SRK式の信頼度について 術前屈折値の影響

Feasibility of Sanders-Retzlaff-Kraff formula for intraocular lens power setting. Influence of preoperative refractive value

　Sanders-Retzlaff-Kraff （SRK）式より求めた眼内レンズ度数と，術前に所持していた遠用眼鏡度数を術前屈折力と仮定することにより算出される眼内レンズ度数とを比較検討した．対象は術前に遠用眼鏡を使用しており，後房レンズ移植術を施行された98眼であった．その結果，術前の屈折値から算出された眼内レンズ度数とSRK式による値との間に差が認められる症例においても，SRK式は信頼できるものであった．すなわち，術前屈折値は水晶体による屈折変化の影響を受けていると考えられた．水晶体性遠視は前極白内障，皮質白内障で多く認められ，水晶体性近視は核白内障が主であった．

We evaluated the clinical value of Sanders-Retz-laff-Kraff (SRK) regression formula for calcula-tion of intraocular lens (IOL). The findings were compared with the refraction method based on the power of eyeglasses for the distance worn by the patient. A total of 98 eyes who underwent posterior chamber IOL implantation served as material ofthis study. The postoperative error was defined as the difference of predicted value of postoperative refraction and the actual one.

Our findings have shown the SRK formula to be reliable in all the cases. The preoperative refrac-tion seemed to be largely dependent on the re-fractive anomaly due to cataract. It appeared that a cortical cataract would induce lens-related hyper-opia and that a nuclear cataract would more likely develop lens-induced myopia.

Rinsho Ganka (Jpn J Clin Ophthalmol) 42(4) : 391-393, 1988