Here in Miami and probably elsewhere, about half of my patients having cataract surgery also have dry eyes or eye allergies or various types of inflammation of the eyelids. It is amazing to me how this problem can reduce the good results of well done cataract surgery (LASIK surgery as well). In many cases the condition is only slightly bothersome prior to surgery, however, when you have cataract surgery with one of these ocular surface diseases present, there appears to be a surprising diminusion of the visual outcome. If you have chosen to make a significant “lifestyle enhancement” with a multifocal lens insertion at the time of cataract surgery you want to maximize the result and achieve the ultimate potential of this new technology.
During the preoperative examination at Miami Eye Center, we look at the tear film using new technology and are able to determine if you have a deficiency in the water component of the tear film or if your tears are evaporating too fast. When found, patients are treated with artificial tears preoperatively and the surgery itself is performed in a way which protects the surface of the cornea. If we find an inflammatory problem causing a tear film deficiency we treat that with a course of cortisone eye drops before the surgery. We might also use Restasis to decrease inflammation. In cases of eyelid inflammation a round of oral antibiotics as well as antibiotic eyedrops over a period of several weeks can improve the tear film.
The take home message here is that there are subtle issues which can impact the outcome of your eye surgery that are beyond just having a good procedure and your surgeon needs to evaluate these factors and discuss them with you.
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.
Patients of all ages ask me what they must do to be free of eyeglasses. The answer lies in their age and their vision requirements.
The first group of folks are the younger aged. These are people who are nearsighted or farsighted with or without astigmatism and who when they have their contacts or glasses on, can read without the need for additional reading glasses. This group is “pre-presbyopic.” The approach to getting this group out of glasses or contacts is straight forward. We must correct the refractive error (nearsightedness, farsightedness or astigmatism) and they are set. In most cases this is done with LASIK or PRK in individuals who have a refractive error which has stopped changing with age and meet the other criteria for safe refractive surgery.
Eliminating the need for glasses gets a little more involved in the next group; the presbyopic group. These people need reading glasses in addition to their contacts or distance glasses correction; this is the group that wears bifocals. There are several theories as to the mechanism of this progressive need for reading glasses but the bottom line is that the lens of the eye losses its ability to focus at near. This inability is superimposed upon ones nearsighted or farsighted condition. This gets confusing because a 48 year old nearsighted individual can see well at near without glasses but once the glasses go on they no longer can see close. A younger nearsighted person will see well at near with the distance correction. So what must we do to eliminate glasses? In my surgical ophthalmology practice there are two ways to do this. The first is to do LASIK or PRK with the dominant eye corrected for distance and the non-dominant eye for near (monofocal). While this may sound “wild and crazy,” about 20%-30% of the population is capable of doing this. When patients inquire about this approach, we fit them with trial contact lenses for the day which simulates the monofocal condition. In general, people who are not suited for the monofocal correction know immediately after putting the lenses on. For those who are comfortable we go to LASIK or PRK and permanently correct the refractive error.
The other 80% used to have no option but to wear bifocals. Now there is an excellent second option; multifocal lenses. These are acrylic lenses which can be permanently placed inside the eye which give good distance and near vision in each eye. The lenses create two images at the retina, one for near and one for far. Depending upon which image your brain wants to see will determine which image it recognizes. This works similarly to being in a room where there are several conversations going on simultaneously. Your brain will direct your attention to one of these conversations and you will hear it at the exclusion of the others and in an instant you can switch to another conversation and not hear the first.
In multifocal lens surgery your clear lens is surgically removed and replaced with an acrylic lens which has been calculated to neutralize your refractive error and at the same time correct for near vision. I prefer the Restor Lens manufactured by Alcon Labs. The surgery takes about 15 minutes and one eye is operated at a time. The second eye is operated about 2 weeks later. There is very little down time as people feel good the next day.
This surgery is available for those of any age as long as they are presbyopic. In younger presbyopes we remove the clear lens and instill the multifocal lens. In those older presbyopes requiring cataract surgery, the same lens is placed with the same benefits.
I or one of the surgery counselors will be pleased to discuss these options with you. Give a call.
It is my pleasure to open the BLOG section of this website. I hope to give the reader an opportunity to obtain up to the minute information about the newest technologies offered at MIAMI EYE CENTER as well as the greater ophthalmic community. I encourage those with an interest to become involved with questions or comments.
This evening, I was reviewing the chart of patient C.B. who is a very young 72 years. He had R.K. (radial keratotomy) surgery in Columbia 15 years ago. He was quite pleased with the outcom of that surgery until recently when became bothered by nighttime glare while driving. He consulted an optometrist who diagnosed cataracts and referred him to this office.
I began performing radial keratotomy surgery for myopia in 1982, PRK in 1996 and LASIK in 2000. Now that many of my patients from those days have “grown up” they are developing cataracts. Cataract surgery in folks who have had prior RK, PRK or LASIK presents a unique challenge to ophthalmic surgeons but one which I have managed incorporating the newest technology. The challenge facing the surgeon is in selecting the proper intraocular lens to place in the eye at the time of surgery. For patients who have not had prior refractive procedures, the selection process is routine. However, the standard computer programs used for the average patient do not work for people who have had prior RK, PRK or LASIK. If the incorrect lens is utilized, the patient will be nearsighted or farsighted following the surgery.
In the clinic today, I measured the power of C.B’s eye as one would for making eyeglasses. I then inserted a special diagnostic contact lens and repeated the process. This yielded the true power of the cornea and that data was used in two additional programs to yield the power of the intraocular lens to be inserted at surgery. These mathematical manipulations have been evolving over the past several years and I have found them to be quite accurate.
The goal of modern cataract surgery is not only to achieve excellent vision for the patient but excellent vision without glasses. This goal can be achieved for many patients even in complex cases as outlined here.
