誗AIM:To compare the calculation method with diagnostic method in determining the power of rigid gas permeable contact lens (RGP) , and to notice that diagnostic method is superior to calculation method. 誗 METHODS: Sixteen cases (31 eyes) with myopia or myopic astigmatism were fitted by diagnostic method, after wearing optometry combined with vertex conversion to determine the RGP diopter, then using the determined RGP base curves combined with steep add minus(SAM) , flat add plus(FAP) principle

more »

... and the vertex conversion to calculate the RGP refraction. 誗RESULTS: In 31 eyes determined by calculating the RGP refraction, except 2 eyes蒺 diopter were similar with diagnostic method, the other 29 eyes were all overcorrected, more than half (18 / 31) eyes were overcorrected 逸-0. 50D. 30 eyes have corrected VA逸1. 0 with RGP fitted with diagnostic method, while only 1 eye has corrected VA as 0. 8. 誗 CONCLUSION: Calculation method can cause over correction of myopia in determining RGP power. The RGP power determined by diagnostic method is lower than that determined by calculation method. 誗 KEYWORDS: RGP; calculation method; diagnostic method; myopia Citation:Zhu RH. Calculation method and diagnostic method in determining the RGP diopter difference. Guoji Yanke Zazhi(Int Eye Sci) 2012;12(9) :1790-1791 摘要 目的:比较计算法和试戴镜法在确定硬性透氧性角膜接触 镜(RGP) 屈光度时的差异,阐明用试戴镜法验配 RGP 的 优越性。 方法:用试戴镜法验配的 16 例 31 眼近视和近视散光患 者,在戴片验光结合顶点换算确定 RGP 屈光度后,再用已 经确定的 RGP 基弧结合 SAM(steep add minus,即陡加负) 和 FAP(flat add plus,即平加正) 原则与顶点换算,计算出 RGP 的屈光度。 结果:(1) 计算法确定 RGP 屈光度的 31 只镜片中,除 2 只 的度数与试戴镜法相同外,其余 29 只全部过矫,半数以上 (18 / 31) 过矫逸-0. 50D。 (2) 根据试戴镜法确定屈光度