#132 LASIK and LASEK Surgery (English)

LASIK and LASEK Surgery

 LASIK (Laser In-Situ Keratomileusis) is a type of refractive surgery for the correction of myopia, hyperopia, and astigmatism. The LASIK surgery is performed by an ophthalmologist who uses a laser or microkeratome to reshape the eye’s cornea in order to improve visual acuity.

Myopia, Hyperopia, Astigmatism

 The eye surgeon uses either microkeratome or femtosecond laser to create a thin, circular “flap” in the cornea. Before the incision, topic anesthetic drops are required to prevent any discomfort during the procedure. Also, the ink marker marks the cornea before creating the flap to indicate the incision area. Eye movements are prevented by fixing the eye by applying a suction ring. After the opening of the flap, the surgeon folds back the hinged flap to access the underlying cornea (stroma) and removes some corneal tissue using an excimer laser. Excimer laser is a form of cool ultraviolet light beam. It is used to ablate microscopic amounts of tissue from the cornea to reshape it so the retina more accurately focuses light and improve vision. For myopic people, the cornea is flattened, but for hyperopic people, the cornea is steeper. In case of astigmatism, the laser smooths the irregular cornea into a more normal shape. After the reshaping the cornea, the flap is then put back in place, covering the area where the corneal tissue was removed. Then the cornea heals naturally.

Microkeratome

 LASEK (Laser Assisted Sub-Epithelial Keratomileusis) is a type of surgery changing the shape of the anterior central cornea using an excimer laser to ablate a small amount of tissue from the corneal stroma at the front of the eye, just under the corneal epithelium.

 The surgical procedure is similar to one another, yet he main difference is that LASIK surgery creates a thin flap including corneal stroma tissue in the cornea, whereas in LASEK the cornea’s entire epithelial layer is removed by trephine to expose the area. Like LASIK, LASEK uses the excimer laser then sculpts the stromal layer of the cornea to correct the vision.

Structure of the Cornea

 The healing and recovery take 2~7 days in LASIK. However, in LASEK, it takes about 4~7 days to recover, which is slightly longer than LASIK. LASIK is appropriate for people who have adequate thickness of corneal tissue. People with less corneal tissue proceed LASEK surgery. In LASEK surgery, more corneal tissue is preserved after the procedure.  

[Reference]

https://en.wikipedia.org/wiki/LASIK
https://en.wikipedia.org/wiki/Excimer_laser
http://www.allaboutvision.com/visionsurgery/lasik.htm
https://en.wikipedia.org/wiki/Photorefractive_keratectomy
http://www.allaboutvision.com/visionsurgery/prk.htm
http://www.the-lasik-directory.com/lasik_lasek_chart.html

LASIK surgery procedure

https://www.youtube.com/watch?v=UezYWOqPQ_Q

Comparison of LASIK and LASEK surgery

https://www.youtube.com/watch?v=dKANhIU7Sxk

KSJ