WebMD Live Events Transcript
Cataracts are one of the leading causes of vision loss in the United States. As part of Cataract Awareness Month, ophthalmologist Guy Knolle, MD, joined us to answer your questions about cataracts -- symptoms, prevention, and the latest treatments -- on Aug. 3, 2004.
The opinions expressed herein are the guests' alone and have not been reviewed by a WebMD physician. If you have questions about your health, you should consult your personal physician. This event is meant for informational purposes only.
Welcome to WebMD Live, Dr. Knolle. It's cataract awareness month. What are the most important things you want us to be aware of about cataracts?
I think the most important thing is number one, it's a clouding of the lens inside the eye and is not significant until it interferes with vision. They can be treated successfully in at last 98 times out of 100. I tell my patients that when they close one eye if they can't see to do all of the things visually that they want to do out of the other eye with their best corrective lenses, that they need to consider having cataract surgery to correct this loss of vision.
Of course, the first thing that has to be determined is whether or not there are any other causes for their reduced vision. If a diagnosis of significant cataract is established by examination, this can be treated surgically and often, even if they have a small amount of macular degeneration, removal of significantly dense cataracts can result in improved vision.
What is the first symptom of cataracts?
The first symptom of a cataract can be glare, especially when looking into lights at night; and this can be associated with haze, which prevents clear visualization of the roadbed and highway markings. But to an astute observer, it's simply the loss of clarity of vision, loss of sharp images. The problem is that frequently cataracts develop very slowly, and minimal changes that become maximal changes are often overlooked or not noticed.
It's hard to remember sometimes what good vision is like compared with the gradual loss of definition that occurs with a cataract. This is especially true when the cataracts develop at about the same rate in each eye, so that there's no good standard of comparison.
We do have a way to roughly evaluate glare with an examination called the brightness acuity test, abbreviated BAT. This can give the examining surgeon a good idea of the patient's ability to see in bright daylight and when looking into oncoming headlights at night.
The examining doctor can help the patient evaluate their gradually deteriorating vision when this is occurring, and more objectively than the patients can sometimes evaluate their own vision. The average age for cataract surgery is approximately 73 to 75 years old. But cataracts can occur in the 30s, 40s, and 50s. Of course the older the patient gets the more common the cataracts. But again, the presence of a cataract is not significant in itself. The associated loss of vision, if present, is significant.
Given your description of the development of cataracts, how often should we be getting eye exams?
Thinking of the people that are in the cataract age group, age 60 and over, I would think it would be prudent to be examined yearly to be certain that corrective lenses were up to date and as fully corrective as they can be made.
I was told by my ophthalmologist recently I had the starting of a cataract in one eye. How long should I wait to have surgery on it? Should I wait until the other eye starts getting one to have anything done?
When a patient develops a cataract in one eye that is causing a loss of vision to less than useful levels, it's time to have the cataracts removed and replaced with an intraocular lens. The best guideline is to keep in mind that we want to keep both eyes in as good a repair as we possibly can. Once a significant cataract develops that reduces the vision in one eye, we know two things for sure: one is that the patient is out of spares, and number two, their ability to judge distance is deteriorating.
Many years ago, patients were told that the cataract should not be removed until it was "ripe." This was because prior to the 1970s, the entire crystalline lens was usually removed and it was easier to remove the lens if its attachment's zonules were weak. The analogy was that it's easier to pull a pear off a tree if it's ripe than if it's green. If it's green you could pull the tree down trying to pull the pear off. When the entire lens was removed through a large 180-degree incision, the surgeons preferred that the lens could be easily removed so that the fluid behind the lens would not be disturbed.
Beginning in the 1970s, small-incision cataract surgery became gradually more and more popular as a result of the late Dr. Charles Kelman from New York City. Currently, almost every good cataract surgeon in the world uses this small-incision technique called phacoemulcification. During this operation, parts of the lens are selectively removed and a part of the lens is left behind to support an intraocular lens. A 3-millimeter or less incision is required. The anterior capsule of the lens is opened and removed through the dilated pupil and ultrasound, in association with irrigation of balanced salt solution and aspiration, is used to soften and emulsify the lens material so that it can be aspirated through this small incision.
We now use foldable injectable intraocular lenses that can then be delivered into the remaining lens capsule supported by the zonules. The injected, foldable intraocular lens spontaneously unfolds and the incision can be closed by injecting balanced salt solution into the margins of the incision without the use of sutures that can create unwanted astigmatisms. If corneal astigmatism is present, it can be treated with relaxing corneal incisions in the periphery of the cornea at the same time cataract surgery is performed.
Does the cataract surgery also fix other vision problems such as farsightedness or near sightedness? Will I be able to get rid of my glasses after cataract surgery?
The intraocular lens replacement can consist of a monofocal lens, like we've used since the 1970s and before, or it can consist of a multifocal intraocular lens that has been used in recent years. If a monofocal lens is used, the lens can be adjusted to be in focus in the distance, at near, or somewhere in between, but there is a single focal point. It is monofocal, and areas that are not in the focal plane will not be clearly seen.
If a multifocal intraocular lens is selected, the power is calculated appropriately, and the lens resides within the capsular framework as calculated, the patient's vision should be good in the far distance, at intermediate distance, and at near. In other words, the vision should be good throughout the range of vision at all distances.
The Array intraocular lens, manufactured by Advanced Medical Optics, was approved for cataract patients over the age of 60 in September of 1997. I personally have a great deal of experience with this lens, and have used it in essentially all of my cataract patients since the year 2000.
In fact, I had such good experience with my patients that after I had used the lens for two years, I made plans to have the lens implanted in both of my eyes. This was done last year and I've been very happy with my vision and with the fact I no longer have to wear trifocals. I did not have cataracts and my vision was corrected with my spectacles to 20/15 with no glare disability, and now I can see 20/20 with no glare disability without glasses.
In my experience, more and more patients are looking to clear-lens exchange as a refractive surgical correction, because it can provide good vision using both eyes together as compared with monovision at all distances.
There are other accommodative or multifocal lenses now coming available, and over time we may see that they offer advantages that are better than the Array. But in my opinion, this remains to be seen. The only significant criticism that I'm aware of with the Array lens is that since it has concentric circles of varying power, to provide clear vision at all distances, or through a wide range of distances these circles in the lens put circles around lights at night. They don't cause glare, they only put a circle around the light that makes it appear larger in diameter than it would without the circle. There is no interference with visualization of the roadbeds or road markings.
I had a patient that was a truck driver. He drove an 18-wheeler day and night in all kinds of weather and he developed cataracts at an early age, in his 50s. The first time I did surgery on him before I was using the multifocal implant and I implanted a monofocal lens that was calculated to correct his distance vision. He felt like he could see so well that he delayed surgery in the second eye for two or three years.
When he came back for the second surgery, I explained to him that I had now the use of a multifocal implant and there was some question in some surgeons' minds about whether or not the two would work well together. But I told him that from my previous experience with a multifocal lens in 1989 (that had never been approved by the FDA and "went away"), I felt the multifocal lens would fill in the gaps and work well with his monofocal lens in the first eye. It made sense to the patient, and he elected to have the multifocal lens implanted in his eye.
About two months after his surgery the patient was so delighted in his depth of field and his ability to see so many distances with his two eyes working together that he went to the drugstore and bought a thank you card to send to me. That confirmed what I had thought about the lens filling in the gaps that a monofocal lens leaves, and the usefulness of this multifocal lens day and night on the highway.
Why is the lens approved just in patients over 60? What about those who have cataracts and are not yet 60?
The lens is used as an off-label device in people other than those that are over 60 years of age. When we use the Array lens in cataract patients or to do clear lensectomies in patients without cataracts, these are all off-label uses as LASIK surgery once was. It's done at the discretion of the surgeon and the patient.
I have mild cataracts. My eyes HURT in bright light and most outside light unless it is raining. This light doesn't seem to bother the people around me. At night oncoming headlights cause the same pain. Is it normal to have PAIN with cataracts? Also, I have been told that sunglasses don't help because the pupils enlarge allowing more light to enter (I wear them anyway).
Pain is not normal with cataracts. Some people are more sensitive to glare than others. When we say pain, there's a broad spectrum between pain, discomfort, and annoyance. Pain, per se, is never the result of a cataract. I think you need to be sure you have pain, because it can be very annoying to have glare. There's a big difference between pain and discomfort.
Do all cataracts grow at the same rate?
No, all cataracts do not grow at the same rate, and it's impossible to predict the progression of the lens' opacity. It can vary vastly from one eye to the other, even in the same head, and when patients ask me, "How long will it be before I need cataract surgery once the diagnosis is made?" I quickly look at my watch, and they get it. You can't predict when. It's like telling someone how long they're going to live. When patients get really concerned about the fact they may have to have cataract surgery in the future, I tell them I just hope they live long enough to need it, because it's very relative.
Is cataract surgery painful?
Cataract surgery is normally not painful, takes less than 20 minutes to do, and results in good vision. If I had not had the confidence in the technology and the procedure, I would not have had surgery just to avoid the use of spectacles. The operation doesn't just work most of the time, it works almost every time. But we're not living in a perfect world, so it cannot work every single time, and each patient has to take some risk for gain.
Is there a greater chance of cataracts in a person who has diabetes than with everyone in general?
Probably. That's the simple answer, but I don't know of any huge study that's been done.
My husband had one attempted cataract procedure that could not be completed because his pupil would not dilate enough (he had a stroke that affected the occipital lobe of the brain and he has limited vision) now the doc wants us to go to another facility with more modern technology. My question: Are the risks higher for this than normal cataract surgery?
The risk is slightly higher, but I think your doctor is giving you a very good recommendation. There are some centers that can deal with these problems better than others. It's important to seek out these locations for treatment once you realize you have a special problem.
Can anything be done to prevent cataracts or are they an inevitable part of getting old?
I tell patients when they ask me what causes cataracts that they're the result of three things: age, hereditary, and bad luck. Almost everyone develops some loss of clarity of the lens as they age, and the metabolic changes of the lens epithelial cells that undergo these opacities are being studied. The visual needs of the patient really dictate when they will require surgery for cataracts
Dr. Knolle, before we wrap things up, do you have any final words for us?
Another consideration, with respect to clear lensectomy, or lens exchange in the patient without cataracts, is the cornea normally doesn't change as we age, and the axial length of the eye doesn't change unless surgery or injury changes it. So if we replace the lens with a fixed known entity that won't change, the visual acuity should remain basically the same throughout life, because the light that's focused on the retina is the direct result of the corneal curvature, the axial length of the eye, and the power of the lens.
When patients undergo LASIK, the refractive power of the eye is adjusted by changing the shape of the cornea, and this can remain stable for an indefinite period of time, but the lens continues to change as we age, which can again change the refractive power of the eye.
I appreciate the opportunity to answer questions, and I hope I have helped you to understand cataracts and refractive surgery, especially with respect to refractive surgery, because patients that are presbiopic that require reading glasses have a way now to surgically correct this normal aging deficiency in their vision, and at the same time we can correct farsightedness, nearsightedness, and astigmatism.
Our thanks to Guy Knolle, MD, for sharing his expertise with us.
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