Long-term effects of extended wear lenses: changes in refraction, corneal curvature, and visual acuity

Extended wear lenses (Scanlens 75) +4.25 to -10.00 D were worn monocularly by 19 patients for an average of 5.4 years. The other eye of each patient was either emmetropic or amblyopic and no lens was worn. Both eyes were tested after lens removal and again 2 days and 7 days later. No significant differences in refraction, keratometry, or visual acuity were found between the experimental and control eyes. The amount of changes in both groups was not clinically significant: refractive changes averaged less than 0.37 D, keratometric changes averaged an equivalent 0.25 D, astigmatism increases were less than 0.25 D, and visual acuity was fully correctible to previous best visual acuity with spectacles in all cases.