Abstract
Abstract: :
Purpose: To investigate how corneal and conjunctival mechanical sensory channels respond to toric soft contact lens wear. Methods: 48 non–contact lens wearing healthy subjects (M=17, F=31) participated in this study. Central corneal and inferior conjunctival mechanical sensitivities of both eyes were measured at baseline (without contact lens wear) and after wearing lens for one, three, six hours and one and two weeks. A Belmonte pneumatic esthesiometer was used to deliver stimuli at ocular surface temperature. The ascending method of limits was used to estimate the threshold. Results: At each time point during this experiment, corneal mechanical sensitivity was higher than that of the conjunctiva. There was no difference in both corneal and conjunctival sensitivities between eyes. After one, three, and six hours wearing of contact lenses, corneal and conjunctival mechanical sensitivities increased. Repeated measures ANOVA showed a main effect of time on corneal sensitivity (F(5,235) = 5.362, p = 0.000) and conjunctival sensitivity (F(5,235) = 4.752, p = 0.000). Both corneal and conjunctival sensitivities gradually returned to baseline level by two weeks. Conclusions: This study showed that corneal and conjunctival sensory channels respond to contact lens wear with an initial transient increase in corneal and conjunctival mechanical sensitivity before adapting to contact lens wear. It suggests that the ocular surface sensory system response to contact lens wear is more complex than simple adaptation.
Keywords: innervation: sensation • contact lens • cornea: clinical science