Characterization of Sensation in Patients with Accepted Corneal Penetrating Keratoplasty Using a Non-Contact Esthesiometer

Abstract

Purpose : To characterize corneal sensitivity in corneal transplants of recipient patients with accepted corneal penetrating keratoplasty (PK) using the Brill non-contact esthesiometer (BNCE) and the Cochet-Bonnet esthesiometer (CBE).

Methods : This cross-sectional, descriptive study included patients with a history of an accepted PK from the Foster Eye Center for Ocular Immunology at the Duke Eye Center. Corneal sensitivity was evaluated in both eyes using the BNCE per the manufacturer’s instructions and the CBE. The minimal sensitivity threshold (mBar) at which the patients perceived the BNCE air-jet stimulus was recorded in addition to the CBE monofilament length (mm) at which they detected the stimulus. Additional clinical measurements included corneal and conjunctival staining using the National Eye Institute (NEI) scale, Schirmer’s 1, the Ocular Surface Disease Index (OSDI) questionnaire, and the time elapsed since the last PK in months. Unpaired t-tests were used to compare the averages between PK and control eyes, with a p-value <0.05 considered statistically significant.

Results : 34 eyes (24 PK, 10 controls) from 20 patients (55% female) were included in the study. All patients underwent a comprehensive ophthalmologic examination. The mean time from PK was 33.55 +/- 60.76 months. The corneal sensitivity readings followed a similar trend between both devices. The average minimum BNCE threshold was 4.2 and 2.7 mBar (p = 0.039), while the average CBE was 43.3 vs. 53 mm (p = 0.0282) for the PK and control groups. Corneal NEI staining scores were 4.75 and 2.0 (p > 0.05), and conjunctival NEI scores were 0.33 and 0.55 (p > 0.05) for PK vs. non-PK. The mean OSDI score was 25.95 +/- 19.67.

Conclusions : Corneal sensitivity is generally reduced in accepted PK eyes compared to non-PK eyes, maintaining a clear and healthy transplant. This trend is observed using both esthesiometers, and the BNCE is a reliable tool for evaluating corneal sensitivity after PK. Moreover, the non-contact nature of the BNCE provides safety advantages that are particularly relevant in the care of post-surgical patients. Longitudinal studies are needed to determine how monitoring of corneal sensation after PK using the BNCE relates to graft acceptance vs. rejection.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.