Corneal Zernike aberrations for different pupils: precision in the parameters and applications

Ocular wavefront aberration is usually expanded in Zernike modes. In previous papers formulas for coefficients of up to 7th order corresponding to a new pupil in terms of those computed for an original pupil are obtained and program SLG07 that evaluates them is developed. In the present paper, original corneal aberrations of various eyes computed in the corneal topographer SN CT1000 are considered. Six factors affecting the precision in the coefficients are analyzed: ocular fluctuations, uncertainty in the original coefficients, original pupil size, maximum order in the expansion, analytical calculation instead of tracing rays and precision in the SLG07 entrance data. The uncertainty in the original coefficients results to be a fundamental factor.