Lasik FAQ

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Learn about refractive errors and laser vision correction.


What are the causes of focusing problems?

Focusing problems of the eye, which require correction by glasses or contact lenses, are called refractive errors. These are:

  • Myopia, also called shortsightedness or nearsightedness
  • Hypermetropia (Hyperopia) also called or longsightedness or farsightedness
  • Astigmatism - those using cylindrical correction in their glasses


Nearsightedness, or myopia

It is the most common focusing problem, affecting a significant proportion of the Indian population. Nearsighted people can see various ranges of near objects clearly but not distant objects. Nearsightedness usually results from an eyeball that is too long. Because of this extra length, light from distant objects converges to a focal point before it reaches the retina at the back of the eye. Beyond the focal point, the light then begins to diverge. Since the retina only captures the quality of the image that reaches it, the brain receives a blurred image of what the eye is trying to see.
Nearsighted people need to wear minus-powered spectacles or contact lenses to see clearly.


Farsightedness, or hyperopia

This is a focusing problem caused by an eyeball that is shorter than normal. Due to the reduced length, the lens fails to bring light rays to a focal point by the time they reach the retina. The effects of farsightedness vary with age because of the diminishing flexibility of the lens. Young people may not notice any effects. But as the eyes begin to age, near objects become increasingly difficult to see. Later in life nearly all focal ranges may be unclear. Farsighted people need to use plus powered spectacles to see clearly.



Astigmatism is the result of the general inability of the eye to clearly focus images from any distance. It results from uneven curvatures of the cornea. Instead of being spherical, it is more similar to the side of an egg. This focusing problem usually occurs in combination with nearsightedness, or farsightedness. People with astigmatism need to use cylindrical correction in their glasses.


What are the life-style benefits of laser vision correction?

LASIK eye surgery offers multiple benefits to most people with refractive errors:

  • Clear vision without the hassles and inconvenience of corrective lenses - no more fears about being incapacitated in an emergency if lenses are lost or glasses are broken
  • Expanded career opportunities (police officers, firefighters, pilots, air hostesses and professional athletes).
  • Better vision for recreational sports, especially water, winter and contact sports
  • Wider scope of peripheral vision than what glasses provide
  • May be safer for eye health than wearing contact lenses for an extended period of time.
  • New visual freedom for all aspects of life


Do you qualify for Laser Vision Correction?

To qualify for laser vision correction, you should

  • Be at least 18 years of age
  • Have had stable vision for the past one year (slight prescription changes may not disqualify you.)
  • Have corneas of adequate thickness as measured by Corneal Pachymetry and normal shape (determined by Corneal Topography).
  • Be free from systemic illnesses, Collagen vascular disorders such as Rheumatoid Arthritis, Sjögrens Syndrome, Systemic Lupus Erythematosus, etc.
    Not be pregnant or nursing
  • Be off contact lenses for 1-3 weeks prior to the surgery (this varies with the type of contact lens - soft or semi-soft).
  • Your expectations from LASIK should be realistic. Patients with un-realistic expectations generally have low levels of satisfaction. Detailed patient counseling is important in this regard


How does laser vision correction work?

Laser vision correction works by using a high precision laser beam to reshape the front surface of the cornea and allow light rays to focus precisely on the retina. This high precision laser known as Excimer Laser involves the use of 193 nm UV light, which is a unique type of "cold" laser that does not burn or cut tissue. Instead, it gently breaks the molecular bonds between the cells so that controlled amounts of tissue can be literally vaporized away, one microscopic layer at a time. Central tissue is removed to reduce the corneal curvature and correct nearsightedness. Peripheral tissue is removed to increase the corneal curvature and correct farsightedness. Astigmatism can be corrected by removing selected tissue to even out the curvature of the cornea.


What is LASIK?

For people wishing to have less dependence on glasses or contact lenses, an excimer laser procedure called Laser Assisted in situ Keratomileusis (LASIK) is currently the best way to achieve clear, natural vision. This procedure had its origins back in the 1960s, and has evolved over the years into a safe and effective operation. This procedure was FDA recognized in September 1998.


In performing LASIK, the surgeon first uses a special oscillating blade to make a partial cut through one fourth to one third of the front surface of the cornea, creating a flap of clear tissue on the central part of the eye.

he patient is then positioned under the excimer laser, which is programmed to vaporize some of the internal corneal tissue under the flap. After the laser has removed the selected tissue, the flap is closed over the eye. The cornea has extraordinary natural bonding qualities that allow effective healing without the use of stitches.

In the latest technique of i-LASIK or Blade-free LASIK, this flap is created not by an oscillating blade, but by an advanced technology called the Intralase Method utilizing a special laser (femtosecondlaser).


What is Customized LASIK (Advanced CustomVue Treatment)?

Customized LASIK is an advanced form of laser vision correction, which further enhances the precision of excimer laser surgery. This is based on the fact that the human eye suffers not only from sphero-cylindrical errors, which can be corrected with glasses or contacted lenses, but also from numerous, minute optical imperfections or aberrations, other than sphero-cylindrical refractive errors, which are not correctable with glasses or contact lenses.


The LASIK Procedure

Each patient goes through a comprehensive series of eye tests and examinations (including Corneal Topography, Pachymetry and Wavefront analysis) before consulting with the surgeon to discuss and plan the specifics of personal vision correction. To ensure a painless experience the eye is anaesthetized with drops (No injections are necessary). For the surgery, the patient lies under the laser machine and concentrates on a flashing light for a few seconds. The patients are in the surgery suite for about 15-20 minutes and can walk away after the surgery. No hospitalization is required. In LASIK, both the eyes are generally operated at the same time; no patch is applied post-operatively. However, if you so desire, you may undergo the procedure one eye at a time.


What happens after LASIK?

The vision may be blurry for the first few hours after surgery but it gradually improves. Few patients may have a mild discomfort in the first two hours after the procedure. However, this is easily relieved by pain-killing medication. Patients are encouraged to rest for a day after the surgery. The precautions, which need to be taken post-operatively, are to avoid rubbing and squeezing the eyes. Avoid splashing water to the face or directly into the eyes. Instillation of eye drops would start immediately after the surgery and will continue for approximately two weeks. Most patients have functional vision and can resume normal activities and work within a few days. In LASIK, good vision is attained in 2-3 days. You will have follow up examinations on the day after the surgery, after the first week, one month, 2 months, 3 months and 6 months later


Risks and side effects of LASIK

As with any surgical procedure, LASIK surgery has some possible risks and side effects that must be taken into account. A specific end result cannot be guaranteed, although it can be closely predicted based on data from thousands of previous cases. Side effects are usually minimal following LASIK surgery. During the first few days after surgery, most people can expect to experience at least some of these effects:

  • Increased sensitivity to light or glare.
  • Gritty and burning sensation in the eyes
  • Slightly drier eyes
  • Decreased visual clarity in dim light

In most cases, these effects decrease and eventually disappear as the eye heals. Occasionally, somemay persist.

Serious complications are fortunately very rare. Some of these include infection, wrinkles in the flap, epithelial in growth and increased or decreased response to correction. These complications are treatable with medication or further surgery.


Epi-LASIK Eye Surgery

Epi-LASIK is a relatively new procedure that is technically a variation of LASIK, and is also called epithelial LASIK or E-LASIK. Epi-LASIK is used mostly for people in the higher refractive range where corneas are too thin or too flat for LASIK. In this procedure, a very thin flap is made consisting of the most superficial layer of the cornea (the epithelium). This is followed by the excimer laser treatment to correct your refractive error as in LASIK. At the end of the procudere the epithelial flap is put back and a transparent protective shield (bandage contact lens) is placed over the cornea. The epithelium takes a few days to heal following which the bandage lenses are removed. In the epi-LASIK procedure although the visual outcome is the same as that of LASIK, recovery of good vision takes 8-10 days. Your surgeon will be your best judge to decide which procedure you should undergo.



Q. Are both eyes treated at the same time?

Literature has shown that LASIK is an extremely safe procedure and sight-threatening complications are rare. Patients normally prefer to have both eyes treated at one sitting and get back to work faster. This practice is followed worldwide. However if the patient feels more comfortable getting only one eye treated at each session, this can be done without any additional cost to the patient.


Q. Will my number get fully corrected at the time of LASIK?

The laser is set so as to reshape your cornea to eliminate your number completely. However during the healing process the eyes of each person may heal slightly differently. Thus it is possible that you may have a small residual number. Usually this does not make it necessary for you to wear glasses for routine work.


Q. Are the results of the LASIK procedure permanent?

The correction of vision done by LASIK is permanent. However LASIK has no effect on the natural progression of your number. This is why we only perform LASIK in patients whose number has been stable for at least one year.

Q. If required, can LASIK be performed again?

If the objectives of visual correction are not met with in the first surgery, a second, or enhancement procedure can usually be performed to provide additional correction. Most people do not require additional surgery, but the higher the amount of correction necessary, the greater is the possibility of needing an enhancement procedure. The surgeon and the patient together assess this need and make the decision about further surgery.

Q. Will I require reading glasses?

After LASIK surgery you will be able to see all distant objects clearly. Since LASIK cannot arrest the normal aging process of the body, you may require glasses for reading at around 40-45 years. Sometimes it may be possible to correct one eye for distance and the other eye for near vision if you so desire. This is called monovision.

Q. Does LASIK correct all the problems associated with myopia ?

LASIK will only correct the refractive power of the eye so as to focus the image on the retina without need of glasses. However there are other associations and possible future risks in a Myope like higher chances of retinal detachment, glaucoma ,cataract, etc. LASIK does not change the risk of such problems in future. Therefore patient should always mention the past history of LASIK during future eye check-ups. Because it's difficult for ophthalmologists to detect the past occurrence of LASIK if it is not looked for. It is important that patient should get regular eye checkup with special emphasis on retina and glaucoma.