1. LASIK is an acronym for “Laser assisted in-situ keratomileusis i.e.  a laser procedure for removal of glasses. 

1. Before the invent of lasik , other procedures like Radial Keratotomy or R.K (which involved giving radial incisions in the cornea) and thereafter Photo-Refrative  Keratectomy or PRK (involved simply  laser removal of a slice of cornea) used to be in vogue, however presently lasik is the most frequently done procedure for glasses removal. 

1. In lasik, partial thickness flap of cornea (clear circular disc covering  black of the eye like the front glass of a watch) is first cut with micro-keratome (special motorized knife) followed by laser ablating (cutting) of the bared corneal surface. The greater the power of glasses, the more is the cutting done.  Flap is then reposited back which adheres well to the lasered surface. 

1. A special type of “cold” laser called excimer laser is used for lasik. This laser is mentioned as cold laser because it does not  burn or cut tissues. Instead it directly breaks the molecular bonds. 

1. In myopes (short sighted individuals i.e.  those wearing minus power), light rays get focused before the retina. Lasik laser modifies the central corneal curvature in such a way that it gets  accurately focused on the retina producing a sharp & clear image. 

1. Results of lasik for myopia (upto 5-6D power)  are highly accurate &  reliable (provided corneal thickness is adequate & the corneal curvature is proper, this special testing is always done prior to the laser surgery) While results for the plus powers & high pure cylindrical powers, results are not so consistent  and reliable. 

Selection criteria for lasik

 Patient should  be  at least 17-19 years of age with stable power of  glasses for at least last 1 year (minimal power  change may not disqualify the patient from lasik). 

1. No associated complicating eye disease  should be present. If there are  retinal  degenerative  changes  or retinal holes/ tears  these should  be treated first (myopes are prone to develop retinal degenerations  & holes).

1. Patient should have adequate corneal thickness in proportion to the glasses power that is required to be removed.

1. Patient has to stop contact lens wear for at least 2-3 days before lasik, if patient is a soft contact lens user and for 1-2 weeks if patient is using semi-soft contact lenses.

During laser treatment 

Patient has to lie flat on his back on a couch . Local anesthetic and antibiotic drops are put,  so that the laser treatment becomes absolutely painless (no injections are given). After the eyes  have been cleaned, don’t touch  your face or eyes or the sheet used to cover the face. Eyelids are held open and patient is asked to   fixate on the bigger red light  and not the small blinking green light without fail (other eye is kept covered to avoid distraction). During  treatment, patient may feel total blackout  of vision temporarily. Patient “must not” move his eyes or head or try to blink during actual laser treatment which takes only 20-60 seconds in normal cases. During laser, tic-tic sound will come and burning smell may be felt. You may ask verbally for any help or query. Both eyes can be treated at the same sitting and the patient is sent home after surgery without patching, but wearing dark goggles.

After care of lasik 

1. Vision stabilises fully in about 2-3 weeks although patient can start his work right from the next day itself; although slight fluctuation in vision, especially during evenings  is not uncommon .
2. Patient goes home after sometime wearing the dark goggles and has to start the eye drops from the next day and continue them  for a period of about 4 weeks.
3. Avoid putting water into the eyes for about 3 days (i.e. avoid head-bath).
4. Avoid splashing of water and forcible rubbing of  eyes for about 3 months  as flap attaches  fully by then.
5. Avoid using eye make up for initial 1 week
6. Any unusual  pain in the lasered eye must be reported to the doctor
7. There are no restrictions in diet, movements, reading, watching TV, etc.

Possible side effects and risks of lasik 

Although lasik surgery is reasonably safe, no surgical  procedure however small is absolutely safe and untoward and unforeseen complication may rarely occur . No guarantee can be given regarding absolute corrections as under or over corrections  may rarely occur.

Serious complications like infection causing loss of eye are very rare . Rarely haziness, scarring and induced cylindrical power may remain forever. For major under-corrections enhancement surgery (re-lasering) may sometimes be required. Those approaching 40 years of age may need plus power glasses for reading even after laser correction.