PURPOSE: To assess the effect of different disposable soft contact lenses upon corneal thickness, and upon anterior and posterior corneal curvatures using a dual-Scheimpflug imaging based device. METHODS: Twenty-eight young, healthy subjects wore four different types of daily disposable soft contact lenses on four different days: Dailies Total1, Proclear 1 Day, Clariti 1-Day and 1-Day Acuvue Moist. The lenses had different material and water content. Pachymetry maps and keratometry values were obtained using the Galilei G4 twice a day: one before putting the lens on and one after an eight-hour period of contact-lens wear. Measurements were also recorded without any contact lenses being worn during a day. RESULTS: Clariti 1-Day lens caused the greatest thickening in the central (8.9±2.8 μm; p<0.01) and in the peripheral cornea (10.1±4.6 μm; p<0.01), whereas Dailies Total1 was the lens that had the most similar behaviour to the non-contact lens scenario. All the lenses caused a slight flattening in the anterior corneal curvature, except Clariti 1-Day, which induced a very slight steepening. The four lenses caused a steepening of different magnitude in the posterior corneal curvature. CONCLUSIONS: The magnitude of the changes introduced by the use of soft contact lenses over the eight-hour wearing period was rather small. Thus it is probable it will not influence the vision nor the comfort of the subject. Also, variations on corneal parameters seem to depend on the type of contact lens used.
PURPOSE: To assess the effect of different disposable soft contact lenses upon corneal thickness, and upon anterior and posterior corneal curvatures using a dual-Scheimpflug imaging based device. METHODS: Twenty-eight young, healthy subjects wore four different types of daily disposable soft contact lenses on four different days: Dailies Total1, Proclear 1 Day, Clariti 1-Day and 1-Day Acuvue Moist. The lenses had different material and water content. Pachymetry maps and keratometry values were obtained using the Galilei G4 twice a day: one before putting the lens on and one after an eight-hour period of contact-lens wear. Measurements were also recorded without any contact lenses being worn during a day. RESULTS: Clariti 1-Day lens caused the greatest thickening in the central (8.9±2.8 μm; p<0.01) and in the peripheral cornea (10.1±4.6 μm; p<0.01), whereas Dailies Total1 was the lens that had the most similar behaviour to the non-contact lens scenario. All the lenses caused a slight flattening in the anterior corneal curvature, except Clariti 1-Day, which induced a very slight steepening. The four lenses caused a steepening of different magnitude in the posterior corneal curvature. CONCLUSIONS: The magnitude of the changes introduced by the use of soft contact lenses over the eight-hour wearing period was rather small. Thus it is probable it will not influence the vision nor the comfort of the subject. Also, variations on corneal parameters seem to depend on the type of contact lens used.