title: A comparison between the measured and the desirable quality of hydrogel extended wear contact lenses.
abstract: Eighty-two hydrogel extended wear contact lenses (EWCL) from four brands were tested for overall quality and variations in specified parameters. Two of the EWCL brands were approved by the United States Food and Drug Administration (FDA) for wear by the public, while two of the brands were uninvestigated. In addition, the packaging solution was examined for osmolarity and pH. All brands were delivered with solutions that had estimated means of pH and osmolarity departing from what may be considered ideal physiologically. The EWCLs all had a consistent power and an acceptable thickness reproducibility. One of the FDA approved brands, demonstrated diameter variations of a magnitude that may produce an unpredictability in the lens fit. Several lenses of one brand suffered from edge quality deficiencies. Although the FDA clinical trial is designed to control the clinical performance of contact lenses prior to the market entry, the results of the present investigation indicate that an authority independent of the manufacturer should regularly sample the lens quality. It is for this purpose imperative that standards for contact lenses are established.
mesh_terms: D003262:Contact Lenses, Extended-Wear / Q000592:standards*; D003263:Contact Lenses, Hydrophilic / Q000592:standards*; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D011786:Quality Control