How Does Laser Work on Myopic Eyes?

In simple words, laser is used to reduce the thickness of the centre of cornea by the process of oxidation, which is called by the eye specialist as ‘ablation’ (see diagram).

The steps of the procedure in brief are as under:

Local eye drops are given four or six times. The person is fully conscious and needs no systemic or general anesthesia; in fact, the patient and the surgeon may be talking to each other. The procedure is painless.

The person lies on a table and the top of the table has a mounted microscope connected to a laser machine. The machine is automatically controlled by a computerized data machine. The machine has all the data of the person’s corneal thickness, error of refraction, I.e. power of the spectacle glasses to be corrected, laser depth and all the precise parameters in full to ablate the layers of the cornea.

Let us elaborate here the recent advancements in the techniques that have evolved.

Laser (PRK) is an old technique where the corneal surface is hit by laser directly and the laser is called exciter laser’ which is a unique laser beam different from others.

In the recent technique a thin corneal flap is cut by a keretome and lifted up baring the inner surface where the exciter laser beam is hit to make the centre of cornea thin to the required depth. The higher the power of myopia the greater is the corneal depth hit by the laser. This technique is termed as Lasik. It is now in vogue all over the world and in some centers of our country. It has many advantages, e.g. quick recovery, no aftereffects of glare and blurring, and full vision in few days.

There is another improved technique over the Lasik, called wave-front Lasik that hits all the points of the cornea mapped out by an aerometer. It is a marvel of modem laser technology of ophthalmic sciences. If the operation is successfully performed the person achieves above normal sight without glasses.

It suffices to state that all the procedures are fully automated by the laser surgeon who is trained and has the expertise from national and international centers. He should have performed about 500 laser procedures under the care of a master laser specialist.

The laser machine with its accessories, is expensive and costs around 3-4 cores. It is insured for maintenance by high-tech engineers of electronics and software at heavy costs. It is an outdoor procedure and does not need hospitalization. It takes ten minutes to perform the operation.

Lasik is more technically perfect than other forms of refractive surgery. It is safe and successful all over the world.

The post Lasik recovery period is about three-four days and the patient gets back to routine in seven days, the patient does not experience any pain.

Following are the prerequisite criteria for a person to be fit for Lasik?

Age 19 to 21 years is most essential for laser in myopic eyes. At this age the increase in the power of minus number stabilizes. When the height of a person stops increasing, i.e. at the age of 19-21 the myopia stops increasing.

Lasik is never performed and contraindicated in an increasing state of myopia.

Eye components must be normal, healthy and free from any diseases, e.g. glaucoma, corneal scars, retinal and vitreous diseases and cataract.

The ideal range for Lasik procedure on myopia is -3 to -15. However, the specialist decides the criteria. Lasik in plus numbered glasses hypermetropia and glasses with astigmatism compound can also be performed on +3 to + 10 in persons who wear high plus glasses. They are a minority group unlike myopias.