Frequently Asked Questions About LASIK Eye Surgery

How do the visual outcomes of IntraLase-initiated LASIK compare to traditional microkeratome initiated LASIK?

Clinical studies that have randomised patients to one eye with IntraLase LASIK and the fellow eye to microkeratome LASIK are the only scientifically valid way to compare the two techniques. These studies show that:

  • More patients achieve 20/20 or better vision with IntraLase-initiated LASIK.
  • Patients stating a preference preferred the post-operative vision of their IntraLase-treated eye 3-to-1 over their blade-treated eye.
  • IntraLase creates fewer high- and low-order aberrations, associated with night glare and halos.
  • IntraLase patients have a reduced incidence of post-operative dry eye symptoms.
  • IntraLase patients required fewer enhancement procedures following LASIK.
  • The precision of the IntraLase flap significantly reduces the incidence of post-operative induced astigmatism as compared to a microkeratome-created flap.
 

Is traditional microkeratome LASIK unsafe?

Not unsafe, but just higher risk. While traditional LASIK is a successful and relatively safe procedure, the IntraLase laser makes it safer by virtually eliminating the severe, sight-threatening complications of the microkeratome. IntraLase-initiated LASIK is not only 100 times more accurate, but it also provides patients with superior visual outcomes. These facts are giving thousands of patients each month the confidence to proceed with corrective laser eye surgery. Blade-free IntraLase LASIK has been approved for US Naval Aviators (Top Gun pilots) and by NASA for astronauts. Microkeratome LASIK is not approved for these visually demanding professions.
 

Is IntraLase more expensive?

Yes. Most patients agree that the added level of safety and better vision offered by IntraLase is worth the incremental cost. IntraLase surgeons are leaders in the field of ophthalmology who continually evaluate advances in technology. They’ve determined that the IntraLase is the most sophisticated and accurate system available today for flap creation and have invested in the technology to sustain their leadership in patient care.
 

How does the corneal flap affect visual outcomes?

New science reveals that the corneal flap has been widely underestimated for its affect on the visual outcome of LASIK. If the corneal surface is left with microscopic high and low spots, the precision of the excimer tissue ablation (step two) can be compromised. Eliminating even minute inaccuracies on the corneal surface improves the visual outcome of the procedure.

Surgeons have found statistically and clinically significant differences in the vision patients achieve when the IntraLase laser is used for corneal flap creation. The IntraLase FS laser goes beyond simply creating a safer, planar flap to preparing an optimal corneal architecture below the flap, providing for superior visual outcomes. The end result: fewer complications and better vision.
 

Will it hurt?

Topical anaesthetic drops are placed into your eye prior to treatment to numb the eye so there is usually no pain experienced during the procedure. You will be aware of some pressure against your eye. For several hours after the procedure you may experience a grittiness or irritation. This irritation lasts about 4 or 5 hours. Some people do experience mild pain after LASIK surgery that can be relieved with pain relief tablets.

There can be more pain experienced after PRK surgery than there is with LASIK. The measures we take to reduce pain after PRK include using soft disposable contact lenses, freezing the cornea with chilled balanced salt solution immediately after PRK and using eyedrops similar to aspirin.
 

Why I should choose to have LASIK at Fendalton Eye Clinic?

The care we take of you, the experience of the surgeon and the quality of the technology that we use.

  • Our staff care about giving you the best result for you as an individual.
  • Dr. Kent is one of the most experienced LASIK surgeons in Australasia. He has done more LASIK surgery than any other New Zealand eye surgeon. As with any surgical operation the more experience the surgeon has the less likely a complication due to surgeon error is.
  • We are the only clinic outside of Auckland that offers the greater safety, accuracy and superior results of blade-free LASIK using the IntraLase femtosecond laser.
  • We perform 100% personalised treatments so that every laser treatment is tailor-made to each individual eye.
  • The B&L Zyoptix 100 excimer laser has iris recognition technology and multidimensional eyetracking. The results of excimer laser surgery presented to the United States Food and Drug Administration, B&L Zyoptix produced better visual results and a lower complication rate than any other excimer laser in use in New Zealand.
  • We do everything we can to give you the best result possible. Follow up after LASIK at Fendalton Eye Clinic is for a full twelve months. Within New Zealand the cost of follow up appointments is met by Fendalton Eye Clinic. Enhancement surgery is free of charge within twelve months of the initial LASIK treatment. We do not have a rigid criteria for enhancement surgery. An enhancement will be done if it will improve your visual result and can safely be performed.
  • A database is kept of all of Dr Kent's results. Dr Kent constantly analyses LASIK results at Fendalton Eye Clinic.
  • We have a state-of-the-art purpose-built laser eye surgery theatre.
 

What is photodisruption?

The IntraLase femtosecond laser uses an infrared beam of light to precisely separate tissue. This molecular process is called photodisruption. Each pulse of the laser creates a tiny 2- to 3-micron bubble of carbon dioxide and water vapor. The focused laser pulse delivered divides tissue at the molecular level without the transfer of heat or impact to the surrounding tissue.
 

What ia a femtosecond laser?

A femtosecond laser generates light pulses as short as one quadrillionth of a second. Femtosecond technology has opened up a whole new area of scientific study, femtochemistry, which won the 1999 Nobel Prize in Chemistry. The application of the femtosecond laser in ophthalmology was developed by physicists, biomedical engineers and ophthalmologists at the Center for Ultrafast Optical Sciences and the Kellogg Eye Center, University of Michigan, USA. The IntraLase femtosecond laser has become the most accurate and safest technology for the corneal flap creation available today.
 

Has Dr Kent performed LASIK on other Doctors or any of the staff at Fendalton Eye Clinic?

Since 1997 he has has performed LASIK surgery on more than a hundred medical doctors and five optometrists. Dr Kent has performed LASIK on five of his staff members and two of his relatives. Dr Kent has also treated many national sporting representatives.
 

What is IntraLase initiated LASIK?

IntraLase-initiated LASIK (Laser In-Situ Keratomileusis) uses the IntraLase laser (a femtosecond laser) to complete the first step of the LASIK procedure. It is the latest advancement to make LASIK an all-laser procedure.

Noted for improving the safety and predictably of LASIK, the IntraLase laser replaces the oscillating microkeratome blade historically used in the first step. The IntraLase laser has also been proven to increase the chance of achieving normal 20/20 vision or better.

Today, the IntraLase laser is the technology of choice among most of the world's leading LASIK surgeons and at ophthalmic teaching institutions. IntraLase LASIK has been approved by both NASA and for US Naval Aviators (Top Gun pilots). Microkeratome LASIK is not approved due to the higher risk of complications and reduced quality of vision in low-light situations
 

What type of anaesthetic is used for LASIK?

LASIK is performed with topical anaesthetic drops placed in the eye to numb the eye. A mild sedative Lorazepam is also offered.
 

Who is not suitable for LASIK?

The following conditions are contraindications for LASIK.

  • rheumatoid arthritis
  • SLE
  • AIDS or HIV positive
  • a history of herpes simplex of the cornea
  • keratoconus
  • unstable or uncontrolled diabetes
  • pregnancy
 

Could I have PRK rather than LASIK?

If you have a low amount of myopia we still offer PRK. Some patients are safer to have PRK than LASIK due to a thin cornea. It is cheaper than LASIK and good results can be expected for low corrections. PRK has been shown to have no significant long-term complications. However even in very low corrections there is a longer time before clear vision is obtained after PRK.
 

Is there an upper age limit for LASIK?

Over the age of 60 years there is a high likelyhood that you will have early or mild cataracts. The best surgical option for correction of distance focusing problems is to have cataract extraction and intraocular lens implantation. 

In most cases we would use a multifocal intraocular lens such as the Alcon ReSTOR to given the best chance of seeing clearly for both distance and near vision without spectacles.
 

When treating both eyes at the same time is the same equipment used for each eye?

No. We do not compromise on quality. With the IntraLase a new disposable set up is used to treat each eye. 

Laser eye clinics in New Zealand that only offer microkeratome LASIK, almost always use the same microkeratome, same steel blade and same surgical instruments for both eyes. They only do this as this saves them time and money. Your eyes deserve better than this.
 

What about side effects such as transient light sensitivity and inflammation?

On rare occasions, some patients have reported transient light sensitivity (photophobia) at 2-6 weeks following IntraLase-initiated LASIK. This is due to an inflammatory response within the cornea. These side effects, while a nuisance, do not affect visual acuity and resolve with steroid eye drops. Almost all of these cases occurred with the older 15 and 30 kiloHeriz IntraLase models.
The incidence of light sensitivity has reduced almost to zero with the advent of the new 60 kiloHertz IntraLase used at Fendlaton Eye Clinic. In our first year with the IntraLase 60 KHz laser there were no cases of transient light sensitivity in 1000 cases.
 

Can I have both eyes done with LASIK at the same time?

Yes. It is safe to do both eyes one after the other, especially with the greater safety offered by blade-free all-laser LASIK. Dr. Kent has offered same day both eye LASIK since September 1997, the first New Zealand eye surgeon to do so.
 

How successful is the surgery?

We expect that 99% of those treated will be able to drive without glasses. About 90% of our patients achieve normal 20/20 or 6/6 vision without glasses. Sometimes those who had extremely high amounts of myopia (over -8.00D) may require glasses for night-driving or lectures.
 

Will LASIK mean I will never need spectacles again?

In rare cases a full correction may not be achievable, if you have a high correction and a thin cornea. We will discuss this with you at your initial assessment. This may mean that you will need to wear spectacles occasionally eg driving at night time. LASIK will not prevent your eyes from the normal ageing process.

There are some people who will have a change in their eyes with time. This can be either progression of myopia or hyperopia.

As with all people who have normal distance vision in both eyes you will require spectacles for reading at around age 45+. This aging of the eyes necessitating reading glasses at around 45+ in people with normal distance vision is called Presbyopia.

The only way to be independent of spectacles once you become presbyopic is to have monovision. Monovision is where one eye is treated so that it is fully corrected for the distance while the other eye is focused for near vision. If you are considering monovision as an option we would give you some disposable contact lenses to simulate what the surgery would achieve and get you to trial this for a week or two to determine for yourself whether or not monovision will suit your lifestyle. We would be happy to discuss monovision with you further. Please contact us directly.
 

Possible Complications of Corrective Eye Surgery

Minor Complications

  • Mild dry eye - Some people experience mild to moderate dry eye symptoms after LASIK. Occasional use of lubricating eyedrops may be required. Some people need to use these regularly. By 3-6 months the eyes are usually back to normal. We have found that dry eye problems are less common with IntraLase all-laser LASIK than with the older blade LASIK.

  • Undercorrection - If the refraction is not fully corrected and it causes a problem then an enhancement procedure can usually correct it, if there is enough corneal thickness to safely do more treatment. Enhancement treatments are generally done 3-6 months after the initial procedure, once vision has stabilised.

  • Overcorrection - An initial overcorrection is expected for high corrections and in hyperopia. It usually regresses in the first 3 months. If overcorrection persists then enhancement surgery can be done, if it is safe to do so.

  • Induced astigmatism - Can usually be corrected with enhancement surgery. Now very rare with IntraLase all-laser LASIK.

  • Regression - This results in undercorrection and can usually be corrected with enhancement surgery.

  • Light sensitivity - In the first few days some people will be sensitive to light. Delayed light sensitivity has been reported in the past with the IntraLase, but we have yet to have a case using the newer 60 kilohertz version.

  • Pain - About 5% of patients say they have some mild pain after LASIK that can be relieved with pain relief tablets and usually resolves by 4-5 hours.

  • Night vision problems - In the first few weeks following surgery about 20% may experience halos around lights at night time. This effect should fade. By twelve months this should only effect around 5%, generally those who started with a high correction.

  • Haze - Some eyes develop faint haze in the interface between the flap and corneal bed that is maximal at 3-6 months and fades away by 12 months. It is very rare for this to affect vision.

  • Interface debris - Minor debris in the interface is not uncommon. It very rarely affects vision and if it does can usually be removed.

  • Corneal abrasion during the procedure - In some people the surface layer of cells on the cornea are looser than average and can be dislodged resulting in a surface abrasion. Over the following 2-3 days the abrasion will heal. This is now extremely rare with the IntraLase.

Important Complications

  • Loss of best-corrected vision - Following surgery if the vision in an eye cannot be corrected with lenses to the same line on the eye chart as before the surgery then this is called loss of best-corrected vision. Anything that affects the optical quality of the cornea can cause it. At Fendalton Eye Clinic using the B&L Zyoptix 100 laser and the IntraLase the chance of this happening is currently about 1 in 1000.

  • Corneal ectasia (bulging) - If there is too much tissue removed from the cornea it may lose its structural strength and start to bulge outwards. It can be eliminated by careful measurement of the thickness of the cornea. This is extremely rare, probably less than 1 in several thousand. It is less likely to occur with the IntraLase than microkeratomes as the IntraLase flaps are more consistently thinner and hence leave more of the cornea untouched.

  • Progression from sub-clinical to true keratoconus (conical cornea) - This may occur if the most subtle signs of keratoconus are not detected with the corneal mapping (topography). With ORBSCAN II topography this is very rare, probably less than 1 in several thousand.

  • Severe dry eye - Occasionally the surface of the eye is very dry and remains rough and irregular for 6-12 months. Most will recover with time but very rarely will it persist beyond a year.

  • Epithelial ingrowth - Significant growth of the front cell layer (epithelial cells) between the flap and the bed. This occurs in less than 1 in 2000 eyes.

  • Diffuse lamellar keratitis - In rare cases there is movement of inflammatory cells into the interface between the flap and the bed. This can rarely result in the cornea becoming an irregular shape. Severe cases that affect vision occur in about 1 in 2000 cases. Most resolve with time.

  • Infection - Infection in the cornea following LASIK is extremely rare, about 1 in 10,000 cases. We have had only one case in over 13,000 LASIK surgeries which quickly responded to antibiotic eyedrops and resolved without complication.

  • Problems cutting the flap - "Partial flaps", "Irregular flaps" or "Buttonholes" are all cases where a perfect flap is not achieved. The chance of this occurring with a microkeratome is about 1 in 500. The IntraLase almost completely eliminates the chance of making a less than perfect flap and has never been reported to produce a buttonhole flap in more than a million eyes.
 

What are the long-term complications of LASIK?

The most serious long-term complication of LASIK surgery has been keratectasia. Keratectasia is progressive thinning and distortion of the cornea resulting in anything from mild to severe astigmatism. This can occur when the early stages of "conical cornea" or keratoconus are not detected prior to surgery. The Orbscan II at Fendalton Eye Clinic is the most sensitive method currently available for detection of early keratoconus or subtle abnormalities of the cornea. All eyes treated at Fendalton Eye Clinic have an Orbscan prior to LASIK.

We offer surface ablation treatments (PRK) for anyone who we think should not have LASIK.

Using the IntraLase we can make thinner more even thickness flaps than any microkeratome can. Microkeratome flaps of the same central thickness are much thicker peripherally than an IntraLase created flap. This means that a microkeratome created flap removes more tissue from the peripheral cornea than the IntraLase does. Consequently, we consider the blade-free technique to be much safer for the long-term mechanical stability of the cornea.
 

How long has LASIK been done for?

LASIK using a microkeratome was first performed in Europe in 1991 and in New Zealand in 1995. IntraLase LASIK was first performed in the USA in 2001 and in New Zealand in 2006.
 

Can I go blind?

The risk of blindness from LASIK surgery is almost zero. An eye could become legally blind if there was a very bad eye infection after the surgery, which was unable to be controlled with antibiotic drugs. If such a serious complication did occur, then it would normally be possible to perform a corneal transplant and restore sight to that eye. This has never occurred in New Zealand.

In order to minimise any chance of infection at Fendalton Eye Clinic we prepare the eye with povidone-iodine and use a sterile drape around the eye. We also use antibiotic eyedrops. The chance of an infection with IntraLase LASIK is very low as no surgical instrument touches the cornea to make the flap.
 

What is an 'enhancement'?

Enhancement surgery is additional treatment to "fine tune" the result. It takes one to three months from the initial surgery for the vision to be stable. During this time there may be some minor fluctuations in your vision. There is a lot of individual variation in the rate and amount that people heal. If after three months there is some under or over correction Dr Kent can offer you some additional lasering to optimise the outcome, providing it is safe to do so.

Enhancement surgery involves lifting the existing flap using fine surgical instruments to identify the edge of the flap and lift it to perform additional lasering. Generally enhancement surgery is more likely in higher or more complicated corrections. Enhancements are only needed in about 1% of cases of low short-sightedness. For higher corrections (over -8.0) there is a greater chance that an enhancement may be required. The overall rate of enhancement surgery following LASIK is about 4%. Enhancements are done free of charge within twelve months of the initial procedure as we want you to be happy with the final outcome.
 

What are the main side effects of LASIK?

  1. Dry eyes - For the first few weeks following surgery your eyes may be dry. This may be evident as a fluctuation in your vision or a gritty feeling. Dry eyes are alleviated by lubricant drops. The amount and duration of time that your eyes will require lubrication for is difficult to predict. If you suffered from dry eyes prior to LASIK you can expect that you will be required to use lubricant drops more frequently following your treatment.
  2. Over correction - Immediately following your LASIK treatment there is usually some over correction. As your eyes heal over the first one to three months following your treatment this overcorrection resolves. It generally takes between one to three months for your vision to stabilise. If you are bothered by residual under or over correction after three months enhancement surgery will be offered to you if it is safe to do so.
  3. For the first couple of weeks immediately following LASIK some people notice halos around lights at nighttime. This goes away over the first 4 - 8 weeks after the surgery as your eye heals. Permanent night vision problems such as halos and glare are rare, and this can occur in people with very high amounts of myopia over -8.0. In order to treat high corrections the treatment area has to be reduced. We check your pupil size and corneal thickness at our introductory assessments, and can tell you if this is likely to occur in your case.
This is not an exhaustive list of side effects. Other rarer side effects will be discussed with you prior to your surgery.
 

Can the flap be dislodged?

During the first few weeks after the surgery you do need to be careful of your eyes, as a sharp object in your eye could possibly dislodge the flap. If the flap did get dislodged, then it can be repositioned.

After six weeks the flap is well healed. The chance of the flap being dislodged at this point is remote. It would take an event that would otherwise cause a severe injury to your eye to cause a problem with the flap after six weeks.
 

How does the flap stick down?

The flap adheres back to the eye without the need for stitches. It is held in place until it heals by the natural stickiness of the inner layers of the cornea in combination with the "suction" effect of the back layer of cells (endothelium) of the cornea. Within four hours the front layer of cells (epithelium) heal over. We ask you to wear clear eye-shields after the surgery and overnight so that your eyes are not accidentally rubbed or bumped in the initial healing period.
 

How can I keep my eye still and not blink during the surgery?

Your eye is held open by a speculum that makes it impossible to blink. There is a small bright red "fixation" light for you to look at during the surgery this ensuring that your eye is in the correct alignment for the excimer laser treatment. The total time of the lasering portion of your treatment is only 10 - 70 seconds, depending on the correction being treated. At any point if your eye moves then Dr Kent is able to immediately stop the laser and then continue exactly where he left off once the eye is realigned.

The Bausch & Lomb Zyoptix 100 excimer laser that we have at Fendalton Eye Clinic has a very fast and accurate active Eyetracker. The eyetracker response time is 6.5 milliseconds and it tracks the eye in all 3 dimensions.
 

How long do I have to be out of my contact lenses prior to LASIK?

Contact lenses can affect the natural curvature of the cornea. You will be required to cease wearing contact lenses for a period of time leading up to your LASIK treatment. This period without contact lenses allows the cornea to return to its natural state, which will optimise the treatment outcome. The period without contact lenses depends on the type of contact lens that you are wearing.

Soft daily wear or disposable contact lenses should not be worn for 12 days before surgery.

Soft toric (astigmatism correcting) contact lenses. This type of contact lens "moulds" the cornea more than a standard soft contact lens. Therefore we advise you to cease wearing soft toric contact lenses for three weeks prior to your treatment.

Hard or rigid gas permeable (RGP) contact lenses. This type of lens maintains its own shape while on your eye. They therefore have a greater moulding effect on the cornea. You will need to cease wearing hard or RGP lenses for 6-8 weeks prior to your surgery.

If you do not have spectacles we may be able to supply you with a loaner pair that will be close to your prescription to assist you during the period that you are required to be out of contact lenses.
 

Do I have to take much time off work?

Normally we ask that you have a quiet day the day after the surgery. Most people have their surgery on a Thursday or Friday, and are back at work on Monday. You should relax completely immediately after the surgery.
 

What day of the week can I have LASIK?

Dr Kent does LASIK surgery on Thursdays most weeks. Occasionally throughout the month other days are available such as Monday or Friday. If you are from outside of Christchurch it may be possible to have your initial assessment with Dr Kent in the morning with your LASIK treatment on the same day in the afternoon. Please contact the clinic directly for the day that best suits you.