IOLs, two opinions, two recommendations, more confused

If you are thinking about having Lasik, IntraLasik, PRK, LASEK, Epi-Lasik, RLE, or P-IOL eye surgery, this is the forum to research your concerns or ask your questions.

IOLs, two opinions, two recommendations, more confused

Postby alake » Fri Nov 27, 2009 5:19 pm

I recently had consultations with 2 reputable refractive surgeons in the Minneapolis/St. Paul area. The first exam seemed less thorough than the second. I'm near 50, have a high prescription and am not a candidate for lasik. The first surgeon said lens replacement (ie. cataracts surgery without cataracts) was the better option but that I could get the Visian lens. The second surgeon did not recommend the Visian and thought only the lens replacement should be done. He also recommended a consult with a retina specialist just to be sure there are no out of the ordinary risks. I really didn't consider that lens replacement would be the only option and I am not keen on it at all. I think I need a 3rd opinion. I'm not going to keep shopping around but it seems like 2 out of 3 might sway me. If it looks like lens replacement is the only option, I probably won't do it. That's just too drastic because it's not reversible. Any recommendations for another surgeon who does implants in the Twin Cities area? I don't want to name the clinics I went to so more than 2 recommendations would be good. Also are there any new products on the horizon that might work better as an implant where the space to put it isn't huge? Thanks.
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Re: IOLs, two opinions, two recommendations, more confused

Postby LasikExpert » Mon Nov 30, 2009 8:58 am

The Visian phakic intraoculer lens (P-IOL) is implanted immediately behind the iris and in front of the natural crystalline lens of the eye. Refractive Lens Exchange (RLE) is exactly the same as cataract surgery but for the purpose of reducing a need for corrective lenses, rather than to remove a cataractous (cloudy) crystalline lens.

In my opinion a P-IOL is utter foolishness unless there is something that I'm missing from the information you have supplied.

Let's start with the fact that a P-IOL is a temporary lens. Unless you meet an untimely end, all P-IOL lenses must be removed. They may be okay from 5-15 years and sometimes longer, but either the P-IOL will need to be removed when you eventually develop cataracts or when the cells on the inside of your cornea (endothelium) have reduced in number to the point the Visian must be removed to maintain the safety of your corneas. If you elect for the P-IOL, you are electing at least two separate surgeries. One in, and one out, plus cataract surgery later in life.

The amount of room between the iris and the lens is minuscule. The rate of induced cataracts from trauma to the crystalline lens in the first 50 P-IOLs your surgeon perfoms will be high, even if s/he is an excellent surgeon. This is an important issue because If the Visian P-IOL disrupts the natural lens in the least amount either during surgery or after recovery, you are very likely to develop a trauma-induced cataract. If a cataract is induced, then the P-IOL must be removed and you will need cataract surgery, which is replacing the crystalline lens with an artificial intraocular lens (IOL).

You state that you have a high correction and the doctor recommended you have a retina exam to verify the health of your retina. This, and the fact that the Visian only corrects myopia (nearsighted, shortsighted) vision, indicates that you are highly myopic. A Visian P-IOL to correct high myopia is relatively thick, reducing even more the amount of room to maneuver the P-IOL into place. Additionally, a high myope will want to introduce as little trauma to the eye as possible because of the potential retinal detachment. Your retina specialist will give you all the details for your individual circumstance after an examination.

Another issue to which I take extreme exception on the Visian is that it must be supported by being placed in a small ridge that is just behind your retina. If this ridge is wider than the size of the Visian, then it will "float" around and will easily cause trauma to the crystalline lens. The method used by most doctors (and approved by the FDA) is to measure the "white to white" of the cornea, which has absolutely no bearing upon the size of the underlying ridge. To be accurate, a special ultrasonic measurement must be made and few surgeons have this equipment.

Yet another issue with any P-IOL is endothelium cell loss. A certain amount of endothelial cells need to remain healthy to keep the cornea nourished. We all lose endothelial cells as part of the aging process, but virtually all studies show that all P-IOLs induce endothelial cell loss and accelerate loss in the ensuing years. Our organization argued strongly for the FDA to recognize this issue and the currently FDA approved method is for the doctor to take a count of the endothelial cells in a square millimeter and compare this count to a sliding scale of anticipated loss and expected time the P-IOL will be implanted. If you don't have enough cells to start, the P-IOL is contraindicated. At some point in time the number of cells will be diminished to where safety is a concern and the P-IOL will need to be removed. What fries my eggs is that very few surgeons implanting the P-IOLs are doing the preoperative endothelial cell count and even fewer have requiring the patient return on a regular basis, such as every year, for a count to be certain that the endothelial cell loss is not accelerating too much and the original time-line is still correct. And even fewer doctors are telling patients that on or about a particular date the P-IOL will need to be removed because of anticipated cell loss.

Don't get me wrong. P-IOLs are sometimes the very best method of surgical vision correction, but all these measurements and cell counts must be performed or the doctor is, quite literally, shooting in the dark.

Let's talk about why you would consider P-IOLs instead of RLE in the first place.

A P-IOL is a "helper lens" because it is placed in front of the crystalline lens within the eye. The natural lens is still able to accommodate. Accommodation is the process of natural crystalline lens changes that allow you to focus on near and intermediate distant objects. This is great for a young patient, but you may not have all that much accommodation remaining, and in the next few years even that accommodation is likely to be lost. You probably need reading glasses or bifocals now, and they are probably about 1.50 diopters in power (reading glasses) or add (bifocal). The actual amount of accommodation you may still have can be measured by comparing a manifest refraction (which is better, one or two?) with a cycloplegic refraction (which is better with the crystalline lens temporary paralyzed and the eyes dilated) or other similar methods.

RLE removes the natural crystalline lens within the eye and replaces it with an artificial lens. The artificial intraocular lens (IOL) will be of a refractive power to reduce your need for corrective lenses. Because the crystalline lens is removed, all accommodation is lost. If you have accommodation, this is an important consideration. If you have little or no accommodation, then it is not an issue for RLE at all and there really is little reason to even consider a P-IOL...just do the RLE.

In my opinion, (I am not a doctor), if you have little or no accommodation, then a P-IOL is just so much expensive baggage, will need to be removed, will require additional surgery, will reduce the health of your cornea (although not necessarily to a point of instability), and means multiple surgeries rather than one.

Although RLE may sound like the best way to go, that is not necessarily correct. Cataract surgery is relatively traumatic to the eye and a compromised retina may detach. Your independent retinal specialist needs to take a good look and evaluate if you may want to avoid any surgery of any kind as long as possible, or if either P-IOL or RLE may be appropriate.

Lastly, let me make a prediction: if you elect or RLE, the surgeon will tell you of the "wonders" of accommodating IOLs that will enable you to see near, intermediate, and distant objects without glasses. When (if) you get that far, come back and we will have a discussion about the presbyopia correcting IOLs, aka premium lenses.
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Re: IOLs, two opinions, two recommendations, more confused

Postby alake » Mon Nov 30, 2009 3:50 pm

Thanks for such a detailed response. The second surgeon did do the endothelial cell count and he was the one who said he would not do the Visian implant. I believe he told me much of what you said in your response which makes me more inclined to trust his judgment.

Assuming I have ruled out Visian and am only going to consider lens replacement, I have another couple of questions. I have read a bit about multi-focal lenses, which the surgeon recommended. It sounds like the multi-focals are a compromise and increase the chance of halos. I would be more inclined to get a single focus lens and wear glasses. My goal is not to be glasses free, but to be able to function without glasses if need be. I'd be interested on hearing your opinion on the single vs. multi-focal lenses.

Lastly, I asked both surgeons about having surgery in one eye only and continuing to wear glasses. Both said that glasses make things look smaller and the difference between the corrected and uncorrected eye causes some confusion for the brain. This makes sense to me if I'm going to be glasses free. But if I'm going to need glasses anyway for reading and perhaps for astigmatism or further correction, why would it make any difference? Again, my goal is to be able to function without glasses but not necessarily to completely eliminate them (I was in a car crash where my glasses came off. It was quite scary not being able to see and not being able to find my glasses. I always have a spare pair in the glove compartment now but this is one of the experiences that make me want the surgery). Don't people with cataracts in one eye just have surgery in one eye? I suspect yes if insurance won't pay for the second especially. If I knew I could do the lens replacement in one eye now and just wait for the other to develop cataracts in 10 or 20 years I would be much more comfortable having the surgery. Any thought on this?

Thanks again for the information you provided.
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Re: IOLs, two opinions, two recommendations, more confused

Postby LasikExpert » Tue Dec 01, 2009 6:05 am

alake wrote:It sounds like the multi-focals are a compromise and increase the chance of halos. I would be more inclined to get a single focus lens and wear glasses.


Not an increased chance, an absolute probability. The question is not if you will have halos, you will, the question is if the halos will be bad enough that they are not worth the added convenience of a reduced need for reading glasses.

alake wrote:My goal is not to be glasses free, but to be able to function without glasses if need be.


This is a reasonable and attainable goal. You can be able to function and have excellent vision at some distance, but not at all distances.

alake wrote:I'd be interested on hearing your opinion on the single vs. multi-focal lenses


There are two kinds of presbyopia correcting IOLs. The multifocal and the pseudo-accommodating lens.

Think of a multifocal lens as being a bullseye target with concentric rings. Each ring provide focus for a different distance; near, mid-distance, and far. If all rings are equal in influence, then at any time 2/3rds of the light entering your eye will not be focused for the object at that distance. If the object is near, the 1/3rd that is focused for near objects will provide good optics, but the ring for mid-distance and for far will be out of focus. This is the simple physics of multifocal lenses. Manufacturers try to work with changing pupil sizes and different balances, but the bottom line is that some - probably a majority - of the light entering the eye will not be focused. This can present as blurred vision, hazy vision, halos, etc.

The pseudo-accommodating IOL in the US is the CrystaLens. It is designed to vault forward and move back with activation of the same muscles that would have changed the shape of the natural crystalline lens. The big advantage of the CrystaLens is that all of its optics are set for a single focus. It is a mono-focus lens that moves to change focus and provide some accommodation. The disadvantage is that the CrystaLens does not always provide pseudo-accommodation. You could end up with a rather expensive mono-focus lens if it is not able to accommodate, and there is no way to know if it will accommodate until after implantation and a few months of healing.

The alternative not discussed is monovision, which you can try with contact lenses now and decide if that is the way to go.

alake wrote:Lastly, I asked both surgeons about having surgery in one eye only and continuing to wear glasses. Both said that glasses make things look smaller and the difference between the corrected and uncorrected eye causes some confusion for the brain.


This is especially true for someone with high myopia. Contact lenses are less problematic.

alake wrote:But if I'm going to need glasses anyway for reading and perhaps for astigmatism or further correction, why would it make any difference?


The imbalance between the eye fully corrected with an IOL and the eye corrected with glasses would be significant, leading to aniseikonia and poor vision quality.


alake wrote:Don't people with cataracts in one eye just have surgery in one eye? I suspect yes if insurance won't pay for the second especially.


In that situation the IOL for the corrected eye would be of a power to keep the eye in the same refractive state as before surgery. In other words, high myopia before surgery and high myopia after surgery. That is not your goal at this point in your life.
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Re: IOLs, two opinions, two recommendations, more confused

Postby alake » Tue Dec 01, 2009 2:46 pm

Thanks again for such a detailed response. I looked again at your first response and noticed the part about the ultrasound. The second surgeon did do that particular exam. He was very clear that Visian wouldn't be appropriate. As far as the lenses, the first does they Crystalens and the second the Tecnis and I'm sure both do single focus. Well, it sounds like I probably won't be doing this at least not until I develop cataracts. I just can't see removing healthy albeit aging and highly myopic lenses. I could see doing one but your explanation helps me understand the reason that really doesn't work. One last question. Do you think there's any implant, which leaves the natural lens in place, in development that might work in this sort of situation. I would guess not.
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Re: IOLs, two opinions, two recommendations, more confused

Postby LasikExpert » Tue Dec 01, 2009 4:48 pm

alake wrote:Do you think there's any implant, which leaves the natural lens in place, in development that might work in this sort of situation. I would guess not.


I have no doubt that doctors and technicians are working on improving existing technology and advancing new ideas, but there is nothing that I know is in development that is going to be able to circumvent the laws of physics and optics. A P-IOL takes up room and any foreign object in that part of the eye has consequences. Those consequences can be reasonably measured, evaluated, and predicted to allow for a degree of safety. Many have tried to build a better multifocal lens, but all run into the same issue of multiple optics. If you decide to not have vision correction surgery now, then be sure to revisit the idea in a couple of years. It is always amazing what can be discovered.

Once presbyopia has reduced your ability to focus on near objects, every response is a trade-off. You will gain something, but you will lose something too. What is an acceptable trade-off depends upon the requirements of the individual patient.

I recommend that you do get that retinal exam. Being highly myopic, you are susceptible to retina problems. Your retina health should be regularly monitored. I also recommend that you try monovision with contacts. At some point you will require cataract surgery and it would be good to know if monovision is acceptable.
Glenn Hagele
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USAEyes

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