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Nancy Coletta, Anne Moskowitz; Wavefront aberrations and mesopic visual performance following soft contact lens removal. Journal of Vision 2003;3(12):37. doi: 10.1167/3.12.37.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Soft contact lens (SCL) wear is associated with corneal swelling that tends to increase central more than peripheral corneal thickness. This differential swelling across the cornea could alter the eye's wavefront aberrations. We examined aberrations and mesopic contrast sensitivity within the first hour after SCL removal. Methods: Two groups of myopic subjects were tested: 11 habitual SCL wearers and 11 spectacle wearers. Mean age was 26.5 years and mean spherical equivalent was −5.47 D. The SCL group had been wearing lenses for at least 6 hours prior to testing. Whole-eye aberrations were measured with a Shack-Hartmann wavefront sensor (Wavefront Sciences COAS) and anterior corneal aberrations were determined from corneal topography. Contrast sensitivity functions (CSF) were measured at a luminance of 4 cd/m2 using a 2AFC method. All subjects were corrected with trial lenses during CSF testing; mean pupil diameter was 6.3 mm and did not differ between the groups. Results: For both groups, corneal aberrations were larger than whole-eye aberrations, indicating compensation of whole-eye aberrations by the internal optics. Both whole-eye and corneal aberrations were greater in the SCL wearers than in the spectacle wearers. SCL wear mainly increased fourth-order aberrations, particularly positive spherical aberration (SA). This increase in positive SA was more evident in the whole eye than in the cornea, implying that internal compensation of positive SA is reduced in SCL wear. The mean CSF was 0.16 log unit lower in the SCL group at 4 and 8 cpd. Conclusions: Compared to non-contact lens wearers, subjects who have worn SCLs have increased wavefront aberrations, and reduced mesopic contrast sensitivity at middle spatial frequencies. The eye's internal optics affect the aberrations in SCL wearers, probably due to changes in the posterior corneal surface shape.
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