Limbal relaxing incisions
can correct a significant amount of pre-existing astigmatism.
Corneal refractive surgery includes laser eye surgery (LES) involving corneal ablation by excimer laser; corneal addition procedures such as intracorneal ring segments and epikeratophakia; corneal relaxation procedures such as radial keratotomy (RK), arcuate keratotomy (AK) limbal relaxing incisions
; and thermokeratoplasty.
Several methods have been employed for this purpose including changing the size and site of the incision,  using corneal or limbal relaxing incisions
,  applying opposite clear corneal incision on the steep axis,  implantation of toric Intraocular lens,  and laser keratomileusis.
Improves the accuracy Depth of incisions can be programmed, of limbal and corneal replacing a manual knife that has poor relaxing incisions
predictability and greater risk of perforation.
 Allen and Johnston believe that 1) optimal closure of a scalp flap requires two layers, 2) that flaps must not be closed under tension, so as to avoid ischemia at the suture line, and 3) that the closure of the galea aponeurotica should be separated from a second suture line through dermis  They suggest that minimizing scalp flap necrosis depends on 1) careful handling of the flap intraoperatively (excess manipulation or prolonged angulation after reflection can cause ischemia), 2) not using Raney clips (to avoid skin-edge ischemia), 3) assuring a good vascular supply by closing the wound with minimal tension (with the use of relaxing incisions
and flap undercutting if necessary), and 4) avoiding tight dressings postoperatively.
Possibilities are adjustment at the site of the surgical incision to produce corneal flattening (by operating on the steep axis), limbal relaxing incisions
(on the steep axis) or toric IOLs.