Unhappy With 20/20 Vision After Cataract Surgery?
Removing the lens from an expensive camera renders it useless - the same goes for the eyeball. Cataract surgery subtracts a whopping 18 diopters of focusing power from the normal adult eye. That is approximately one-third of the eye's focusing ability. Eye surgeons compensate for this loss with implantation of an artificial intraocular lens (IOL).
Over the last 30 years there have been tremendous improvements in IOL materials and optical design, so much so that implantation of an ordinary IOL generated dissatisfaction among some recipients. These unhappy individuals could see the 20/20 line on the eye chart but claimed the vision was inferior to the kind of eyesight they experienced prior to cataract formation. Sometimes they said unkind things to the doctor. Were they just too picky?
Today we recognize that patient post-op expectations outpaced IOL technology. Those cranky patients were right! Sure they could see the 20/20 line but their vision fluctuated in different lighting conditions. Contrast sensitivity, a superior method of assessing visual function, was markedly diminished. Back in 1980 anything approaching a 20/20 outcome was cause for celebration. Today it takes more to make folks happy.
What was the explanation for the unsatisfactory post-op vision? A lot of it is attributed to something called spherical aberration. No man-made lens is perfect (spectacle, contact lens, IOL). The optics may be precise at dead center but as you travel towards the outer edge of the lens the focusing can change dramatically. Spherical aberration (SA) distorts and degrades the visual image. To make things worse SA is magnified in high-power lenses like an +18 diopter IOL. In dim light the pupil enlarges and that also exposes the eye's visual system to more SA. Finally, if the IOL shifts the tiniest bit (decentration or IOL tilt) there can be an abrupt loss of crisp vision because the center of the IOL is no longer aligned with the visual axis.
Mother Nature's lenses aren't much better. The natural lens has measurable minus-power SA; however the clear cornea compensates for this situation with it's own plus-power SA. So, even if the surgeon precisely implants an optically perfect IOL the eye still has to deal with leftover positive-power SA from the cornea. Getting bleary-eyed yet?
The current solution for this dilemna is Aspheric IOLs. They have brand names like Technis, Acrysof IQ, and Sofport AO. These IOLs have restored the minus-powered SA that was present in the natural pre-cataract lens so that the net effect is minimal post-op spherical aberration.
If you got this far I must congratulate you for your intellectual curiosity! Patients receiving Aspheric IOLs report an extraordinarily crisp visual image. All they want to know is, "Doc, when can you do my other eye?" That's the nicest thing anyone can say to an ophthalmologist!
Related Topics: Technorati Tags: cataract, spherical aberration, 20/20, vision
10 Comments:
Reading this article made me wonder if this is what I'm going through. I had lens replacement surgery at an eye center in Detroit last year. I initially went there to see if I was a candidate for lasik surgery. Alas, I was not. My vision in my right eye was 20/200, and they told me that I would most likely have to have cataract surgery in the near future. I was very adamant about some kind of immediate solution. They told me that the only alternative would be lens replacement surgery. I was very reluctant and disappointed at first because this was VERY expensive surgery, especially since I had to have both eyes done. Well, after convincing my husband that this was very important to me and telling him that I would be a happier person if I could regain my vision, we scraped up the money and went ahead with the surgery. Now it's a year later and I'm struggling with my vision. They prewarned me that I would forever see "halos" around lights at night, such as street lights and headlights, so I knew about that and that is the case. When I went back for my follow-up visit after the surgery I had to get a touch up because I had some scar tissue on my eyes after the surgery. They never told me that my eyes might go back to how they were. I haven't been back since and my eyes are steadily getting worse. I work on a computer at work and I struggle trying to focus. I feel like I'm back to square one, except for the fact that I can see better from a distance. Otherwise I have to be at a certain distance to see good enough to read something. I almost feel like I need reading glasses again. I'm very disappointed, and I don't know if I should try and make them fix me, if they even could, or deal with the fact that this is as good as it gets. I wouldn't advise anyone to get the surgery that I had done, but that's just my opinion.
hello, i had cataract surgery in 2004, as a 24 year old. until i was 21, i had perfect vision. and then it steadily decreased. i had the surgery in both eyes. for me, it was great. my surgery went well. and although i DO need reading glasses. and distance. my sight is much better. i was legally blind in one eye due to glare and headed there in the other.
maybe i can shed some light on the above person's experience. getting a lens implant makes your eyes even more like a camera. your eyes can no longer focus. they have one point of focus. that's usually set as distance vision for most patients. my opthamalogist and i decided to set mine closer because i study photography and do a lot of close up work.
my eyes focus well at arms's length. i use +1.25 readers. i was prescribed progressive bifocals but they gave me horrible migraines. it wasn't long before i stopped bothering. i tried contacts. but taking them out at night was incredibly painful and time consuming. at this point i just use readers and my "natural" vision. and distance lenses when i need to. which isn't often. i don't drive.
anyhow, when i had my surgery, the multi-focal implants were just coming to the market. when i asked about them, i was told about the halos. because of what i do, i decided against them.
i don't know if the above person got that variety of lens. i got single focus iols.
it's not only the aberration of the lenses and cornea that cause the blurring. it's a simple matter of depth of field. your iris becomes like the aperture ring of a camera. in low light that ring opens up to let in more light. when that opening enlarges, it lets in more light, but that light isn't as focused on your retina. therefore, for your vision to be crisp, you have to be able to focus on what your looking at. there isn'y much behind or in front of your point of focus that will be clear.
with natural lenses your eyes would focus on what you are trying to look at and things would come into focus. when you have implants they can't. there is a very narrow field of focused vision in low light. out of focus points of light will have halos. just like in a picture.
during the day this isn't as much of a problem because your irises aren't as open. more things stay in focus. no bright points of light to cause halos.
i've just come to accept it as that way it is. in 20-30 years, i may have to get the lenses replaced. who knows what the technology will be then. my contrast and my vision improved greatly with the surgery. i could actually manually focus a camera again. :) understanding the optics of the eye and relating that to photography really helped me to understand what was going on with my vision.
obviously there is something going on with the above situation that is out of the norm. it sounds like the lenses may have shifted abnormally or more scar tissue is forming. it could be something else entirely. i would suggest getting a thorough eye exam to check for other problems.
i wish you the best of luck.
if anyone else is going through cataract surgery in early adulthood, i'll be more than happy to give my experience. i found almost zero information when i went through it. which was very frustrating to me.
To synthetase-Hello. I am the person who posted the first comment. I want you to know that you really did help me understand SO MUCH about the way that the eye works. The way you explained things in the way the lens works like a camera, I was really enlightened. When I had the surgery, they didn't take the time to give me any information like that. I think that my main problem is that I may have some scar tissue coming back, because now I slightly remember them saying that I might have to come back for future touch-ups. That is the next step that I am going to take. It has been a year and 8 months since my surgery, and like you said it was relatively new still. Looking back, I probably should have had the CK surgery. It sounds like it would've been a better option for me. Who knows the advances they have made with it even in the last 1-2 years! Maybe I should'nt have complained as much as I did. I am still prescription/reading glasses free, and I would say that I see 85% better than I could pre-surgery. But I was hoping for complete 20/20 vision! Thank you for taking the time to respond to my comment. Honestly, your information really was helpful to me.
I had catarat surgery 3 weeks ago, then 4 days later the dr. went back in and adjusted my toric lens for astigmatism. My vision is all distorted, ie, circles are now ovals, I was told I would not even need glasses if I purchased this great Toric lense. Well now I cannot see. I'm 3 weeks post op and looking for another doctor. My vision was not bad, 20/40 when this all started. They are doing this surgery every 3 days in New Jersey and I mean all day long. I really was oblivios to the remifications. Just trusted this man to do a good job. and I paid the additional money for the lense.
Now I can't even see with eye glasses. My distance vision is excellent. Like super man but I can't see to walk. Any suggestions?
i had cataract surgery 4 wks ago and my eye seems like a thin paper runs across the center at times and my eye hurts if i strain to focus too long on a subject,,,should i go to E.R. room?
I had surgery 3 days ago. Although I see 20/25 on the chart, I am looking through 'fog'. I was not prepared for this cloudiness and am wondering if it's normal? I'm supposed to have the other eye done in a few days.. Will I be blind as a bat? How long does it take to clear? I had a 'floppy' iris so surgery was long....
Ann
Hi. I had cataract replacement in my right eye 3 months ago. My left eye is OK. I'm finding it difficult to focus on the ball while playing tennis. Has anybody else got that problem?
My husband had cataract surgery 11 days ago. The surgery went well with no bleeding and no pain. However he now has a complete loss of color in the operated eye and everything looks solarized and blurred. While the doctor says that his vision is 20/40, that is only in the examining room and not in the real world where everything is a blur. Low light situations, while blurred, are better but sunlight situations almost completely eliminate vision in the operated eye.
The doctor who has performed 2000 cataract surgeries is at a loss for an explanation especially as the optic nerve is intact and undamaged.
He was supposed to have surgery on his other eye but, of course, will not take a chance on losing the sight in that eye as well.
I am concerned about the sales efforts going on now in many ophthalmology practices. They say they are just educating patients on the benefits of multifocal implants, but all the videos, brochures etc. are on multifocal. Then the doctor comes in and recommends, you guessed it, multifocal implants. Monofocal is being described as inferior government issued implants. The IOL Counselor video now being used shows multifocal scenes as fully visable and clear, while showing monofocal scenes as totally blurry.
Some practices claim their conversions rates are now up to 80% for multifocal. Linda Wilson
I had cataract surgery 5 days ago. I am not a 'man of means at all' and at 58 years old, could only get my insurance company to pay for the cheapest lens ($75.00) but the surgery clinic wanted 300 bucks out of pocket(my food budget for 2 months)..The surgeon has a GOD complex & treated me like something he forgot to wipe off his feet that he picked up off the lawn.Definitely not a "people-person type of guy..but world famous" ..Went in the next day with fully dialated pupil & couldn't see my hand in front of my face. Now, 4 days later the eye I had surgery on is all a blur. I call them up and they get mad at me for 'bothering them or even suggesting they are "fallible" and could have made a mistake. This is posted as a Warning:Do Not Go 'Blindly' -no pun intended- into Cataract Surgery. Even 'God MDs famous in their field' make LOTS of mistakes. I Can't afford a lawyer to sue; I can't afford followup surgery. I'm what they call..SCREWED.
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