Laser Eye Sugery
Glasses and their Alternatives
Laser Eye Surgery is a relatively new process. For hundreds of years glasses have enabled people to see clearly. In recent decades contact lenses have been used successfully by millions of people. Many people are happy with these two methods of managing their visual needs, and don’t need to consider laser surgery to their eyes. Others however find strong glasses produce distortion, or they may feel uncomfortable in glasses. Other patients find contact lenses troublesome or intolerable due to sensitivities or allergies. It is these groups of patients who consider that surgical treatment of their refractive errors may be desirable.
In the 1970′s and 1980′s radial keratotomy (“the Russian Operation”) received some public attention. It worked by cutting spoke like incisions into the edge of the cornea in order to flatten it centrally.
Cataract surgery can also eliminate short-sightedness by replacing the eye’s natural lens with a weaker implant lens. This procedure is usually reserved for patients with cataracts, however a similar technique called Clear Lens Extraction can be used to achieve similar results in suitable patients. As the procedure is more invasive than Excimer laser there are small risks of retinal detachments and infection following surgery within the eyeball.
Other refractive surgical procedures that are developing and practiced in much fewer numbers than Excimer Laser include phacic implant lenses, intrastromal corneal rings, and radio frequency tightening of the cornea.
How Does the Excimer Laser Work?
Excimer laser eye surgery has revolutionised the treatment of shortsightedness , longsightedness and astigmatism since the early 1990′s.
In 1983 scientists first used the Excimer Laser to engrave plastic, and an American ophthalmologist named Dr Steve Trokel later realised that the laser could be used to re-shape the cornea, thus overcoming the need for some patients to need glasses.
The name originally given to the correction of refractive errors with laser applications to the surface of the eye is Photorefractive Keratectomy (PRK).Excimer laser works by sending brief pulses of ultraviolet light onto the cornea. The light’s energy breaks apart molecules on the very surface of the cornea. Each pulse removes one quarter of one micron of tissue (it would take four thousand pulses of laser to pass through one millimetre of tissue). The laser gradually sculpts the cornea to the desired shape.
“this microscopic picture of a human hair with ridges cut into it with a Excimer laser demonstrates the precision of the laser in removing minute amounts of tissue”
The removal of 10 microns of corneal tissue corrects one dioptre of myopia. This is an extremely small change to the corneal thickness. (As a comparison, a human hair is 50 to 100 microns thick).
Since the mid 1990′s the excimer laser has been used to reshape the cornea after a flap of tissue is cut, this is called LASIK.
What is LASIK?
LASIK is a modification of Excimer refractive surgery. A thin flap of tissue is made in the cornea prior to applying the Excimer laser.
The flap is very thin (110-120 microns). Dr Cherny now uses the Intralase system to create the flap without the need for a surgical blade. He believes this is a safe and more controlled technology. Intralase is a more expensive technology than the blade LASIK, but Dr Cherny believes it provides a safer and more accurate result.
The flap is still attached to the eye at its edge, so that it can be folded back into position after the laser has been applied. Overnight the flap secures itself by healing across the surface cells at the edge of the flap. Patients can return to most normal activities the next day and the procedure has very little discomfort for almost all patients.
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| The Intralase laser creates microscopic bubbles to form the flap. |
After the corneal flap is formed the laser is delivered to the cornea |
What are the Advantages of LASIK Compared to PRK Laser Treatment?
The short-term advantage for the patient is that the eye is less painful after LASIK than after PRK, the visual recovery is faster and eye drops are usually only needed for one week.
The long term advantages of LASIK include reduced risk of scarring and increased stability of the vision for higher levels of myopia. Stable vision returns faster after LASIK, and eye drops are usually only needed for one week.
The long-term disadvantages of LASIK include potential complications relating to the creation or healing of the flap.
The flap may be incorrectly formed, or material (dust, germs, and cells) can theoretically become trapped under the flap.
Lasik is slightly more expensive because it requires additional technology to create the flap.
A large proportion of excimer laser patients are now treated with Lasik rather than PRK.
Dr Cherny can discuss with each patient the relative advantages and disadvantages of LASIK in their individual situation.
“I have been told I should have PRK or ASLA”…
Dr Cherny is proud that his laser eye surgery centres in Melbourne offer both PRK (ASLA) and LASIK, and Dr Cherny advices each patient as to which will give the safest and best results.
A WORD OF CAUTION:
Patients should be aware that not all centres performing laser eye surgery have equipment for Lasik or Intralase. Sometimes the terms ” Blade-Free” and “Flap” are used in reference to PRK (ASLA), but this is NOT Lasik .
Dr Cherny cautions patients to ask any centre offering them surface treatment (PRK or ASLA) to clarify if that is the ONLY laser option available at the centre. You might want to ask …. “Do you offer Intralase and how many Lasik treatments were done here in the last year”.
We believe some patients are best treated with LASIK, to reduce the risks of corneal scarring and to aid with the accuracy of treatments.
We believe many patients are not aware that some centres do not have the technology to deliver Lasik , one of the most commonly performed and respected treatments internationally.
Many patients also prefer LASIK because of the increased speed of healing, rapid return to normal activities, and almost total absence of pain.
When Is Excimer Laser Surgery Considered?
Excimer Laser Eye Surgery (either PRK or LASIK) can be considered in the following circumstances:
1. For those patients with short-sightedness or astigmatism who desire to be more independent of their glasses and contact lenses.
2. For those patients who cannot use glasses or contacts because of their occupation, or due to their recreational interests (e.g. swimming, yachting, scuba diving, skiing etc).
3. For those patients who find thick spectacle lenses to be visually or socially restrictive.
Dr Cherny will be able to answer any questions you may have regarding the advantages and disadvantages of Excimer laser surgery.
How Does the Normal Eye Work?
In simple terms the eye is like a camera. Light hits the eye at the cornea. The cornea is the clear “windscreen” of the eye. As you look at an eye the cornea appears to be the “colored part”, because the iris (which is colored) sits directly behind the cornea.
The cornea is in fact the major part of the eye that focuses light onto the retina. A structure called the lens sits inside the eye and completes the focusing of light, allowing a sharp image to appear on the retina. The retina turns the image into nerve signals which are passed by nerves to the brain.
What are the Reasons People Need Glasses?
What Is Short Sightedness?
Short-sightedness is also called MYOPIA. People who are short-sighted can see clearly at close range, but when looking across a room or down a street everything is out of focus. The optical reason for myopia is that the light rays come to focus before they reach the retina.
Optics of a shortsighted eye
This is caused by the cornea being too curved, or the eyeball being too long. Often myopia runs in families. Myopia will often be first noticed in childhood and progress until the early twenties.
Short-sightedness is measured in dioptres, and is recorded on a prescription for glasses or contact lenses. Low levels are 0-5 dioptres. High levels are 5-10 dioptres. Extreme levels are more than 10 dioptres.
What is Astigmatism?
Astigmatism exists when the cornea is slightly egg shaped instead of being regularly curved like a table-tennis ball. Objects appear blurred for both near and distance as the light rays entering the eye do not come to one single point of focus. Most people have some degree of astigmatism.
What is Hypermetropia?
Hypermetropia, otherwise known as long-sightedness, occurs in eyes that have a cornea that is too flat, or theoretically that the eye is too short. When a near or distant object is viewed, light enters the eye and comes to a point of focus somewhere behind the retina, rather than directly onto the retina. Hence near and distance vision is blurred.
Optics of a longsighted eye
What Happens as I Age?
What is Presbyopia
This is the normal loss of near focus that develops in all people who and begins at around the age of 45. It is related to the normal hardening of the lens in the eye, and the natural focusing power of the lens is gradually diminished. People with refractive errors (short or long sighted) who have laser treatment and obtain normal distance vision, will still go through this normal aging process. Therefore reading glasses will still be needed at around the age of 45, even after laser treatment.
A compromise system called monovision may suit many patients, allowing both near and distance vision without glasses.
What is Monovision
In monovision, one eye is treated to give sharp distance vision, and the other has a smaller treatment (or sometimes no treatment at all) and remains focused for near tasks.
Using both eyes together the brain mixes the signals from the two eyes, aiming to give comfortable near and distant vision. This arrangement can reduce or eliminate the need for reading glasses after the middle forties. It is a compromise arrangement, but one that can give the greatest number of years of freedom from glasses.
Dr Cherny likes to demonstrate this arrangement to his patients with lenses so that they can choose between monovision treatment, and full correction of both eyes. Many patients do not feel comfortable with monovision and choose to have both eyes corrected for distance, and will use glasses for near tasks after age 45. However a large proportion of Dr Cherny’s patients choose to have monovision treatment, and find they can then do most tasks comfortably for both distance and near without glasses, even after age 45.
Who is Suitable for Excimer Laser Surgery
Dr Cherny’s general guidelines are:
- Patients should feel that they are not content with the options of glasses and contact lenses.
- Age minimum is 21 years.
- The glasses prescription should be stable for at least 12 months.
- Patients with myopia, hypermetropia (or hyperopia) or astigmatism can be considered for treatment.
- Patients must be prepared to pay the costs of treatment as there is usually no rebate from Medicare or health insurance.
- Patients must understand the nature of the treatment, the risks and benefits.
- Patients must agree to attend appropriate post operative follow up visits.
- Patients must have eyes that are otherwise healthy, and must have a cornea of suitable thickness.
- Patients must have a refractive error that Dr Cherny believes has a high likelihood of being successfully treated.
- Patients must have realistic goals and expectations of the treatment.
Is Excimer Laser Treatment Covered by Private Health Insurance?
Usually not, but patients should check with their insurance company to find out if a rebate exists. Many patients may receive a taxation rebate.
Do I See Dr. Cherny Personally?
Yes, each patient’s specific details will be discussed in depth with Dr. Cherny to assess their suitability for laser surgery, and patients are given multiple opportunities to ask Dr Cherny any questions they may have.
What are the Clinical Results?
The vast majority of Dr Cherny’s patients are happy with their short, medium and long term results.
Millions of patients have been treated with Excimer laser surgery worldwide over the last 20 years. Follow-up studies continue.
To date severe long term complications have been rare.
If too much corneal tissue is removed progressive thinning and distortion of the cornea can occur (ectasia). Measuring the corneal thickness before treatment and calculating the amount of cornea that will be left behind reduces the risk of this complication.
Almost all patients find that they are much less dependent on glasses. Most patients find they no longer need to use glasses or contact lenses other than non-prescription sunglasses, unless they are over age 45 who require reading glasses.
Very few patients still need to wear glasses or contact lenses regularly to achieve vision good enough for comfortable driving and television viewing.
It is rare for a patient to feel that their vision has been made worse as a result of the treatment.
It must be emphasised that most people will need to wear reading glasses for fine, near work when they get older, unless they have chosen a monovision treatment.
What are the Steps I Must Take to have the Procedure Performed by Dr. Cherny
- Information Session with Dr Cherny (Free)
- “Check-up” session where eye drops are used and a full eye examination is performed by Dr Cherny (Free) This can be combined with the information session. This usually takes approximately 2 hours.
- The treatment. You will be at our centre for approximately 90 minutes.
- Follow up visits the next day then after 1 week, 1, 6 and 12 months (included in the cost of treatment if performed in Dr Cherny’s office)
Information Session
Dr Cherny holds regular free information sessions on Laser Eyesight Correction. This is sometimes held in a small group format. The sessions last about one hour, and patients have the opportunity to ask him questions about the treatment options. The information session provides a good understanding of Excimer Laser surgery, its benefits, alternatives and complications. There is no obligation to make any commitment to laser eye surgery.
“Check-Up” Sessions
Patients who have attended an information session and wish to undergo surgery next attend for a private consultation and examination session. Eye drops are used to open the pupil, and the patient can not drive for 2 hours after this assessment.
Soft contact lenses need to be removed one week prior to the visit, and rigid gas permeable lenses must be left out for four weeks. After the work up examination contact lens wear can be recommenced. All contact lenses must be discontinued one day prior to surgery.
What to Expect on the Day of Treatment?
The treatment is a walk-in, walk-out procedure.
A friend or relative who can provide transport after the procedure should accompany the patient.
Patients spend approximately 90 minutes in the building, but only twenty minutes in the treatment room.
Anaesthetic eye drops numb the eye.
The patient is positioned on a bed with the eye to be treated under the operating microscope
The other eye is covered during the procedure.
A clamp holds the eye lids gently open
Before the actual treatment the patient is familiarised with the way in which the laser will work
When all is ready Dr Cherny performs the treatment using the laser to reshape the cornea and create a flap with the Intralase machine when Lasik is being performed.
The patient can see a flashing light in the microscope, and must look straight at the flashing light.
The actual laser delivery lasts only 20 to 60 seconds, during which time the patient must look at the fixation light
There is no pain from the laser
Most patients find the treatment is not uncomfortable, and cope easily with the procedure.
After Excimer Laser Surgery
After treatment a clear plastic cover is put over the eye.
The patient cannot drive, and must return home to rest for the entire day until the next morning. Most Lasik patients can drive to the check up the next morning then go to work. Often there will be some red bruising on the white of the eye that settles over 10 days.
PRK patients require some additional checks during the first week after surgery.
PRK patients may experience some discomfort during the first 24-72 hours after treatment due to the removal of the surface layer of the cornea.
If Lasik is performed there is usually no pain, only a mild irritation.
Post-operative medication, such as analgesics, will be supplied to help ease any discomfort.
Most patients are reviewed the day following surgery , then after 1 week, 6 months and 12 months after surgery.
Is it Safe?
With millions of treatments having been performed internationally over more than 20 years, laser eyesight correction is now a most commonly performed medical procedure., Many leading eye surgeons around the world are delighted with the results of this treatment, and are optimistic that it is safe in the long term. However, as with any surgery, complications are possible. Whilst there is over 20 years follow up with PRK and 15 years follow up with LASIK internationally, it is impossible to rule out long term complications that may not yet be recognised.
It is important patients have a full understanding of the risks as well as the benefits.
Here we provide you with an extensive lists of the potential complications;
What are the Possible Side-effects and Complications of Excimer Laser Surgery?
Many leading eye surgeons around the world are delighted with the results of this treatment, and are optimistic that it is safe in the long term. However, as with any surgery, complications are possible. Whilst there is over 20 years of international data and experience of follow up with PRK and 15 years follow up with LASIK , it is impossible to rule out long term complications that may not yet be recognised.
The following possible side effects and complications should be considered:
- Overcorrection
Uncommonly, the eye may become overcorrected and be far-sighted rather than shortsighted.
- Undercorrection
Undercorrection means that the eye remains shortsighted after the eye has stabilised. Should the degree of residual myopia be of sufficient concern to the patients, the eye can usually be retreated at a later date.
- Regression
This is a gradual returning of some of the refractive error.
- Decentration
Decentration of the zone of treatment is rare. Measures are undertaken to reduce the likelihood of this occurring.
Decentred treatments may cause permanent loss of sharpness and this may be difficult or impossible to reverse with current technology. If severe, contact lens wear may be needed to improve vision.
- Post Operative Pain
There is usually little or no pain with Lasik unless there is disruption to the surface cell of the cornea. PRK is more uncomfortable during the healing phase than Lasik.
The use of a contactblens as bandage , and pain killers help to reduce discomfort.
- Delayed Epithelial Healing
If PRK is performed the surface epithelium is removed just prior to the laser surgery. It usually heals in 2 to 4 days but rarely there may be a delay in this process.
- Corneal Haze and Scarring
This is usually only present in PRK patients. This occurs as part of the healing process after corneal remodelling and is usually at its maximum severity 6 weeks after the laser treatment. This gradually settles by 3 to 6 months. Steroid drops may be used to control the degree of haze. The haze is seen by the ophthalmologist with a microscope but is usually not detectable by the patient. If severe, it can permanently reduce the sharpness of vision.
In Lasik a faint scar at the edge of the flap away from the line of vision is can be seen after surgery when the eye is examined under the microscope. Central scarring is very rare after Lasik.
- Halo Effect
This is an optical effect that is noticed usually in dim light as the pupil enlarges; as the pupil dilates the untreated peripheral cornea produces a second faded image. It is less frequent with larger treatment zones being used today and is less noticeable when the second eye is treated.
- Light Sensitivity or Glare
This is not usually a significant problem however sunglasses are recommended. During the first few months there may rarely be some discomfort driving at night or in bright sunlight.
- Dry eyes
A small proportion of patients experience a gritty feeling in the eyes after surgery. This can usually be controlled with lubricating drops, and usually settles over a period of weeks to months.
- Flap complications
If the flap is not cut correctly, becomes folded or displaced the visual result can be imperfect. Germs, cells or other material can occasionally cause problems under the flap. Serious flap related problems are rare, and can usually be dealt with if they arise to improve and stabilise the situation. Unfortunately in very rare instances, flap complications can result in permanent reduction in vision, glare problems or ocular discomfort.
- Other Complications
There are some additional complications which may be serious, for example, corneal infection, persistent corneal swelling, corneal perforation and cataract. Fortunately these are extremely rare.
Why does Dr Cherny wear glasses?
One of the questions that Dr Cherny is most frequently asked is “why haven’t you had laser to your eyes? ” Simply explained, Dr Cherny is a happy glasses wearer. He has very dry and allergic eyes and is one of the main factors that make him an extremely poor candidate for this therapy. He is always happy to point out that if by wearing glasses himself he makes people ask “Gee, I need to think carefully about this, before having treatment”, then that is quite correct. Elective surgery on your eyes is a serious decision, and not everyone is suitable.
Many eye surgeons and optometrists, both in Australia and overseas, with different lifestyles and otherwise healthy eyes have chosen to have laser eye surgery for themselves, and for their children.
Dr Cherny and his staff pride themselves on educating their patients thoroughly, so that they can make educated decisions as to how to care for their eyes, and choose wisely when considering laser sight correction. You are welcome to book an appointment at our laser eye surgery clinics in Melbourne, to speak with us.