Comparative assessment of the comfort of two soft contact lenses

Background: Perception of lens comfort is a critical factor and predictor of whether or not an individual will be able to successfully achieve refractive correction with contact lenses. Recent advances in lens materials raise the question of which materials are the best to prescribe. It is important to have some basis on which to compare the various materials in regards to comfort in addition to standard lab bench tests such as Dk and hydration percentage. Methods: The purpose of this study was to compare Brand A, a silicone hydrogel lens, with Brand B, a conventional hydrogel lens, in regards to wearer comfort. Twenty-nine subjects were randomly assigned to wear either Brand A or Brand B for four weeks and then the other brand for four weeks. Twenty-six subjects successfully completed the study. Subjects returned for follow-up visits at two and four week intervals after the initial fitting of each brand. Comfort was rated by acquiring subjective reports regarding comfortable wearing time and by marking an analogue comfort scale. Subjects also kept a home journal for recording comfort levels. Results: Statistical analysis showed virtually no difference in the subjects\u27 responses between the left and right eyes. As such only the data for the right eye was fully analyzed. The order in which the lenses were assigned was determined to not have a significant effect in the results; consequently, data was analyzed by brand without concern for an order effect. A slight decrease in comfort was noted for both brands from the two week reporting time to the 4 week reporting time. Conclusion: The data showed no significant difference between the brands in either subject comfort response or subjective hours of comfortable wear. It can be inferred that both Brand A and Brand B performed equally well in the perceived wearer comfort. This suggests that current silicone hydrogel lenses are as effective at maintaining sufficient lens hydration as conventional hydrogel lenses thereby providing an equally effective level of comfort longevity