Aflalo G
J Fr Ophtalmol. 1987;10(4):283-93.
After having recalled the principles of lens power calculation, we analyse in detail the parameters of the (Formula: see text). Corneal power K read on keratometers has to be modified, for it is about one diopter too strong. Evaluation of the anterior chamber depth C is analysed and corrected of 0.08 mm for the 1st C and of 0.06 mm for the 2nd C. Ultrasonic axial length L should be increased by the retinal thickness; the error induced by neglecting this correction is concealed by the overestimation of K in usual formulas. The equivalent power of the lens De is slightly underestimated relative to back surface power supplied by the manufacturer. The various formulas available in the Literature are commented and compared. A new formula is proposed, which is more particularly adapted to contact ultrasound probes, such as Digiecho II, which seem to under-evaluate L and C values.
在回顾了晶状体屈光力计算的原理之后，我们详细分析了（公式：见正文）的参数。角膜曲率计测得的角膜屈光力K必须进行修正，因为它大约强了1屈光度。对前房深度C进行了分析，并对第一个C修正了0.08mm，对第二个C修正了0.06mm。超声眼轴长度L应增加视网膜厚度；通常公式中因忽略此修正而产生的误差被K的高估所掩盖。晶状体的等效屈光力De相对于制造商提供的后表面屈光力略有低估。对文献中可用的各种公式进行了评论和比较。提出了一个新公式，该公式更特别适用于接触式超声探头，如Digiecho II，这种探头似乎低估了L和C值。
