Unfocused vision after cataract surgery

[Agsurfer]

I had cataract surgery on my left eye a couple of weeks ago and was implanted with a Tecnis monofocal IOL with a diopter power of about 15. The plan was for the eye to have a focus distance of around 20 inches, but it actually focuses best around the 11 inch mark. To me, this seems to be a pretty large margin of error. Has anyone had a similar  experience?
The second question I have relates to the clarity of vision I get from the IOL in my left eye. Although the IOL produces much more vivid colors than I saw before the surgery, the clarity is lacking -- even though my left eye focuses "best" around the 11 inch mark, my vision is still not clear even at that "best" point -- it still seems unfocused. For example, it's not easy to read newsprint with the left eye because the text is not crisp and clear enough to scan quickly. Again, has anyone had a similar experience and -- most important -- is my left eye vision focus likely to improve?
I'm a 72 year-old male in good health

[micheleshari]

I had the tecnis 3.25 IOL implanted in both eyes in December 2016, with post-op YAG and PRK for a R astigmatism. I still can't see clearly and my problems are identical to yours-I can see at 20/30 but not clealy, can't scan print and have "vaseline vision", halos and starbursts. The eye MD said the lenses need to come out. I am terrified as he did the YAG even though he knew I was having problems (I am an RN and was very clear and vocal about my complaints). I was realistic going in and only wore glasses for distance with excellent near vision and didn't care if I needed reading glasses post-op. I am now in a real mess and don't quite know what to do.

[JohnHaganMD]

Do you mean a tecnis toric IOL of 3.25 diopter cylinder? I would start by getting 2nd and 3rd opinions by ophthalmologists that specialize in cornea/refractive/IOL/Cataract and post cataract surgery complications. You obviously need the opinion of more than your surgeon before deciding to do IOL exchange.

[Agsurfer]

Well, I was just asking what was the meaning of the 15 D for the implanted IOL. That means it's got a focal length of 2.6 inches. Now, that may mean something to you as an eye specialist but it doesn't mean much to me. I asked the question because I was interested in knowing the answer. Searching Medhelp gave me some fragments of information but no clear answer and looking up optics in Wikipedia wasn't much help, either.

You missed my point about the clarity of vision. I know I'll need bifocal glasses to see at different distances with a monofocal IOL. However, my point was that if text is still blurry without glasses at the 11 inch mark (the IOL focal point), then any images I see through glasses are going to have the same degree of blurriness.

[John C Hagan III, MD, FACS, FAAO]

I do not have time to explain optics. The sections on Wikipedia are best. Progressive bifocals will have variable focal lengths and enable you to see well at all distances (assuming the rest of your eyes are healthy).  With monofocal IOLS it should always be assumed that you will need a multifocal glasses to see best at different distances. Even patients who opt for much more expensive multifocal/accommodating IOL still need glasses for many things.

JCH MD

[Agsurfer]

Thanks for the response. I had read quite a lot of posts over the past two weeks and had gotten the relationship between diopter correction and the distance from the eye to the clear vision point (e.g., 1.0 D correction = 100 cm, or about 39 inches; 2.0 D correction = 50 cm, or about 20 inches; 3.25 D correction = 30.8 cm, or about 12 inches).

The plan for my eye was to produce a focus distance of about 20 inches, or a correction of 2.0 diopters. With an error of the size you cite, +/- 0.5 diopters, that would result in a post-operative focus distance somewhere in the range from 2.5 to 1.5 diopters, or between 16 and 26 inches. Since my eye ended up with a focus distance of about 11 inches, that translates to a correction of 3.5 diopters, or 1.5 diopters off the target. That's far beyond the +/- 0.5 diopter errror range that you cite. As I said in my original post,  " this seems to be a pretty large margin of error."

By the way, if the corrections are in diopters, what does the 15 D correction mean that's on my IOL implant card? I assumed it was diopters but that doesn't make sense in light of the corrections noted above.

Any comments on my second question, which relates to the fact that the vision through the IOL is unfocused, even at the 11 inch "best focus" distance? My eye has now had long enough to recover from the lens implant operation but I still can't read easily with that eye. My concern is that if the implanted lens doesn't provide good focus at the focal length of the lens,  I don't think a bifocal lens in front of it is going to make the focus any better at other distances.

[John C Hagan III, MD, FACS, FAAO]

The forumula for determining IOL power and post operative refractive errors are not exact formula and even using the best instruments and forumula have an plus/minus error of 0.50 diopter.

There are plenty of discussions of IOL power determinations and post operative observations. You can access these with the searach and archives.

JCH MD