高度近视眼矫正透镜放大率与视力

The relationship between magnification and visual acuity in biphakic eyes

目的评价高度近视眼在配戴框架眼镜和植入人工晶状体(intraocularlenses,IOLs)两种不同矫正方式中,透镜屈光力放大作用对术后矫正视力提高的影响程度。方法高度近视眼患者26例44眼,近视范围为-9.875^-24.75D,行有晶状体眼IOLs植入术,植入Verisys前房型IOLs,比较手术前后最佳矫正视力变化状况。同时,根据Gullstrand模型眼理论计算植入眼内的负度数IOLs与相应戴框架镜片状况下视网膜像放大率的变化,评价透镜的屈光度放大率与视力提高之间的关系。结果所有患眼的术前最佳矫正视力为4.2~5.0,平均为4.742±0.2435,IOLs植入后1个月的最佳矫正视力是4.5~5.3,平均为4.911±0.1956,两者差异具有显著性(t=11.234,P=0.000),IOLs植入术后最佳矫正视力明显高于术前框架眼镜的最佳矫正视力。根据IOLs的透镜屈光力放大率理论计算结果,屈光不正在-10^-30D范围内,植入的IOLs比框架眼镜的透镜放大率提高15%~45%,其变化值与最佳视力提高量有正相关关系(r=0.504,P=0.000)。结论透镜的屈光力放大作用是高度近视的有晶状体眼IOLs植入术后的最佳矫正视力改善的重要原因,IOLs植入术后最佳矫正视力比框架眼镜矫正的最佳视力可提高1~2行。

Objective To compare spectacle magnification and visual acuity in highly myopic phakic eyes corrected by anterior chamber intraocular lenses （IOLs） and eyes corrected with spectacles. Methods A comparative stndy was conducted on the change in best corrected visual acuity before and after anterior chamber intraocular lerases were inserted in 44 eyes （26 patients） with high myopis from - 9. 875 to - 24.75 D. Spectacle magnification （SM） in the myopic pbakie eyes corrected with both IOLs and spectacle lenses was calculated. The actual results were compared to theoretical predicrices.Results The BCVA of pre-operstion and post-operation is 4.742 ± 0.2435 and 4.911 ± 0.1956 respectively. There was significant difference between the results （t = 11.234, P= 0.000）. The result of spectacle magnification shows that phakic intraocular lens can magnify retinal image 15 % - 45% than spectacle in range from -10～ - 30 D myopia. There was positive correlations between magnification change and post-operative BCVA improvement （r = 0. 504, P = 0.000）. Conclusion Spectacle magnification is an important reason for improving BCVA in extreme high myopis. The pbakic anterior chamber intraocular lens can improve BCVA by 1 or more lines.