Accuracy of Manufacturers' Stated Center Thickness of Hydrogel Contact Lenses

The center thicknesses of 184 hydrogel lenses–Naturvue, Hydrocurve (thin hefilcon A), Soflens, Aquaflex, and AOsoft–were measured using the Radiuscope in combination with the hydrogel lens platform. The measured center thickness of each lens was compared with the manufacturer's stated center thickness for a lens of the same parameters. In all cases, the mean difference between the measured center thickness and stated center thickness exceeded 0.01 mm, which, based on previous study, was the expected variation in the technique. The moan difference between the measured center thickness and stated center thickness of the various manufacturers' lenses ranged from 0.012–0.030 mm.