García; Ali Khodor; Seitaro Komai; Luis A Rodriguez-Gutierrez; Symon Ma; Hazem M Mousa; Robby Mattes; Sandra S Stinnett; Alfonso L Sabater; Victor L Perez

doi:10.1016/j.ajo.2024.12.013

Comparative Evaluation of the Corneal Sensitivity Thresholds between the Novel Non-Contact and Cochet-Bonnet Esthesiometers

Am J Ophthalmol. 2024 Dec 17:S0002-9394(24)00570-1. doi: 10.1016/j.ajo.2024.12.013. Online ahead of print.

Affiliations

¹ Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; Tecnologico de Monterrey, School of Medicine and Health Sciences, Institute of Ophthalmology and Visual Sciences, Monterrey, Mexico.
² Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA.
³ Tecnologico de Monterrey, School of Medicine and Health Sciences, Institute of Ophthalmology and Visual Sciences, Monterrey, Mexico.
⁴ Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
⁵ Department of Ophthalmology, Foster Center for Ocular Immunology at Duke Eye Center, Duke University School of Medicine, Durham, North Carolina, USA.
⁶ Associate Professor of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC, USA.
⁷ Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA. Electronic address: vperez4@med.miami.edu.

PMID: 39701509
DOI: 10.1016/j.ajo.2024.12.013

Abstract

Purpose: Primarily, to evaluate the repeatability and reproducibility of the new non-contact esthesiometer (NCE) in healthy subjects. Secondarily, the corneal sensitivity threshold measurements of the NCE were compared with those of the Cochet-Bonnet esthesiometer (CBE).

Design: Assessment reliability study.

Methods: Two examiners measured bilateral corneal sensitivity thresholds by NCE and CBE. Triple NCE measurements were performed per eye at all five levels, whereas single CBE measurements were performed per eye. When appropriate, NCE (mBar) and CBE (mm) measurements were converted to millinewtons (mN) for direct comparison between devices. The NCE measurement variations were calculated with the intra-class correlation coefficients (ICC) for the primary objective. For the secondary objective, Bland-Altman plots with 95% limits of agreement (95%-LoA) and Spearman's rank correlation coefficients were used to evaluate the level of agreement and linear relationship between the corneal sensitivity thresholds obtained with both devices. Generalized estimating equation models were used to account for the inter-eye correlation of the same study participant.

Results: Fifty subjects (100 eyes) aged 29 years (median) were included. There were no statistically significant differences in the pressure measured by both observers at each NCE level (all p > 0.05). There was a high intra-observer and inter-observer repeatability of the NCE measurements (ICC > 0.90) and a strong linear correlation (rho > 0.7) at each NCE level. The difference between the mean corneal sensitivity thresholds (mN) measured with the NCE (0.052 ± 0.021 mN) and CBE (0.046 ± 0.005 mN) was statistically significant (p = 0.001). Bland-Altman analysis revealed a differential bias of +0.00578 mN (95%-LoA -0.03677 - +0.04833 mN) between threshold measurements.

Conclusions: The NCE provides reliable user-independent corneal sensitivity measurements. The NCE and CBE do not yield similar values. Thus, both devices cannot be used interchangeably.

Keywords: Brill; Cochet-Bonnet; corneal nerves; corneal sensitivity; esthesiometer.