Functioning and Safety of the Non-Invasive Corneal Esthesiometer Brill: A Multicenter Study

Background/Objectives: Corneal sensitivity can be decreased by several ocular conditions, including dry eye and refractive surgery, which can lead to ocular epithelial lesions. This decrease can be detected by esthesiometry. The main objective of this study was to evaluate the performance, safety, and efficacy of the Corneal Esthesiometer Brill in healthy subjects without ocular pathologies. Methods: A controlled, randomized, prospective, multicenter pilot clinical study was conducted in adult patients with healthy eyes. Corneal sensitivity measurements were made three times for one eye randomly selected to obtain the corneal sensitivity reference ranges. Additionally, one more measurement was taken after the application of a topical anesthetic. An intra- and inter-observer analysis was performed to assess user dependence, and the last measurement was taken after ocular topical anesthesia to evaluate the device's sensitivity in detecting corneal sensitivity loss. Results: Ninety-one volunteers were included with a mean age of 25 (SD 3.46, range 18-30), and fifty-eight (63.7%) were female. Corneal sensitivity reference levels ranged from level 2 (3-4 mbar) to level 3 (4-5 mbar). Intra- and inter-observer measurement differences on the same subject without anesthesia were not statistically significant. Corneal pressure before and after local ocular anesthesia had statistically significant differences (p < 0.0001). Conclusions: The Corneal Esthesiometer Brill yielded consistent and reproducible measurements in young volunteers with healthy eyes, enabling objective, observer-independent use and facilitating the detection of significant loss of sensitivity.