Abstract
Abstract: :
Purpose: Discomfort symptoms commonly accompany several conditions including ocular surface disease, tear film insufficiency and contact lens wear. Due to anecdotal reports that ocular discomfort is perceptually more disturbing when vision is poor, we sought to determine if the perceived magnitude of ocular discomfort depends on visual status. Method:Twenty -one subjects were subjected to varying levels of discomfort in one eye only by wearing each of three contact lens types, soft hydrogel (SH), silicone elastomer (SE) or rigid gas permeable (RGP). At each discomfort level, three visual conditions were imposed by either full refractive correction (FC), full correction with an additional +4DS blur (B) or occlusion (O). For each condition, subjects rated the magnitude of their subjective discomfort using a 1-100 numerical rating scale. All combinations of discomfort and visual condition were presented twice in a fully randomised order. Results: Group mean discomfort scores (± 95% confidence interval) for each lens type and vision condition were as shown in the accompanying table. Differences between lens types (p = 0.0005) and visual conditions (p = 0.03) were significant (ANOVA with repeated measures) such that subjects reported greater discomfort under conditions of visual blur than they did with either full correction or occlusion. Conclusion: Reducing visual quality, but not eliminating vision entirely, increases perceived ocular discomfort. The severity of subjective ocular discomfort symptoms may be increased for conditions in which there is an associated visual compromise. Attempts to measure discomfort responses should be made with vision either optimised, or occluded. Group Mean Discomfort Response
Keywords: innervation: sensation • visual acuity • contact lens