角膜B/F比值对年龄相关性白内障术后屈光误差的影响

The effect of corneal B/F ratio on postoperative refractive error after age-related cataract surgery

目的:分析角膜后前表面曲率半径比值(B/F比值)与年龄相关性白内障患者术后屈光误差的关系,探讨B/F比值对人工晶状体(intraocular lens,IOL)屈光力计算准确性的影响。方法:选取2019年3—11月在天津医科大学眼科医院白内障中心就诊,并拟行单眼白内障手术的年龄相关性白内障患者共197例(197眼),术前应用Pentacam眼前节分析仪测量患者眼前节生物参数,并以B/F比值下限25%、上限25%为界将患者分为下25%组、25%~75%组、上25%组。术后3个月应用全自动电脑验光仪评估患者术后屈光状态,并计算患者术后屈光误差(postoperative refractive error,PE),比较三组平均屈光误差(mean refractive error,ME)、平均绝对误差(mean absolute error,MAE)、中位数绝对误差(median absolute error,MedAE)以及屈光误差在±0.25、±0.50、±0.75、±1.00、>±1.00 D范围内百分比差异。结果:B/F比值与年龄相关性白内障患者术后屈光误差呈中度相关(r=−0.445,P<0.001)。随着B/F比值增大,患者术后屈光状态由远视向近视漂移,术后3个月MAE、MedAE分别为0.55 D、0.46 D。屈光误差在±0.25、±0.50、±0.75、±1.00、>±1.00 D范围的百分比分别为29.4%、52.8%、71.6%、87.6%、12.7%。根据正常年龄相关性白内障人群B/F比值优化得到的矫正角膜折射指数计算角膜曲率后,MAE、MedAE分别为0.51、0.43 D,均低于矫正前(P<0.05)。结论:B/F比值对年龄相关性白内障患者术后屈光状态有影响。随着B/F比值的增加,白内障患者术后屈光状态由远视逐渐向近视漂移,且B/F比值越偏离正常平均值,患者的屈光误差绝对值越大。

Objective:To analyze the relationship between corneal B/F ratio and postoperative refractive error in age-related cataract patients,and to explore the impact of B/F ratio on the accuracy of intraocular lens power calculation.Methods:A total of 197 age-related cataract patients(197 eyes)who were treated in the cataract center of our hospital from March 2019 to November 2019 expecting to have monocular cataract surgery were selected.The biological parameters of the anterior segment were measured by Pentacam anterior segment analyzer before surgery,and the patients were divided into three groups(25%below the B/F ratio,25%~75%,and 25%below the B/F ratio)with the lower limit and the upper limit of 25%.Three months after surgery,the postoperative refractive state of patients was evaluated by automatic computerized refractometer,and the postoperative refractive error(PE)was calculated,and the percentage differences of mean refractive error(ME),mean absolute error(MAE),median absolute error(MedAE)and refractive error in the range of±0.25,±0.50,±0.75,±1.00 and<±1.00D were evaluated.Results:The B/F ratio was moderately correlated with postoperative refractive error in age-related cataract patients(r=−0.445,P<0.001).With the increase of B/F ratio,the refractive state of patients shifted from hyperopia to myopia after surgery,and the MAE and MedAE were 0.55 D and 0.46 D respectively in 3 months after surgery.The percentages of refractive error in the range of±0.25,±0.50,±0.75,±1.00 and<±1.00 D were 29.4%,52.8%,71.6%,87.6%and 12.7%,respectively.After adjusting the corneal curvature according to the B/F ratio of the population based on our previous study,MAE and MedAE were 0.51 D and 0.43 D,respectively,which were lower than those before correction(P<0.05).Conclusions:There is a correlation between B/F ratio and postoperative refractive error in age-related cataract patients.As the B/F ratio increased,the refractive state of the patient gradually drifted from farsightedness to myopia after cataract surgery,and the more the B/F ratio deviated from the normal average,the greater the absolute value of the patient's refractive error.