Corneal hyperalgesia in patients with short tear film break-up time dry eye.

Purpose: To evaluate corneal tactile and pain sensations in patients with short tear film break-up time dry eye (sBUT DE).

Methods: This study enrolled 60 patients with sBUT DE and 46 healthy volunteers from Japan. We evaluated corneal tactile and pain sensations using a modified method with the Cochet-Bonnet corneal esthesiometer.

Results: Patients with sBUT DE had higher corneal pain sensitivity (26.3 ± 23.1 mm) than healthy subjects (6.9 ± 16.4 mm), but similar corneal tactile sensation (52.0 ± 15.5 mm and 52.9 ± 14.9 mm, respectively). In patients with sBUT DE and corneal hyperalgesia (n = 22, 36.7%), defined as a pain sensitivity ≥40 mm (i.e., the cutoff value at the 95th percentile of corneal pain sensitivity in healthy subjects), a strong significant correlation was found between the subjective pain score and objective corneal pain sensation (R = 0.79). However, for the entire cohort, we found a weak positive correlation between the subjective pain score and objective corneal pain sensation.

Conclusions: Patients with sBUT DE were hypersensitive to corneal pain, which suggested that corneal hyperalgesia partly accounted for subjective symptoms in patients with sBUT DE.