自动检测角膜塑形镜偏位量的算法研究.

Objective To develop an automatic and objective quantification algorithm based on corneal topography to evaluate the orthokeratology (Ortho-K) lens fitting. Methods K-means algorithm was used to analyze the defocus ring of corneal topography and fit the most suitable ellipse on the defocusing region of corneal topography combining with weighted least squares method. The decentration distance was defined as the distance between the pupil center and the center of ellipse. Corneal topography images from 200 eyes (100 patients) were used to evaluate the accuracy and repeatability of the algorithm. Results The decentration distance was calculated using this automatic algorithm. One hundred and fourteen eyes (57%) had mild decentration, 75 eyes (37.5%) had moderate decentration and 11 eyes (5.5%) had severe decentration after wearing Ortho-K lenses. Compared with manual evaluation, the automatic algorithm showed higher accuracy and better repeatability. Conclusions Using K-means combining with weighted least squares algorithm, an objective and accurate algorithm was developed to evaluate Ortho-K fitting and could be used as an useful quantitative analysis tool for future clinical practice and research. [ABSTRACT FROM AUTHOR]