Chang John S M
Department of Ophthalmology, Hong Kong Sanatorium & Hospital, 8/F, Li Shu Pui Block, Phase II, 2 Village Road, Happy Valley, Hong Kong.
Eye Vis (Lond). 2018 Mar 12;5:6. doi: 10.1186/s40662-018-0099-9. eCollection 2018.
Astigmatic keratotomy (AK) remains an accessible means to correct surgically induced or naturally occurring astigmatism. The advantages of femtosecond laser-assisted astigmatic keratotomy (FSAK) over conventional methods have been recognized recently.
This review evaluates the efficacy, complications, and different methods of FSAK for correction of astigmatism in native eyes and those that underwent previous penetrating keratoplasty (PKP).The penetrating and intrastromal FSAK (IFSAK) techniques can reduce post-keratoplasty astigmatism by 35.4% to 84.77% and 23.53% to 89.42%, respectively. In native eyes, the penetrating and IFSAK techniques reduce astigmatism by 26.8% to 58.62% and 36.3% to 58% respectively, implying that the magnitude of the astigmatic reduction is comparable between the two FSAK procedures. Nonetheless, IFSAK offers the additional advantages of almost no risk of infection, wound gape, and epithelial ingrowth. The use of nomograms, anterior-segment optical coherence tomography, and consideration of posterior cornea and corneal biomechanics are helpful to enhance the efficacy and safety of FSAK. The complications of FSAK in eyes that underwent PKP include overcorrection, visual loss, microperforations, infectious keratitis, allograft rejection, and endophthalmitis. The reported difficulties in native eyes include overcorrection, anterior gas breakthrough, and suction loss.
In eyes that underwent PKP, FSAK effectively reduces high regular or irregular astigmatism, with rare and manageable complications. Nevertheless, the drawbacks of the procedure include the potential loss of visual acuity and low predictability. For native eyes undergoing femtosecond laser-assisted cataract surgery, IFSAK is a good choice to correct low astigmatism (< 1.5 diopters). The refractive effect of astigmatism from the posterior cornea needs to be considered in the nomograms for native eyes undergoing refractive cataract surgery. To further improve the efficacy of FSAK, more large-scale randomized studies with longer follow-up are needed.
散光性角膜切开术（AK）仍然是一种矫正手术引起的或自然发生的散光的可行方法。飞秒激光辅助散光性角膜切开术（FSAK）相对于传统方法的优势最近已得到认可。
本综述评估了FSAK矫正天然眼和既往接受过穿透性角膜移植术（PKP）的眼睛散光的疗效、并发症及不同方法。穿透性和基质内FSAK（IFSAK）技术分别可将角膜移植术后散光降低35.4%至84.77%和23.53%至89.42%。在天然眼中，穿透性和IFSAK技术分别将散光降低26.8%至58.62%和36.3%至58%，这意味着两种FSAK手术的散光降低幅度相当。尽管如此，IFSAK还具有几乎无感染、伤口裂开和上皮内生风险等额外优势。使用列线图、眼前节光学相干断层扫描以及考虑后角膜和角膜生物力学有助于提高FSAK的疗效和安全性。FSAK在接受PKP的眼中的并发症包括过矫、视力丧失、微小穿孔、感染性角膜炎、同种异体移植排斥反应和眼内炎。在天然眼中报告的困难包括过矫、前房气体突破和吸力丧失。
在接受PKP的眼中，FSAK可有效降低高度规则或不规则散光，并发症罕见且易于处理。然而，该手术的缺点包括潜在的视力丧失和低可预测性。对于接受飞秒激光辅助白内障手术的天然眼，IFSAK是矫正低度散光（<1.5屈光度）的良好选择。在接受屈光性白内障手术的天然眼列线图中需要考虑后角膜散光的屈光效应。为进一步提高FSAK的疗效，需要更多大规模、随访时间更长的随机研究。
