LASIK - Laser Assisted In Situ Keratomileusis

LASIK (Laser Assisted In Situ Keratomileusis) :

LASIK is a type of eye surgery done to correct refractive errors of the eye.

Refracrive error is based on two factors:

1.     Anterior-Posterior length of the eyeball (normally 23 mm)

·        Increased A-P length of the eyeball = myopia

·        Decreased A-P length of the eyeball = hypermetropia

2.     Corneal curvature:

a.      Steep corneal curvature > More bending / refraction > Image will form in front of retina > Myopia (refractory power is more)

b.     Flat cornea > Decreased bending > Image will form behind retina > Hypermetropia (refractory power is less)

c.      If corneal curvature is unequal > 2 images will be formed > Astigmatism

Principles of LASIK:

Reshaping of cornea (alter shape of cornea):

·        In myopia > make cornea flat

·        In hyper metropia > make cornea more steep

How much correction is possible?

·        Myopia > up to 16 D

·        Hypermetropia > up to 7 D

·        Astigmatism > up to 7 D

Procedure of LASIK:

Procedure of LASIK

1.     Make a thin corneal flap with automated microkeratome, attached at one end

2.     Treat bed with Excimer laser. Ablate Bowmen’s layer and stroma with laser > precisely cur tissue without disturbing surrounding structure.

3.     Reposition of flap

For 10µm ablation = correction of 1D myopia.

eg if you need 5 D correction = 50 µm tissue has to be ablated.

Note: Before LASIK, asses corneal thickness by pachymetry.

·        Normally centre = 0.56 mm

·        Periphery = 1.00 mm

Complication of LASIK:

1.     Wrinkling

2.     Decentration

3.     Cellular proliferation in between interface = becomes hazy

4.     Overcorrection or under-correction

5.     Ectesia (procedure not done in center, but to one side)

If you enjoyed this article and found it useful then please subscribe to my feeds via RSS or E-mail, and kindly take 5 minutes to share this article with everyone by clicking the "share this"button below. Thank you!

:

That's all for today!
If you liked this article and found it helpful then please share it with your friends and family and please consider becoming our Patron or buying us a coffee through PayPal. Your support enables us to continue blogging and help people. Also make sure your subscribe to our Newsletter so that you don't miss out on our future posts! Thanks!

Subscribe to Our Blog

Become Our Patron

Buy Us a Coffee