Purpose: Ocular discomfort is the primary reason for discontinuation of contact lens wear. The purpose of the study was to quantify and compare the frequency of ocular symptoms experienced by spectacle wearers and wearers of soft and rigid daily contact lenses.
Methods: We analyzed the results of an ocular symptom survey of prospective volunteers for contact lens clinical trials during the period 1989 to 1995. Questions pertaining to lens-wear experience and ocular symptoms were answered by 883 untrained individuals without active ocular disease. The sample included 664 spectacle wearers, 171 soft contact lens (SCL) wearers, and 48 rigid gas-permeable (RGP) lens wearers. The frequencies of 10 ocular symptoms were compared for each group. Spearman's Rank Correlation was used to test for correlations between symptoms. The X2 test was used to determine differences between subject groups, adjusted for multiple comparisons.
Results: There were no significant differences in the frequency of ocular symptoms between the soft contact lens (SCL) and RGP wearers. The most common symptom was ocular tiredness (27%). None of the symptoms were highly correlated, indicating that they are somewhat different "sensations." Despite ocular discomfort being the primary reason for discontinuation of lens wear, contact lens wearers experienced the same type and severity of symptoms as spectacle wearers. Thus (in order of frequency of occurrence), tiredness, itchiness, watering, pain, aching, excessive blinking, and burning had similar rates of occurrence for all three groups. The two major distinguishing symptoms were dryness and redness, which were reported far more frequently and with greater severity in both contact lens groups (p < 0.001). Grittiness was also reported more with RGP wearers than with spectacle wearers (p < 0.001).
Conclusions: Contact lenses disturb the ocular environment, as evidenced by responses of increased ocular dryness, redness, and grittiness. Despite fundamental differences in SCL's and RGP contact lenses, both groups of contact lens wearers surveyed experienced a similar type and frequency of ocular symptoms.
(C) 1999 American Academy of Optometry