Medical information gathered by Dr. Marco Abbondanza on experience with ocular surgery
Eyeglasses
Eyeglasses are a valid solution when the impairment is not high. With medium or high impairments, the lenses are heavy and unattractive and often produce distorted images, making them an unsatisfactory solution.
Contact lenses
Practically all problems having to do with eyeglasses are overcome through use of contact lenses.
They've represented a giant step forward in correcting optical problems in visual impairments, especially in astigmatism or medium to high levels of myopia.
Not everyone tolerates them especially if worn all day. Many people become intolerant to contact lenses even after years and must quit using them.
Contact lenses also require great care to avoid risks of corneal infection which can weaken vision.
Surgical Techniques
A careful surgeon, attentive of his patient's well-being, must be well informed of the many different surgical techniques.
In other words, the surgeon must update his know-how of the impairment he is about to correct instead of trying to adapt the patient to the few techniques that he knows.
Myopia was the first visual impairment to be surgically corrected.
If the impairment is light or medium-high (-1 dioptre until -10-12 dioptres), it can be corrected through an operation as an outpatient or with a technique that touches the external part of the eye.
Problems at a more elevated stage can be dealt with in an outpatient operation but must be corrected internally. External techniques are: radial keratotomy and two main excimer laser applications: PRK and LASIK. Internal methods are artificial crystal implantation and parallel crystal implantation.
Both myopic and hyperopic astigmatisms can be corrected with the same methods used for myopia and hyperopia.
Radial Keratotomy
During the second world war, Dr. Sato, a Japanese physician, invented radial keratotomy as a way of correcting myopia.
But the methodology was not fully developed since technology of those days wouldn't allow it. In 1972, professor Fyodorov developed a modern and simple operating program for other surgeons to copy. Hundreds of thousands of persons all over the world have since undergone operations using that technique.
Radial Keratotomy is a technique having a margin of safety worthy of comparison to more recent techniques seeing the great number of persons treated.
This technique appeared destined to be surmounted by the arrival of excimer laser technology, but instead as years pass, it continues to be backed up by the most important American surgeons as well as by Dr. Abbondanza who had begun using laser.
The main problem with this technique is that it must be performed by a surgeon who is familiar with it and has used this method for many years.
Radial keratotomy can be used to correct myopia that is in the range of -1 - -5 diopters.
Dr. George Waring, one of the best American refractive surgeons, considers radial keratotomy to be a modern, efficient and safe technique in the treatment of light cases of myopia.
Since 1987 Dr. Abbondanza has been using radial keratotomy. He specialized in this technique at Professor Fyodorov's institute in the Soviet Union.
Excimer laser
The excimer laser is a piece of equipment whose ultraviolet radiation is capable of eliminating several thousandths of millimeters (micron) from the corneal surface.
A computer controls the laser making it almost precise.
There are different ways of using laser depending on what impairment needs to be corrected.
Laser can be used on the corneal surface PRK or in the thickness of the cornea, LASIK.
The third and most recent way of using laser surgery is called Lasek.
PRK (excimer laser on corneal surface)
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PRK or Photo Refractive Keratectomy or corneal photo-ablation can precisely treat even serious impairments such as myopia, astigmatism and hyperopia
PRK advantages excimer laser on corneal surface)
There are three main advantages:
1) simplicity for both surgeon and patient
2) precision
3) lack of risks
"What happens when I decide to undergo an operation with PRK?"
(Excimer laser on corneal surface)
The patient lies under a microscope while an anesthetic and antibiotic eye medication are applied.
After about 10 seconds when the anesthetic takes effect, the corneal layer on the surface (epithelium) is removed and the patient is told to stare at a red light positioned above his eyes. The laser treatment will then begin and will last up to 90 seconds.
More eye drops will then be used as well as a protective contact lens which will have to stay in place for a few days.
The laser treatment is then over and the patient can go home.
He may experience sensitivity to light and may feel some pain.
The contact lens and the pain killing medication will help the patient lead an almost normal life.
His lifestyle will be fairly normal after 4-5 days and will be perfectly back to normal after one week.Excimer laser machinery is extremely expensive and must be regularly and carefully serviced bringing on more costs. Therefore it is not an affordable technique for all surgeons or for all patients.
PRK laser treatment is used worldwide to correct myopic, astigmatic and hyperopic visual impairments.
LASIK
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Lasik or Laser and Excimer Assisted Kerato- mileusis treatment can substitute surface treatment when the level of myopia is not very high.
The operation is divided into two parts:
1) an instrument called microkeratom is used to make a superficial flap of the cornea. The flap, an extremely thin layer of the cornea, is moved and lifted leaving the internal part of the cornea uncovered.
2) laser treatment is used on the uncovered cornea as though it was PRK, then the flap is replaced on the rest of the cornea.
LASIK advantages (intra-stromal excimer laser)
An eye-drop anesthetic is used for this non-painful treatment.
The patient feels nothing except the presence of a foreign object.
Results are immediate although total vision returns after a few days.
LASIK is used all over the world to correct myopia, astigmatism and hyperopia
PRK (surface laser) and LASIK (intrastromal laser) complications
Both PRK and LASIK laser treatments are done through computer use and are precise within a thousandth of a millimeter. After any surgical intervention, our body immediately begins a series of mechanisms which help it to heal.
All treatments are calculated so that the original impairment is completely corrected by the end of the healing process.In order to calculate the final result, statistics are used based on figures from the thousands of patients treated making things extremely accurate. However, there is still the risk that since patients heal differently, the results may be slightly different. This risk increases as the original impairment grows.
The result will nonetheless be very satisfactory although in some cases glasses with light lenses might be needed. Where some visual impairments still exist, it's possible to operate again to complete the correction.
When this occurs, the regression can be associated to problems related to the healing process of the individual and are not caused by a surgeon's ability.
A light veiling of the treated cornea due to the regression may set in, causing a light decrease in vision and some problems with nocturnal vision. This veil, called haze, normally regresses on its own after a few months.
Haziness appears only after use of PRK and is not possible with LASIK.
The above problems are fairly common when using first and second generation laser equipment, but are very rare with the new third generation equipment.
