Conjunctival and corneal hyperesthesia in subjects with dryness symptoms

To compare conjunctival and corneal sensitivity in noncontact lens wearing subjects with and without symptoms of ocular dryness, stratified by age and gender.

Ninety-seven subjects were enrolled, 54 of whom were asymptomatic and 43 of whom were symptomatic of ocular dryness. A single score for the symptom of dryness was used to classify nondry eye (scores of none to trace) and dry eye symptomatic (scores of mild to severe) groups. The subjects were further stratified into "younger" (19 to 49 years) and "older" age groups (50 to 80 years). Conjunctival and corneal sensitivity of the right eye was measured at the central cornea and temporal conjunctiva, using a computer-controlled pneumatic esthesiometer with stimulus temperature set at 20 degrees C. The ascending method of limits was used to determine the thresholds.

Conjunctival and corneal thresholds were significantly lower in the dry eye symptomatic than in the nondry eye group (both p < 0.01). The conjunctival threshold was lower than the corneal threshold in the dry eye symptomatic group (p < 0.01) but not in the nondry eye group (p > 0.05). Conjunctival threshold in the nondry eye women was lower than the men (p < 0.05). No difference between age groups was found for conjunctival and corneal thresholds in this study (all p > 0.05).

Conjunctival and corneal sensitivity to pneumatic cool stimulation is increased in subjects with symptoms of ocular dryness. This hyperesthesia seems to be more significant in the conjunctiva.