Department of Clinical Physiopathology, Ophthalmology Institute, University of Turin, Turin, Italy.
Am J Ophthalmol. 2013 Aug;156(2):254-259.e1. doi: 10.1016/j.ajo.2013.04.004.
To assess refractive error after cataract surgery combined with Descemet stripping automated endothelial keratoplasty using adjusted keratometric (K) readings to calculate intraocular lens (IOL) power.
Prospective, interventional case series.
One eye of 39 consecutive patients with Fuchs endothelial dystrophy and cataract were included. To calculate IOL power before surgery, the Javal steep and flat K readings (Haag-Streeit) were adjusted by reducing their value by -1.19 diopters (D); the axial length was measured by immersion biometry, and the standard A-constant was used. Surgery included phacoemulsification, IOL (Acrysof SN60AT; Alcon) implantation within the capsular bag, and Descemet stripping automated endothelial keratoplasty using posterior lamella prepared with a 300-μm head microkeratome (Moria). The absolute prediction error (absolute difference between predicted and achieved refraction) was assessed 6 months after surgery.
The mean power of the implanted IOL was 23.22 ± 2.90 D. The mean predicted and achieved refractions were -0.27 ± 0.26 D and -0.23 ± 0.73 D, respectively. The mean absolute prediction error was 0.59 ± 0.42 D (range, 0.05 to -1.52 D). The postoperative spherical equivalent fell within ±0.50 D, ±1.00 D, and ±2.00 D of the predicted refraction in 55.5%, 83.3%, and 100% of cases, respectively. Had the IOL power been calculated without adjusting the K readings, the mean absolute prediction error would have been significantly higher (0.86 ± 0.62 D; P = .04).
In this study, in which posterior lamellae were prepared using a 300-μm head microkeratome, adjusting preoperative K readings by -1.19 D led to accurate IOL power calculation and highly predictable refractive error after cataract surgery combined with Descemet stripping automated endothelial keratoplasty.
评估白内障手术后联合 Descemet 撕囊自动化角膜内皮移植术的屈光误差，使用校正角膜曲率（K）读数来计算人工晶状体（IOL）的屈光力。
前瞻性、干预性病例系列研究。
纳入 39 例连续的 Fuchs 内皮营养不良合并白内障患者的单眼。为了在术前计算 IOL 屈光力，通过将 Javal 陡峭和扁平 K 读数（Haag-Streit）值降低 1.19 屈光度（D）来调整读数；通过浸液生物测量法测量眼轴长度，并使用标准 A 常数。手术包括超声乳化白内障吸出术、IOL（Acrysof SN60AT；Alcon）在囊袋内植入和使用 300-μm 头部微型角膜刀（Moria）制备的后板层进行的 Descemet 撕囊自动化角膜内皮移植术。术后 6 个月评估绝对预测误差（预测值与实际屈光度的差值）。
植入的 IOL 平均屈光力为 23.22 ± 2.90 D。平均预测和实际屈光度分别为-0.27 ± 0.26 D 和-0.23 ± 0.73 D。平均绝对预测误差为 0.59 ± 0.42 D（范围为 0.05 至-1.52 D）。术后等效球镜在 55.5%、83.3%和 100%的病例中分别在预测屈光度的±0.50 D、±1.00 D 和±2.00 D范围内。如果不调整 K 读数来计算 IOL 屈光力，平均绝对预测误差将显著更高（0.86 ± 0.62 D；P =.04）。
在这项研究中，在后板层中使用 300-μm 头部微型角膜刀制备时，通过将术前 K 读数降低 1.19 D 可以实现白内障手术后联合 Descemet 撕囊自动化角膜内皮移植术的准确 IOL 屈光力计算和高度可预测的屈光误差。
