Many of my Miami patients who return sometime following their LASIK/PRK will enthusiastically relate their life experience as it pertains to their surgery. Here I want to tell my story which basically charts the entire history of LASIK as I was there at the beginning and have grown with the advancements and re-directions.
In 1986, I was introduced to the excimer laser which had been developed at IBM in New York. It was a precision cutting device which was only used to demonstrate how you could cut a square in a strand of human hair; a party trick. Eventually some researcers at Columbia University came up with the idea of aiming the laser at the cornea with the hope of reshaping it and eliminating nearsightedness. The device which had been developed in New York could not be used in the USA thanks to the FDA so I traveled to London and on to Berlin where the procedures were being done. The trips were fun and the technology was spectacular.
My first opportunity to actually use the laser was in 1996, when it finally received FDA approval. Tne LASIK procedure at that time was not in existance. We were aiming the laser at the surface of the cornea without creating a flap; this was PRK, Photorefractive Keratoplasty. We could only treat myopia as there was no algorithm for farsightedness or astigmatism. The procedure worked very nicely for the limited number of patients that were treatable. The down side was that it was a painful postoperative coarse. Because of the pain created by lasering the front of the cornea, the notion of cutting a flap and lasering the interior gained popularity. There turned out to be much less pain with this approach and so began LASIK.
The process of cutting an extremely thin section of cornea became the challenge. One of the earliest and most popular devices was actually developed in Hialeah. These cutting devices are called keratomes. In the early days of LASIK the application and successful use of the various keratomes was a tricky undertaking as the equipment was unforgiving if the operator made the slightest error. There were dislocated flaps, irregular cuts and partial cuts. But since the vast majority of folks did very well without pain we forged on. Ultimately, the keratomes became automated and complications became rare. Surgeons still had in the back of their minds the ultimate safety of the PRK as there is no flap and therefore no flap related problems. At the same time there emerged a class of eye drops known as NSAIDS (non-steroidal anti-inflammatory drugs). These drugs eliminated the postoperative pain following the PRK. Thus began the swing back to the old days of PRK. Ofcoarse by now we were treating myopia, hyperopia and astigmatism.
While I watched the excimer laser go through four generational changes, the newest kid on the block is the femtosecond laser. This laser is used to cut a precise flap with minimal complications.
All of this brings us to the present. In my consultations with refractive surgery candidates we discuss these options. Many people want to reduce the risk factor to as close to zero as is possible and elect PRK. Some need to have an immediate visual result and short term recovery period and elect LASIK (the return of vision following PRK can be five to six days). Others have thin corneas wherein PRK is the only option. So it all comes down to fitting the procedure to the patient and not visa versa. In the end, personalized care and attention to detail leads to a happy patient and a happy doc and we all sleep well at night.
“I had cataract surgery 6 months ago but I’m still having blurry vision.” I see patients here at Miami Eye Center who come to see me for a second opinion totally distraught over the issue and in many instances their degree of concern is unwarranted. This could be you, if so there are several things to consider. Firstly, what is the cause of the blurriness and secondly, can it be fixed?”
We can start analyzing the problem from the front of the eye (cornea) and working to the back (retina). Some of the issues are simple yet overlooked while others are complex. If you have had a multifocal lens implant there is no margin of error as these lenses are unforgiving. If your tear film is not good you could be losing vision. I have many patients complain of poor acuity only to find that by putting a drop of artificial tears on their eye they recover substantial vision. A long term program of tear film enhancement leads to continued excellent vision.
There could be residual nearsightedness, farsightedness and or astigmatism. If this is the case and you have had a multifocal lens implant it is incumbent upon the surgeon to correct this. If you have opted for a generic lens implant, eyeglasses is the answer. However, with multifocals you should be offered LASIK correction which has the potential to completely correct the blurry vision.
The intraocular lens is placed into the eye on a clear membrane (like Saran wrap) called the posterior capsule. On occassion this clear membrane becomes cloudy and impacts the vision potential. This is easily treated with a Nd:YAG laser procedure which vaporizes the membrane and thus clears the vision.
Moving to the back of the eye there is the retina. If there is a problem with the retina it is the same as taking a photograph with bad film in the camera. In a small percentage of surgeries there could be swelling of the retina known as cystoid macular edema. This has a profound effect in reducing the vision. Fortunately, it is self limited to several weeks to months and often responds to therapeutic eye drops.
While the point of this discussion is to inform the reader that all is not lost if at first glance the outcome of cataract surgery appears to be less than optimum, however, there are a number of complications which require extensive evaluation and complex repair. One must keep in mind that if you lump all of the possible complications of cataract surgery into one, the risk is about 3%, one of the safest major surgical procedures performed today.
Here at Miami Eye Center I am seeing a gradual trickle of RK alumni who had their surgery in the 80’s now coming back for cataract surgery. While the outcome from cataract surgery following prior RK can be excellent, there are a number of important issues that should be understood by the patient. The cornea is a very complex tissue that is perfectly designed to help focus light on the retina and the result of making radial incisions vastly alters the optical properties. Most importantly is that the cornea loses its stability. As the years have past since the RK, the cornea has flattened. In addition, within any given day the cornea shape changes from flat in the morning to steep in the evening. This often makes people farsighted in the morning and nearsighted later in the day. When we make the preoperative calculations for the intraocular lens we are in effect shooting at a moving target. When the calculation is off, the patient will be either nearsighted or farsighted following the surgery. In addition, the algorithms applied to normal corneas are impacted by the flatness of the RK cornea further making the calculations difficult. While I have a pathway of making the appropriate calculation adjustments I still warn patients about the above possibilities. Also that one can not be certain of the outcome until several months following the surgery as the cornea continues to flatten. If the power of the eye is not satisfactory there are several options for improving the outcome. Eyeglasses are easiest but perhaps not the first choice. Contact lenses might be worn. Lastly, it is possible to insert a second intraocular lens into the eye to add or subtract the power necessary to yield good vision without glasses. I have done this on a number of occasions at which time the calculation of the “piggyback lens” is straight forward. I would recommend against a multifocal lens implantation because the multifocals don’t perform well if there is any significant power error. A second reason is that there could be too much glare as a result of the optical properties of the RK cornea combining with the optics of the multifocal lens. In many instances the Toric Lens has been helpful in managing astigmatism that is often seen after RK surgery. It is important that the surgeon understand the type of astigmatism since the lens is not optimally effect in irregular astigmatism. My advice to any post-RK cataract surgery candidate is to be certain that their visual loss is due to cataract and not a cornea related issue and find a surgeon who has been there, done it and has a T-shirt.
Most of my patients think that astigmatism is a disease; it is not and it’s time to clear the air. Astigmatism is a normal condition effecting 80 percent of the population. Astigmatism is caused by an irregular shape of the cornea; the clear window on the front of the eye is the cornea. In a non-astigmatic eye it has a round curve in all directions, like a basketball. In the case of astigmatism, it is shaped like a spoon. In one direction there is a steep curve and in the other there is a gentle curve. This is called “regular astigmatism.” When light passes into the eye it must pass through the cornea. When there is no astigmatism the light comes to a perfect focus on the retina and the vision is excellent. When light passes through an astigmatic cornea light from different directions is focused differently and there is a blurry image projected onto the retina.
Regular astigmatism is easily corrected with eyeglasses or contact lenses. If you hold your glasses out in front of you and look at a picture on the wall while rotating the glasses you might see some changing distortion; this is the lens correcting your astigmatism. Rigid gas permeable (hard) contacts are excellent at correcting astigmatism while soft lenses are less effective.
There are excellent surgical techniques for the correction of astigmatism. The oldest method that I began using in 1982 is astigmatic keratotomy. Here small straight incisions are made on the cornea across the steeper curve (meridian). This tends to flatten that meridian and steepen the flatter meridian, ultimately making the cornea more spherical. Along came LASIK where after several years there emerged an algorithm for the correction of astigmatism along with nearsightedness and eventually along with farsightedness. Very substantial amounts of astigmatism can be corrected with LASIK. More recently, we have added a variation of astigmatic keratotomy (AK), known as limbal relaxing incision (LRI). Here the corneal incision is moved to the outer edge of the cornea and is curved rather than straight. It is more predictable than AK.
When patients come for cataract surgery we always evaluate their astigmatism. This is done so that we can calculate the power of the lens to be implanted at surgery and also to be in the position to offer them an opportunity to have the astigmatism corrected with LRI at the same time. The purpose is to enable patients to achieve excellent vision without glasses when the cataract surgery is done. We usually reserve the LRI for small amounts of astigmatism because there now is available the toric lens. This is an intraocular lens with optics designed to neutralize the astigmatism along with the correction of myopia or hyperopia. This lens is implanted just as any lens might be then it is rotated into a position to match the steep meridian on the cornea, thus neutralizing the astigmatism.
So don’t be concerned when you learn that you have astigmatism; it could be a lot worse.
Now that you have a visually significant cataract, that is, a cataract that is interfering with activities that you enjoy doing or those that you must do, the choice is no longer “should you do the surgery,” rather “how should the surgery be done.” Needless to say, this decision must be made during a consultation with an ophthalmologist with whom you feel comfortable. Keep in mind that this is the last and best opportunity to not only remove your cataract but to correct other problems such as nearsightedness, farsightedness presbyopia and astigmatism.
To help with the discussion, the lens options fall into several classes; MONOFOCAL LENSES will deliver good vision at a single point in space, ie, distance or near. A modern variation on this lens is the ASPHERIC LENS which has a curvature which neutralizes the curvature of the cornea and thus reduces glare and other types of distortion. A TORIC LENS will correct astigmatism at the same time that it corrects nearsightedness or farsightedness and it has recently been manufactured in an aspheric form. Then there are the MULTIFOCAL LENSES which are in many instances, aspheric as well. These lenses correct for distance and near vision. There is the Restor lens from Alcon Labs, the ReZoom lens and more recently the Tecnis lens from AMO. In addition, the Crystalens from Bausch and Lomb which is somewhat different from the other lenses but ultimately yields a similar outcome.
The issue is that there are numerous lenses to place in the eye at the time of surgery. The lens must be matched to the patient’s visual needs, not the other way around; one lens does not fit all. On the one hand, an 80 year old with macular degeneration and cataracts who does not mind wearing reading glasses would fair best with a lens that provides only distance vision and perhaps it should be an ASPHERIC LENS which minimizes glare and maximizes distant vision. The opposite situation might occur in a 50 year old who needs distance vision, computer vision and reading vision and would be willing to wear reading glasses occassionally. The latter case would call for a MULTIFOCAL LENS of which there are several.
It must be said that every style of lens has different advantages and disadvantages and these must be reconciled with the patient; that is my job. I must find out what you expect and want from the procedure. What are the tasks that you want to do without glasses and which are you willing to occassionally put the glasses on in order to perform.
Remember that cataracts come with having birthdays and perhaps this year’s present might be good vision and possibly no glasses to achieve that end.
