Bansal Shveta, Quah Say A, Turpin Tim, Batterbury Mark
Department of Ophthalmology, St James' University Hospital, Leeds, UK.
Clin Exp Ophthalmol. 2008 Mar;36(2):156-8. doi: 10.1111/j.1442-9071.2008.01700.x.
The ability to perform biometry accurately on a dilated pupil can greatly facilitate the efficiency of a cataract service as it can be done on the day of surgery. The purpose of this study was to assess the repeatability of axial length (AL) calculations in undilated pupils and measure the difference in predicted and actual refractive outcomes in dilated pupils compared with undilated pupils.
First, intraobserver repeatability was assessed by taking two consecutive recordings of AL using applanation A-scan ultrasonography in undilated pupils in 21 eyes. The mean AL for each eye was compared with a measurement made following pupil dilatation. Second, we audited the mean spherical equivalent refractive errors following routine cataract surgery in 38 patients with undilated pupils and 36 patients with dilated pupils.
The mean difference in intraobserver measurements was -0.05 mm (standard deviation [SD] 0.15) with pupils undilated. Following pupil dilatation, the mean dilated AL differed from the mean undilated AL reading by only 0.03 mm (P > 0.05). The mean differences between planned and actual refractive error were 0.71D (SD 0.54) and 0.55D (SD 0.41) in dilated and undilated patients, respectively. This was not statistically significant (P > 0.05). The range of differences between target and actual refraction was -1.45D to 2.70D for undilated patients and -1.88D to 1.18D in dilated patients.
Although there was a greater spread of postoperative refractive errors in the dilated group, there were no statistically or clinically significant differences in postoperative refractive errors between the two categories of patients. Our study shows that applanation biometry may be safely performed for the purpose of cataract surgery after pupil dilatation.
在散瞳状态下准确进行生物测量的能力可极大提高白内障手术服务的效率，因为这可以在手术当天完成。本研究的目的是评估在未散瞳瞳孔中眼轴长度（AL）计算的可重复性，并测量与未散瞳瞳孔相比，散瞳瞳孔中预测屈光结果与实际屈光结果的差异。
首先，通过在21只眼的未散瞳瞳孔中使用压平A超超声检查连续两次记录AL来评估观察者内重复性。将每只眼的平均AL与散瞳后进行的测量值进行比较。其次，我们审核了38例未散瞳瞳孔患者和36例散瞳瞳孔患者常规白内障手术后的平均等效球镜屈光不正。
未散瞳时观察者内测量的平均差异为-0.05mm（标准差[SD]0.15）。散瞳后，散瞳后的平均AL与未散瞳时的平均AL读数仅相差0.03mm（P>0.05）。散瞳和未散瞳患者计划屈光不正与实际屈光不正之间的平均差异分别为0.71D（SD 0.54）和0.55D（SD 0.41）。这在统计学上无显著差异（P>0.05）。未散瞳患者目标屈光与实际屈光之间的差异范围为-1.45D至2.70D，散瞳患者为-1.88D至1.18D。
虽然散瞳组术后屈光不正的离散度更大，但两类患者术后屈光不正的差异在统计学和临床上均无显著意义。我们的研究表明，为白内障手术目的，散瞳后进行压平生物测量可能是安全的。
