Nearsightedness or myopia is a condition in which near objects are seen clearly, but distant objects are not clear. This occurs due to light rays focussing in front of the retina due to either a longer eye ball or increased corneal curvature.

Nearsightedness is a common vision condition affecting nearly 20 per cent of the Indian population. High myopia usually describes myopia of -6.00 or more. Roughly 30 per cent of myopes have high myopia.

Who can undergo EpiLasik treatment?
nEpilasik is a new form of LASIK, which is a better option for some patients who will probably not get very good results with LASIK. These include people who have thin corneas, which is not good for a LASIK flap. This procedure involves removing the superficial epithelium and giving laser treatment.

Epilasik is a much more painful surgery than LASIK in the first few post-operative days and involves slower recovery.

What is aspheric LASIK?
nAspheric LASIK, a breakthrough in Lasik, maintains the natural aspheric shape of the cornea minimising the induction of aberration and ultimately, providing the patient with better quality of vision — especially in dim light.

What is femtosecond laser?
*This procedure involves making the corneal flap with a femtosecond laser rather than a mechanical microkeratome with a metal blade.

What are the new options for treatment of high myopia?
*Phakic intraocular lenses, or phakic lenses, are lenses made of plastic or silicone that are implanted into the eye permanently to reduce a person's need for glasses or contact lenses. Phakic intraocular lenses are implanted in the eye without removing the natural lens. This is in contrast to intraocular lenses that are implanted into the eyes after the eye's cloudy natural lens (cataract) has been removed during cataract surgery.

What results can I expect from LASIK?
*LASIK is the acronym for laser in situ keratomileusis, sometimes referred to as laser assisted in situ keratomileusis. The name refers the use of a laser to reshape the cornea without invading the adjacent cell layers.

LASIK improves the uncorrected vision — one's vision without wearing corrective lenses — in most patients who undergo the procedure. Over 90 per cent of patients with low to moderate myopia will achieve 20/40 vision, which is considered the minimum allowed by most countries to drive without having to wear contacts or glasses.
The physical results are permanent. However, you should be aware that since the eyes can still change with time, some power can come back in 3-5 per cent of cases.  Depending on the cause, re-treatment may be a viable solution to vision changes later in life.

Does the LASIK procedure hurt?
*Patients are given a topical anaesthetic (eye drops) to numb the eye, so they experience no pain during the procedure. When the surgeon applies the vacuum ring, the patient experiences a sensation of pressure just before his or her vision fades for a few seconds. The microkeratome — the instrument the surgeon uses to create the flap — and the laser do not cause any pain or discomfort. For several hours after the procedure, many patients describe of a mild burning sensation though.

How safe is the LASIK procedure?
*According to several large studies, there is approximately a 2 per cent intra-operative and 3-5 per cent post-operative complication rate. Most of these complications do not result in loss of two or more lines of best corrected visual acuity or interfere with vision long term. The rate of severe complications should be substantially less than 1 per cent. It is important for patients to understand that LASIK is a surgery, and a small incidence of complications is to be expected.

You may be under treated or over treated.

*Failure to get the desired result is the commonest complication of LASIK surgery. It could be under or over correction of the refractive error. A larger degree of over or under correction may be corrected by re-touchup; lifting the flap (even months after the surgery) and applying additional laser ablation.

Some patients develop debilitating visual symptoms.

nSome patients develop glare, halos, and/or double vision that may affect nighttime vision. Even with good vision on the vision chart, some patients do not see as well in situations of low contrast, such as at night or in fog, after treatment as compared to before treatment. Usually these symptoms reduce by six months.

Some patients may develop severe dry eye syndrome.

*As a result of surgery, your eye may not be able to produce enough tears to keep the eye moist and comfortable.. This condition may last for a long time and intensive drop therapy and use of plugs or other procedures may be required.

Some develop rare complications
nSome rare complications are mechanical microkeratome failure, which needs postponement of surgery for few months.

Corneal ectasia (thinning of cornea) where cornea becomes unstable and thin. The refractive error increases and patients may need contact lens for visual correction. This condition can be prevented by detailed pre-operative evaluation.

Everyone who has refractive surgery will achieve perfect vision
*Untrue. Surgeons aim for results of 20/20 (6/6) or better so that you can perform most daily activities without your glasses.

LASIK can be done on all myopes
*Certain conditions and circumstances completely preclude individuals from being candidates for LASIK surgery. Non-candidates include individuals who:
Have diseases such as cataracts, Keratoconus, dry eye etc

Do not give informed consent. It is absolutely necessary that candidates adequately discuss the procedure and its benefits and risks with their surgeon, and provide the appropriate consent prior to undergoing the surgery.

Have unrealistic expectations.

The author is vice chairman and cornea refractive surgeon, Narayana Nethralaya and can be contacted at 66121300 (ext 305)