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Q. Yu, J. Wu, H. Zhang, L. Zhang, S. Ye, S. Dong, C. Zhang, J. He; The Change of Corneal Shape After Discontinuing Use of RGP Contact Lens by Wavefront Analysis. Invest. Ophthalmol. Vis. Sci. 2009;50(13):1570.
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© ARVO (1962-2015); The Authors (2016-present)
For RGP contact lens wearers, corneal shape is usually changed with the lens on-eye. Purpose of this study is to examine how long it will take for the cornea to return to its original shape after stop using the RGP contact lens.
Corneal topography was taken for 48 eyes of 24 subjects before and after one month RGP contact lens wearing, and the examination was followed at instantly, one day, three days, 7 days and 14 days after stop contact lens wearing. Wavefront aberrations of the anterior corneal surface (up to 7th order Zernike aberrations) was derived from corneal heights exported from the corneal topography system for analyzing the change in corneal shape.
Before RGP contact lens wearing, mean base-line Zernike aberrations in the anterior cornea were significantly different from zero for about half of the 12 terms (2nd to 4th orders). Four terms of the mean Zernike aberrations were significantly different from the base-line values when the RGP contact lenses were just removed from the eyes, these were defocus (C4=0.65,P=0.03, OD; C4=0.67,P=0.002, OS), main axis astigmatism (C5=-0.45,P<0.001, OD; C5=-0.65,P<0.001, OS), coma (C8=-0.15,P=0.002,OD; C8=0.17,P=0.006,OS) and spherical aberration (C12=0.18,P=0.015,OD). Only main axis astigmatism (C5=-0.63,P=0.011,OD; C5=-0.83,P=0.017,OS) was found significant when the RGP contact lenses were removed 1 day. Small changes on defocus and spherical aberration were observed after 3 days but not significant. At both 7 days and 14 days after the RGP lenses were removed, no significant difference was observed for any of the Zernike aberrations.
The results suggest that the anterior corneal surface is changed with the use of RGP contact lenses for one month, and it returns to its original shape completely within about 3 days if the contact lens use is discontinued.
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