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The Silicone Hydrogels website is partially supported through an educational grant from CIBA VISION

November 2004


Comfort and Vision with Inverted Soft Contact Lenses

N.Tahhan 1, L.Rodriguez 1, A.Demir 1, T.John 1, E.Papas 1, B.Holden 1, P.Caroline 2.
1 Vision CRC, UNSW, Sydney, Australia; 2 College of Optometry, Pacific University, Forest Grove, OR.


Purpose: The aim of this trial is to compare the vision and subjective comfort of three commercially available brands of soft contact lenses when inverted to when worn the correct way.

Methods: Ten subjects participated in multiple, 20 minute, contralateral, double masked randomised studies. In each trial, subjects wore an inverted lens in one eye and the same lens type, correctly inserted in the contralateral eye. Twelve lenses were tested and these include; Focus Night & Day (BC 8.4 and BC 8.6), Purevision and Acuvue 2. All lens types were tested in powers of +3 and -3. Subjective ratings of vision and comfort (scale 1-100) were recorded at baseline and after 20 minutes of lens wear. Results were analysed using Student's paired t-tests.

Results: At baseline, there was no significant difference between subject's right and left eyes for subjective ratings and visual acuities. After 20 minutes of wear, significantly worse vision and comfort ratings between lenses inverted and those inserted the correct way was found for the Acuvue lenses (all p<0.01). There were also significantly worse comfort ratings for the Purevision lenses (p<0.02) but vision was not significantly different. Comfort and vision was not significantly worse for any of the Focus Night & Day (BC 8.4) lenses and -3 (BC 8.6) lenses. Comfort was worse for the +3 BC 8.6) lenses (p=0.02) but not vision.

Conclusions: Practitioners generally advise their patients that if lenses are incorrectly inserted, they are likely to become aware of reduced comfort or vision. From our results, this holds true for Acuvue 2 lenses, but not for the silicone hydrogel lenses tested.
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