Monofocal lens options

[mc1959]

BACKGROUND
I am very nearsighted (-8 diopter).  I will soon be having cataract surgery in both eyes. Several doctors strongly advised to consider only monofocal lenses, as opposed to newer and more expensive options.  I am fine with that.

The tough decision I need to to make is whether to correct for near vision or distance vision.  Having once unsuccessfully trying contacts with one eye corrected for near and the other for distance, I have ruled out that option.  My doctors and most websites I have visited say that 80-90% of cataract choose distance vision correction, and may require reading glasses for near vision.  The sources also say you can be corrected for near vision, but will need glasses for distance. I am leaning towards correcting for near vision

QUESTIONS
1.  If corrected for near vision, will my distance vision still significantly improve (I am about 20/200 vision) to the point where I can function well most of the time without glasses? I understand I would likely need to wear glasses for driving

2.  Does anyone have personal or professional experience with patients choosing this option?  If yes, are such patients any more likely to be happier or more dissatisfied than those choosing distance correction?

3. Any other tips, questions or suggestions on how to choose the best option?

Thanks in advance

Mike    

[wanlien3]

Before we get carried away, a la road rage, for instance, let's revisit my first post:

To summarise
Reconsider your multifocal options, especially if you live in a place or near a place where the newer presbyopia lenses are available. Bear in mind, older multifocals do give obvious halos and accommodating lenses don't work reliably, but the Symfony in particular is showing a lot of promise.

With monofocals, consider what is the activity you would most like to do without glasses.
eg
driving-go for full distance correction and wear readers for near
Computer-go for low myopia -1D and wear distance glasses, and occasionally readers if necessary
Reading-go for more myopia-1.5D to -1.75D and wear distance glasses

Monofocals are always an option, I am not against them. It is up to the individual to decide whether they want multifocals or monofocals, and in order to obtain informed consent they need to know all about the pros and cons of each option. My concern is that this may not have been communicated fully to the person involved, in particular he may not have been appraised of new technology.

In any case, EDOF lenses are much less risky than accommodating lenses of any sort. The Symfony for example is based on the FDA approved Tecnis platform, and uses the same FDA approved material. There is basically no cause for concern about late problems, since any problems are going to be optical and are going to be obvious straight after surgery.

There are no articles in peer reviewed journal articles yet, but these are initial studies on the EDOF lens:

http://bmctoday.net/crstodayeurope/2014/10/article.asp?f=early-results-with-the-symfony-iol
The above includes a study comparing EDOF with trifocal with monofocal. The EDOF lens was better with defocus testing and contrast testing than the other 2 lenses.

http://www.tecnisiol.com/eu/tecnis-symfony-iol.htm
The above is company data, taken with a pinch of salt, but which shows no increase in halos compared with a monofocal.

When I say newer EDOF lenses are different to older multifocal lenses, I mean that they do not cause the side effects and other optical problems of older multifocals, in particular there is no drop in intermediate vision, there is no loss of contrast, and there are no halos around light sources.

As to how the Symfony works, you can look up US patent 8747466 on Google patents. The Symfony tweaks the diameter of the central refractive zone versus the dioptric difference between the diffractive orders, in order to extended the focal range. They also blaze the echelettes on the diffractive grating to maximise the effect of the involved diffractive orders.

So although it looks like just another diffractive multifocal, it is a very different lens. Typically the older multifocals had a big dioptric difference between the diffractive orders, as they wanted to separate the near and far foci as much as possible. This causes two problems, among others. First, loss of intermediate vision. Second, the defocused image was a huge blur thus causing the halo around light sources. These, among other reasons, were why they were never very popular and suffered a higher explantation rate than monofocals.

Yes, having +4D glasses on, walking around is no problem. I am -6D right and -9D left and I walk around perfectly fine without glasses or contacts on. But I would not be able to read the top letter on the chart at 20 feet. My vision is count fingers unaided at 20 feet, as would that of somebody with -3 or -4D.

If you look up any optometric or ophthalmicbook, especially on refraction, the general guideline for unaided vision is 20/60 for -1D (spherical equivalent), 20/100 for -2D, and after that it is 20/200 or count fingers. That is one of the ways that optometrists and ophthalmologists can estimate refractive error based on unaided vision (assuming no other ocular pathology).

Just because one may have had a difficult experience with a lens like the Synchrony does not mean that all the other new lenses are going to be like that.

For the EDOF lenses, surgery is exactly like routine surgery, the implantation is just like implanting a monofocal lens, so there is absolutely no increased risk for a high myope. Even the A constant used in calculating IOL power using the SRK/T formula is the same as a monofocal, so there are no issues with post operative refractive predictability.

The lens material of the Symfony is also hydrophobic acrylic, with a sharp posterior lens edge, which are factors which reduce the incidence of posterior capsule opacification. Which is a good thing for high myopes, since you lessen the risk of needing YAG capsulotomy, which is associated with a small risk of retinal holes and detachment.

[etrader]

Once again there are too many armchair experts here offering you advice, it may be well intentioned but it is not a substitute for an expert opinion from a surgeon.

You need to go to see a couple of consultants and ask their expert opinion.

[KayakerNC]

You say; "The newer Extended Depth Of Focus (EDOF) lenses like the Symfony are nothing like the older multifocal lenses."
Do you have anything that would substantiate that claim?   Because, from here, it appears to be a modified TECNIS multifocal IOL, similar to the ReSTOR 2.5 (awaiting FDA approval) also modified to improve intermediate vision.

[Anomalychick]

I disagree with that. If I put on my boyfriends +4.00 glasses I can still see well enough to walk around. (at a -4.00) 1 Diopter really does account for about 2 lines on the eye chart, ask an eye doctor. If this person is 20/200 right now with a -8, they would  have less than half of that refractive error. Which means their distance vision should be twice as good with a -3.00.

To the test the theory, let them find out for themselves. If your prescription is -8.00, ask your doctor to try a pair of -5.00 contact lenses or glasses. That will leave you with a -3.00, so you can see what your distance vision will be like. Of course,  if the cataracts are affecting your vision at this point, you'll need to use your imagination and pretend they aren't. The blur caused by cataract is different from the blur caused by refractive error so you should at least be able to get an idea.

Furtheremore, I do understand that extended depth of field is all the rage. It does cause a sacrifice to visual quality and its NEW. There is a risk wth anything new, because you don't know what the long term effects are going to be. If someone doesn't really care if they need reading glasses, why should they subject themselves to the risk and and the expense and the inconvenience? I understand that better vision may be a realist option, but plenty of people are perfectly happy with monofocals. (I wouldn't be one of them, but plenty of people are.) I would never recommend a premium lens be it multifocal accomodating extended depth of field or whatever to anyone who would be perfectly happy wth monofocals. Also, high myopes like this person are subject to a slightly higher rate of complications to begin with and should take that into consideration. Monofocals are cheaper than premium, have a lower rate of complications than premium, and are tested tried and true.If someone is motivated to avoid glasses then by all means, there are ways around it. But it seemed this poster didn't really care.

[wanlien3]

The newer Extended Depth Of Focus (EDOF) lenses like the Symfony are nothing like the older multifocal lenses. They don't cause halos, they are much more forgiving of small biometry errors and they don't cause blurred intermediate vision. They are not perfect, and very close up vision is not as good as a natural high myope's, but vision over a range of distances from far to intermediate is very good, and near is good enough for reading without glasses for many people too. As this lens is optimized for far to intermediate distances, reading glasses of a low power eg +1D may be needed sometimes.

Over the next few years, you will see a whole range of EDOF lenses coming out from every major manufacturer. AMO has started the ball rollling, Hoya has one, and soon it will be Alcon and Staar as well.

These EDOF lenses also don't cause the refraction to shift around like what can happen with accommodating lenses such as the Synchrony. The Synchrony and the Symfony are completely different lenses, even though they sound alike.

-3D is a pretty high myopic error to set, even for somebody who wants to read comfortably. For distance, a -3D myope would see something like 20/200 to count fingers, believe me, it is that bad. Once you go beyond about -2.5 or so, there isn't much difference in the distance vision, ie for -3, or -4, or -5 distance vision is just a blur.

[Anomalychick]

If you are comfortable with monofocals I would NOT recommend going with one of the newer IOLs. You need to be motivated to avoid reading glasses to risk it. If you don't mind being fully presbyopic, then don't worry about it.
If you set your eyes to PERFECT near vision youd want about a -3.00. For every diopter off, you lose approximately 2 lines on the distance chart. So for 3 diopters, your distance vision would be between 20/60 and 20/100 depending on how much depth of field you end up with. You can't drive with that, and you probably wouldn't like watching TV very much. You most likely wouldn't have a problem "functioning." Just, forget about reading signs or seeing what anything is clearly until you get really close to it. You'd need to lean in to use the computer. But you're not going to have a hard time walking around, your vision needs to be REALLY bad before that happens.
    
I should warn you though, -3.00 isn't quite as good as a -8.00. I mean, I  personally thought -3.00 was almost obnoxiously clear close up after my cataract surgery, I felt like superman, but I was not nearsighted before. I didn't have any complaints about my near vision at -2.00 either though. At    -1.50 I had some difficulty in dim light but not otherwise. (I have a different IOL, my prescription shifted all over the place so I have personal experience with everything from a -3 to a +1) The perfect vision you now have 2 inches from your eyeball will be gone.

Given that you are currently a -8.00, your distance vision would be much better than it was when you weren't wearing your glasses pre cataract. I've heard that nearsighted people often choose to remain nearsighted. The ones that go for distance vision are often somewhat traumatized by the loss of close up vision which is what they've been really good at their whole lives.

[wanlien3]

First of all, you might want to revisit the reasons why the doctors advised monofocal lenses. If an important reason is with regard to halos with multifocal lenses, then there is a new extended range of vision lens called the Symfony lens by AMO that allows good far and near vision without glasses and also without the halos of older multifocal lenses. (this is only available in Europe and parts of Asia like Singapore and Hong Kong at this time)

But assuming you are set on monofocals, how good your distance vision will be depends on the target refraction you aim for. The better the distance is, the worse the near gets, so it is a fine balance that depends on what your usual activities are.

If you spend a lot of time with computers and would like good middle distance vision with monofocal lenses, you should target about -1D of myopia, which gives perfect focus at 1 meter. This will give you 20/60 or 6/18 distance vision without glasses, which is not quite good enough for driving but better than what you have at the moment. You will need distance glasses, and perhaps sometimes reading glasses too for really fine print.

If you do a lot of outdoor activities and would like to drive without glasses, then you should aim for near zero power and wear reading glasses for close up vision. This could take some getting used to if you do not have experience with contact lenses and reading glasses before.

To summarise
Reconsider your multifocal options, especially if you live in a place or near a place where the newer presbyopia lenses are available. Bear in mind, older multifocals do give obvious halos and accommodating lenses don't work reliably, but the Symfony in particular is showing a lot of promise.

With monofocals, consider what is the activity you would most like to do without glasses.
eg
driving-go for full distance correction and wear readers for near
Computer-go for low myopia -1D and wear distance glasses, and occasionally readers if necessary
Reading-go for more myopia-1.5D to -1.75D and wear distance glasses