Validation and Comparative Analysis of a Contemporary Non-Contact Corneal Aesthesiometer

Background: Corneal sensitivity is a key indicator of ocular surface health. This prospective, cross-sectional study evaluated agreement between corneal sensitivity thresholds obtained from equivalent stimulus settings on a contemporary, enhanced dual-temperature non-contact corneal aesthesiometer (NCCA) and a previously validated (standard) device. Methods: Central corneal sensitivity thresholds were measured in the right eyes of healthy participants using both devices. Participants with previous ocular surgery, laser treatment, trauma, contact lens wear, diabetes, or peripheral neuropathy were excluded. Sensitivity thresholds were determined using a forced-response, double-staircase protocol. Inter-device agreement was assessed using Bland-Altman analysis, and consistency was assessed using intraclass correlation coefficients. Results: Median corneal sensitivity thresholds in 51 healthy participants (32 female, 19 male; mean age: 33 ± 14 years) did not differ between enhanced (0.23 [0.18 to 0.38]) and standard (0.25 [0.15 to 0.35]) NCCA instruments (p = 0.73). Bland-Altman analysis demonstrated moderate inter-device agreement, with a mean difference of -0.01 mbar (95% limits of agreement: -0.41 to 0.39 mbar). Linear regression analysis identified greater measurement discrepancies at higher thresholds (p < 0.05), indicating greater variability in individuals with reduced corneal sensitivity. Conclusions: The enhanced NCCA yields reliable corneal sensitivity measures for a room-temperature stimulus and acceptable agreement with the existing (standard) model.