Ianchulev Tsontcho, Salz James, Hoffer Kenneth, Albini Thomas, Hsu Hugo, Labree Laurie
Doheny Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of California at Los Angeles, Los Angeles, California 90027, USA.
J Cataract Refract Surg. 2005 Aug;31(8):1530-6. doi: 10.1016/j.jcrs.2005.01.035.
To correlate intraoperative aphakic autorefraction to conventional emmetropic intraocular lens (IOL) calculations and derive an empiric predictive model for IOL estimation based on optical refractive biometry without axial length and keratometry measurements.
Institutional Review Board of the University of Southern California, Los Angeles County General Hospital, Los Angeles, California, USA.
A pilot group of 22 eyes of 22 patients scheduled for cataract surgery were enrolled in a prospective trial. All patients had a standard preoperative workup with subsequent cataract extraction and IOL implantation according to conventional biometric measurements and IOL calculations. Intraoperative autorefractive retinoscopy was used to obtain aphakic autorefraction and to measure the aphakic spherical equivalent before lens implantation. A linear regression analysis was used to correlate the aphakic spherical equivalent to the final adjusted emmetropic IOL power to empirically derive a refractive formula for IOL calculation (optical refractive biometry method). A second validation series of 16 eyes was used in a head-to-head comparison between the optical refractive biometry and the conventional IOL formulas. A subset of 6 eyes from the validation series were post-refractive cases having subsequent cataract surgery.
Intraoperative retinoscopic autorefraction was successfully obtained in all 22 patients in the pilot group and all 16 patients in the validation group. The spherical equivalent of the aphakic autorefraction correlated linearly with the final adjusted emmetropic IOL power (P<.0001, with adjusted r(2)=.9985). The relationship was sustained over an axial length range of 21.43 to 25.25 mm and an IOL power range of 12.0 to 25.5 diopters (D). In a subsequent validation series of 10 standard and 6 post-laser in situ keratomileusis (LASIK) cataract cases, the optical refractive biometry method proved to be a better predictive model for IOL estimation than conventional formulas; 83% of the LASIK eyes and 100% of the normal eyes were within +/-1.0 D of the final IOL power when aphakic autorefraction was used, compared with 67% of LASIK eyes and 100% of the normal eyes, using the conventional methodology.
A new model for IOL power calculation was derived based on an optical refractive methodology that breaks away from the conventional art introduced by Fyodorov in the 1960s. A purely refractive algorithm is used to predict the power of the IOL at the time of surgery without the need for axial length and keratometry measurements. This method bypasses some limitations of conventional biometry and shows promise in the post-refractive cataract cases.
将术中无晶状体眼自动验光结果与传统正视眼人工晶状体（IOL）计算方法相关联，并基于不进行眼轴长度和角膜曲率测量的光学屈光生物测量法得出IOL估算的经验预测模型。
美国加利福尼亚州洛杉矶县综合医院南加州大学机构审查委员会。
将22例计划行白内障手术患者的22只眼纳入一项前瞻性试验。所有患者均进行了标准的术前检查，随后根据传统生物测量和IOL计算进行白内障摘除及IOL植入。术中使用自动验光视网膜检影法获得无晶状体眼自动验光结果，并在植入晶状体前测量无晶状体眼的球镜等效度。采用线性回归分析将无晶状体眼球镜等效度与最终调整后的正视眼IOL屈光度相关联，以经验性得出IOL计算的屈光公式（光学屈光生物测量法）。在光学屈光生物测量法与传统IOL公式的直接比较中，使用了16只眼的第二个验证系列。验证系列中的6只眼为屈光手术后行白内障手术的病例。
试验组的22例患者和验证组的16例患者均成功获得术中视网膜检影自动验光结果。无晶状体眼自动验光的球镜等效度与最终调整后的正视眼IOL屈光度呈线性相关（P<0.0001，调整后r²=0.9985）。该关系在眼轴长度范围为21.43至25.25mm和IOL屈光度范围为12.0至25.5屈光度（D）内持续存在。在随后的10例标准白内障病例和6例准分子激光原位角膜磨镶术（LASIK）后白内障病例的验证系列中，光学屈光生物测量法被证明是比传统公式更好的IOL估算预测模型；使用无晶状体眼自动验光时，83%的LASIK眼和100%的正常眼的IOL最终屈光度在±1.0D范围内，而使用传统方法时，LASIK眼为67%，正常眼为100%。
基于一种光学屈光方法得出了一种新的IOL屈光度计算模型，该方法突破了20世纪60年代费奥多罗夫引入的传统技术。使用一种纯屈光算法来预测手术时IOL的屈光度，无需进行眼轴长度和角膜曲率测量。该方法绕过了传统生物测量的一些局限性，在屈光手术后白内障病例中显示出前景。
