Department of Ophthalmology, Faculty of Medicine, Zagazig University, Zagazig, Sharkia, Egypt.
Graefes Arch Clin Exp Ophthalmol. 2010 Jul;248(7):1029-35. doi: 10.1007/s00417-009-1272-6. Epub 2010 Feb 6.
The techniques of limbal relaxing incision (LRI) and photoastigmatic keratectomy (PAK) are both effective methods for correcting pre-existing astigmatism with cataract extraction, but no previous study has directly compared them.
To compare the effects of limbal relaxing incision (LRI) and photoastigmatic keratectomy (PAK) on preoperative astigmatism and higher-order aberrations (HOAs) in eyes undergoing cataract surgery.
Kitasato University Hospital, Japan.
A retrospective study of eyes which had undergone phacoemulsification and intraocular lens implantation through an astigmatically neutral incision either accompanied by LRI (LRI group, 20 eyes) or followed after 3 months by PAK (PAK group, 27 eyes), to control pre-existing corneal astigmatism.
Among eyes that underwent LRI, manifest astigmatism (corrected to the corneal plane) averaged -1.72 +/- 0.95 D preoperatively and -0.98 +/- 0.58 D postoperatively. Corneal astigmatism averaged 2.03 +/- 0.49 D preoperatively and 1.34 +/- 0.60 D postoperatively. Among eyes that underwent PAK, manifest astigmatism averaged -2.02 +/- 0.64 D preoperatively and -0.70 +/- 0.58 D postoperatively. Corneal astigmatism averaged 2.30 +/- 0.81 D preoperatively and 1.05 +/- 0.36 D postoperatively. With regard to HOAs, in the LRI group, corneal HOAs averaged 0.172 +/- 0.051 microm (total aberrations for 4 mm pupil diameter) and 0.681 +/- 0.433 microm (total, 6 mm) preoperatively, but 0.172 +/- 0.053 microm (total, 4 mm) and 0.651 +/- 0.187 microm (total, 6 mm) postoperatively. In the PAK group, the corneal HOAs averaged 0.179 +/- 0.073 microm (total, 4 mm) and 0.679 +/- 0.314 microm (total, 6 mm) preoperatively, but 0.206 +/- 0.095 microm (total, 4 mm) and 0.816 +/- 0.380 microm (6 mm, total) postoperatively. The only statistically significant differences in the postoperative HOAs between LRI and PAK groups were in the S4 and S6 (spherical and spherical-like aberrations being bigger in the PAK group ).There were no vision-threatening complications in either group.
PAK is more effective than LRI in the control of pre-existing manifest astigmatism. LRI causes less accentuation of the spherical HOAs than PAK.
角膜缘松解切口（LRI）和光像差角膜切削术（PAK）都是矫正白内障摘除术后存在的散光的有效方法，但以前没有研究直接比较过这两种方法。
比较角膜缘松解切口（LRI）和光像差角膜切削术（PAK）对白内障手术患者术前散光和高阶像差（HOAs）的影响。
日本北里大学医院。
对通过散光中性切口行白内障超声乳化吸除和人工晶状体植入术的患者进行回顾性研究，其中一组行 LRI（LRI 组，20 眼），另一组术后 3 个月行 PAK（PAK 组，27 眼），以控制术前角膜散光。
行 LRI 的患者中，术前角膜散光平均为 -1.72 ± 0.95 D，术后为 -0.98 ± 0.58 D。术前角膜散光平均为 2.03 ± 0.49 D，术后为 1.34 ± 0.60 D。行 PAK 的患者中，术前平均散光为 -2.02 ± 0.64 D，术后为 -0.70 ± 0.58 D。术前角膜散光平均为 2.30 ± 0.81 D，术后为 1.05 ± 0.36 D。在 HOAs 方面，LRI 组术前角膜 HOAs 平均为 0.172 ± 0.051 µm（4mm 瞳孔直径总像差）和 0.681 ± 0.433 µm（总像差，6mm），但术后为 0.172 ± 0.053 µm（总像差，4mm）和 0.651 ± 0.187 µm（总像差，6mm）。PAK 组术前角膜 HOAs 平均为 0.179 ± 0.073 µm（总像差，4mm）和 0.679 ± 0.314 µm（总像差，6mm），但术后为 0.206 ± 0.095 µm（总像差，4mm）和 0.816 ± 0.380 µm（6mm，总像差）。LRI 和 PAK 组术后 HOAs 唯一具有统计学意义的差异是 S4 和 S6（球差和类球差在 PAK 组更大）。两组均无视力威胁性并发症。
PAK 在控制术前存在的显性散光方面比 LRI 更有效。LRI 引起的球差加重比 PAK 小。
