Few Facts about Lasik-Refractive Surgery to remove Spectacle Power?
(Are you a good candidate for LASIK?)

If you're tired of wearing glasses or contact lenses, you may be considering Lasik Eye Surgery — one of the finest procedures to correct Spectacle Related Vision problems. Lasik option creates doubts & queries, so before you sign up for the Surgery, this article will help you get a clear picture of whether it is a good option for you or not and what you can expect.

Dr. parul sharma

Femto Lasik & Cataract OT

Understanding Your Eyes?

To see clearly, light rays have to focus on the retina — a layer of light-sensing cells at the back of the eye. The retina converts the light rays into impulses that are sent to the brain, where they are recognized as images. If the light rays focus either in front or at back of retina , the image you see is blurry. This is called a refractive error. Glasses, Contact Lens and Refractive Surgery attempt to correct these errors by making light rays focus on the retina.

Dr. parul sharma

PreLASIK Scanning platform

What is Lasik?

Lasik – Laser Assisted In Situ Keratomelieusis is a procedure by which the front mirror portion of Eye called Cornea is reshaped by laser to nullify Spectacle Power. The result of procedure is based on highly sophisticated computerized automated machine. A thin flap of Cornea is raised by microkeratome or Femto laser , and then a highly precise excimer laser is delivered on Cornea bed to reshape cornea at a microstructural level to correct refractive error,after which the flap is put back. There are no sutures or pain involved. It is a short duration walk in walk out procedure.

Dr. parul sharma


Am I a suitable candidate for Lasik?
  • You should be at least 19 years old.
  • Your Refraction ( glasses power) should have been stable for more then a year
  • You will have to undergo detailed Eye examination to decide if Lasikis Suitable for your Eyes - Corneal Thickness, Eye Pressure, Retina Examination etc.
  • You should not be Pregnant or Nursing as these conditions might change the measured Refraction of the Eye. It is best to wait for 6 months after delivery to get Lasik done.
  • You should be in good general health. Lasik may not be recommended for patients with Diabetes, Rheumatoid Arthritis, Lupus.
  • You should not have eye Diseases like Keratoconus, Glaucoma, Herpes Infections of the Eye, severe Dry Eye.
  • Understand your expectations from the Surgery. Are they realistic? Discuss all the pros and cons in detail with the Surgeon.
Dr. parul sharma

3D OCT Topcon

Can any Power be Corrected?
  • Myopia -1 to -8 can be safely treated. However with modifications in procedure and using advanced versions of software, powers upto -12 can be removed, These days we prefer to treat myopia above -8 to -20D with Phakic ICL implantation.
  • Hyperopia +1 to +6
  • Astigmatism 1 to 6
Dr. parul sharma

PreLASIK Zywave -aberrations & Zyoptix planning

How is Lasik Done?

The procedure is done under topical anesthesia, ie, drops are used to make it painless. A hinged Corneal flap of 90 to140 um and 7.5 - 9.5 mm diameter is raised using a high precision instrument called microkeratome (high oscillating blade) or Femto (bladeless). Excimer Laser is then applied to the exposed stromal bed to reshape cornea as per the spectacles power.The flap is replaced, interface is washed and allowed to dry. This gets re-attached in few mins without any stitches. Thus there is virtually no wound and the patient is able to leave operation theatre without any pain, pad or bandage.

Dr. parul sharma


How Long does the Surgery take?

The procedure takes around 15 min, the actual laser treatment time being in seconds. It is a walk in walk out procedure with no Eye pad or bandage. Most of the patients resume normal activities next day.

Dr. parul sharma

Preparing Excimer Laser Machine

How Safe is the Procedure?

Lasik is quite a safe procedure now. The high end Lasik Machines, Microkeratomes,Femto laser, advanced softwares, topo guided treatments etc have made this possible. One has to ensure that all selection criteria are meant. We are very stringent on that and if there is the slightest doubt of unpredictable result in an individual Eye, we motivate the patient to keep wearing his glasses or Contact Lens. Complications such as overcorrection, under correction, regression, inflammation, corneal haze, epithelial ingrowth, rarely flap related issues , ectasia and very rarely infection have been reported in literature across the world, but are few .Most of these can be managed well with timely intervention.

Dr. parul sharma

Lasik Planning-right eye

How Soon Does one Attain Visual Recovery following Lasik?

The visual recovery happens within a day and the fine focussing in 5-7 days. People resume work after 2 0r 3days. The post-operative eyedrops are required for 3-4 weeks, in reducing dosage. Initially there may beglare while night driving which settles down in few weeks.

Dr. parul sharma

Lasik Planning -left eye

What is the long term effect of this procedure on one’s Eye?

As much clinical data we have, shows that it has no side effects on other parts of eye in long term. The laser is done on front surface of the cornea and the studies have shown no effect on endothelium i.e. the back surface of cornea. It is important to keep the details of your original corneal mapping / scans as these will help to calculate correct lens power if you ever undergo cataract surgery in future.

Does the Correction Obtained after Lasik Last a lifetime? Is it true that I will not require any glasses whatsoever in future?

Yes, if the eye does not suffer any other disease and the corneal biomechanics are good, no glasses would be required. Few patients ,specially with high powers may have mild regression which means small powers coming back after few years. . Also the presbyopic changes will require you to wear reading correction around 45 years of age.

Can people between 40 & 60 yrs of age also get Lasik done?

Sure, they can. Though if you are above 45 yrs of age, Lasik can correct only your distant vision but you will still nead reading glasses as & when required.

What is the difference between LASIK & Femtobladeles LASIK?

Bladeless FEMTO LASIK: Any LASIK procedure basically has two main steps, first is to create a very thin CORNEAL FLAP (can be created either by blade-microkeratome or bladeless-femtosecond laser) and then treat-ablate the remaining corneal bed by EXCIMER Laser to reshape the cornea in order to nullify spectacles power.

Hence it is only the first step of creating flap which is different in blade and bladeless Lasikthe rest procedure of glasses correction by Excimer Laser is same in both.

FEMTO Laser :A Femtosecond is one millionth of a nanosecond or 10 -15 of a second and is a measurement used in laser technology.The femtosecond laser is used to create flap of cornea with varied specifications, which gives the surgeon more control, precision and increases the SAFETY FACTOR:

• Flap Shape – Planar (better then microkeratome flap) • Good Visual Procedure Control • Customised: Flap Thickness &Diameter Control –By Computer • Cut Pattern - Raster/Spiral • Side cut angle can be customized to 90 –prevents epithelial ingrowth, decreases chances of epithelial folds, allows snug fit of flap on cornea bed. • The suction ring creates an intraocular pressure (IOP) of approximately 40 mm Hg which is lower then created by microkeratome -60mmHg,hence safer for patients with ocular hypertension or borderline well controlled glaucoma patients. • The uniform thickness and vertical cleavage plane fits the flap like a manhole cover on stromal bed, minimizing the chance of flap slippage or wrinkling if accidentally rubbed or bumped during healing after surgery. • If the surgeon encounters a loss of vacuum during flap creation with the femto laser, the flap creation can be repeated immediately with no known adverse affect. • Because the femto laser software enables the laser to produce flaps with vertical edges, it is more difficult for epithelial cells to migrate down under the flap into the interface since the length of the route for those cells is increased.


1. Reduced incidence of flap complications like buttonholes, free caps, irregular cuts etc 2. Greater surgeon choice , customization and control over flap diameter and thickness, side cut angle, hinge position and length 3. Increased precision with improved flap safety and better thickness predictability 4. Capability of cutting thinner flaps to accommodate thin corneas and high refractive errors 5. Absence of moving parts 6. stronger flap adherence, decreased incidence of epithelial ingrowth under flap 7.less increase in IOP –so better for ocular hypertension & borderline glaucoma cases. 8.lesser incidence of dry eyes 9. Loss of suction during FS laser LASIK flap creation is easier to handle and the suction ring may be reapplied and treatment resumed immediately in many cases

PATIENTS GAIN CONFIDENCE: The higher degree of comfort and safety, virtually almost no risk of complications, and more predictable outcomes increase patient satisfaction in their experience and outcome. Patient Comfort is good as surgical procedure is fast hence there is no trauma to the eye and patients tend to be very relaxed during the procedure.

However, the technique presents with its unique set of disadvantages and related complications:

1. Opaque bubble layer (OBL): Gas bubbles routinely accumulate in the flap interface during FS laser treatment.Rarely. central vertical gas breakthrough may potentially result in a flap buttonhole. If this happens then the surgeon would not continue the procedure and lan it 3months later and cut the flap at different thickness. 2. Transient light sensitivity syndrome (TLSS): present with photophobia and good visual acuity .It resolves andmay require topical steroids eye drops for few days. 3 Lamellar keratitis may happen but usually resolves with minimal sequelae. 4.Femto laser flaps are slightly more difficult to lifet in case of retreatment required. 5.increased cost due to added machine cost.

Studies have shown FS laser to be safer but the visual and refractive outcomes of FS laser LASIK are equivalent to microkeratome LASIK. In most eyes , the microkeratome with standard Proscan or Zyoptix works as well as Femto laser. The femto laser offers advantages of more precision, option of customization and increases safety factor in some eyes. Your surgeon will guide you as to which procedure is better for you after examining your eyes.

The total cost of Bladeless Femtosecond LASIK -90,000/-for both eyes.

Standard LASIK (Proscan) – 50,000/- for both eyes

ZYOPTIX LASIK –60,000/- for both eyes