By Dr. Venkatesh Prajna, Dip NB

Who can benefit from LASIK?
If LASIK is not performed, will the refractive error increase progressively?
Can the refractive power become exactly zero?
What are the requirements before coming for preoperative evaluation before LASIK?
What are the preoperative evaluations usually performed before doing LASIK?
How does LASIK work?
Is LASIK painful?
What are the postoperative instructions following LASIK?
When can one start watching TV or computer monitor?
What are the complications of LASIK?
What are the options available for residual power following LASIK?

With the advent of the excimer laser, refractive surgery is opening up new life style choices to people who were previously dependent on spectacles or contact lenses for clear vision.

LASIK laser technology allows for an unparalleled degree of precision and predictability of outcome, and is the outpatient surgical technique of choice for the treatment of myopia, astigmatism and hypermetropia (short sight and long sight). It is fast gaining in popularity, both in India and around the world. Over a million people have undergone LASIK procedure all over the world. The technique has been well proven to be safe and effective with excellent results since its introduction from 1989.

Here are some of the often-asked queries about LASIK.

Who can benefit from LASIK?

The ideal candidate for LASIK is anybody above 18 years of age without any major eye disease. In addition to having a healthy cornea, patients must not have had a significant change in their glass prescription in the last 12 months. People with certain conditions like steep cornea, opaque cornea, severe diabetes, glaucoma and cataract may not be good candidates for LASIK.

No. Irrespective of whether LASIK is performed or not, the progression of refractive error after the age of 20 is negligible in a majority of the population. If you are comfortable with your glasses or contact lenses, there are no additional benefits in undergoing this procedure.

Even though there is a high chance for the refractive power to become zero, especially in lower and moderate myopia (up to –6 Diopters), no person can be guaranteed to get exactly a zero power. Since the rate of healing response differs from individual to individual, there may be mild interpersonal variations between individuals, even if they are being treated for similar degrees of refractive error. Even though LASIK can eliminate glasses in a significant majority of persons, the primary aim is to reduce the dependence on optical aids like glasses or contact lenses.

Contact lens wearers have to discontinue wearing them at least a week before coming for preoperative evaluation, since the usage of contact lenses may interfere with certain preoperative evaluations like topography.

1. Refraction: A detailed subjective refraction is performed to determine the precise refractive error ( Tests that you usually undergo when glasses are being prescribed)..

2. Keratometry: is a test performed to measure the corneal curvature and is especially useful for patients with astigmatism.

3. Pachymetry: is a test used to measure thickness of the cornea, which is performed to ascertain whether the cornea is thick enough to withstand laser treatment.

4. A complete retinal examination is performed. If the retina is found to be having any degenerative changes, the same is treated first using a barrage laser and after a month, LASIK laser is performed.

There are essentially three steps to LASIK surgery.

• A thin layer of the cornea of uniform thickness is created using a special device called microkeratome. This flap is then raised to expose the inner layers of the cornea.

  

• The pre-programmed excimer laser is then used to reshape the bed of the cornea, with exact precision of sculpting, to make the required correction.

  

• After sculpting, the corneal flap is repositioned without any suturing.

  

The procedure is generally painless. Anaesthetic eye drops are instilled half an hour prior to surgery. No injections or sedations are necessary.

Immediately following LASIK, the patient is seen by the ophthalmologist to see for the placement of the flap. The patient is instructed to keep his eyes closed preferably for a period of 4 – 6 hours. After this time period, he can move around inside the house wearing protective goggles. The patient is examined in the following day and a preliminary refraction is performed. After this time period, he/she can resume normal indoor activities. The patient is instructed to use eye drops for a period of 1 week.

One can watch TV or computer monitor, after the first postoperative day. You may have some glare for around 10 –15 days, for which you can use a protective screen in front of the computer monitor.

LASIK is usually a very safe procedure. Even then, serious complications like infections and progressive thinning has been reported in the literature, but they are very very uncommon.

1. If the power is very small and the patient is able to do all his/her routine works, there is no need to wear any spectacles or contact lenses.

2. If the patient finds difficulty in day to day activities, then he can wear light powered glasses. Contact lenses should be avoided, as much is possible.

LASIK is a relatively simple eye surgery and is performed in an operation theatre set up. All sterile steps are strictly adhered to, to prevent infections. Even though it is a simple operation, the decision to undergo this should clearly depend on the needs and expectations of the patients themselves.

Dr N Venkatesh Prajna is the Medical Officer, Cornea Services, Aravind Eye Hospital, Madurai. He is also a Reader, Cornea Clinic. For further information you may contact:

Lasik Centre

Aravind Eye Hospital

Madurai 625 020

Email:lasik@aravind.org

Phone: 0452 – 5356100 (30 lines)

Fax: 0452 – 2530984