Unfortunately there isn't a good description of what these "extended depth of focus" lenses do, so some people are confusing the Symfony with standard multifocal lenses. The issue is perhaps best illustrated by considering photographs. Sometimes you'll see a photograph where only 1 object in the picture is in focus, and the rest of the objects in the background at different distances are a bit blurry. Other times you'll see a photo where even objects at varying distances are all in focus, the photo has a larger "depth of focus". Here are some links to pages which show photos of scenes taken at varied depths of focus to illustrate the point:
The natural eye has some "depth of focus", it doesn't merely see things at 1 exact distance. If you are say looking at someone 6 feet away, your eye is able to see the shape of their face even though say the tip of their nose is a little less than 6 feet away. Even those who have monofocal lens implants can see things that aren't merely at 1 exact distance, there are some things at almost the same distance that are in good enough focus. Someone with a bifocal lens doesn't merely see at say exactly 15 inches, they may see best at that distance but there is some "depth of focus" around that point that lets them see at least some at 12 inches, etc.
The Symfony lens extends the depth of focus so that more distances are in focus at the same time. Since eyes naturally have some depth of focus, the brain is able to adapt to varying degrees of depth of focus.
In contrast, a multifocal lens is doing something that is new to the eye but which people can somehow adapt to, as I did when I wore multifocal contact lenses. 2 or 3 different in focus images for different distances shine on your retina at the same time, and the brain decides which one to pay attention to (in addition to some "depth of focus" around the exact focal points).
Someone suggested I should mention that I do have one uncommon visual side effect that is expected to go away (in 99% of cases), even though as far as I can tell has nothing to do with the particular lens I chose, it could have happened with a standard monofocal. I had hoped it would go away already, although it has subsided a bit. At times it is like what you'll experience in bad fluorescent lighting, things are flickering, though I think its really the image I'm seeing jiggling a bit, especially when trying to read (headache inducing).
There are various potential explanations for the sort of phenomenon which all indicate it should go away within another few weeks as the healing around the lens takes place and I adapt to the lenses (and the explanations don't seem to relate to the type of lens, other than ones which refer to reflections off the lens edge, and this lens is actually designed to reduce those compared to others). Actually I have speculated that it might be not just due to having new lenses, it might relate to another condition that should get better in a short time, myokymia, lower eyelid twitching (barely visible even when you look for it). It only rarely impacts vision but I'm speculating in this initial post-cataract surgery phase while the lens is looser (and I'm not adapted to it) that it might be more likely to jiggle the eye just enough to impact things. I hadn't even noticed it at first, I'd had it a couple of times in the past but it hadn't impacted vision at the time. Its possible that might not be related to the flickering, I'm just speculating and I guess hoping thats it since I know it had gone away in the past. Since its most noticeable when trying to read it may relate to the small fast eye movements made, saccades, during that process.
I am about to get the Symfony in my right eye next week and was really waiting for your response since your last post in December. Happy to hear that all in all things are going fine with your eyes.
In the bottom line - are you satisfied with your decision?
How are glare and halos at night? Do you notice any reduction in contrast relative to your pre-op vision?
I admit I do wonder how what near vision would have been like with a trifocal, but I think this was the right tradeoff for me since it seems like vision at most distances is better than it would be otherwise. I just ran into an abstract for an upcoming conference paper which compares what I assume is the Symfony lens to the various other choices out there, and it says:
"New Extended Focus IOL Versus Bifocal, Trifocal, and Accommodating IOLs
Extended focus lens achieves the best results from 46 cms to farthest vision with no disphotopsic phenomenon and with a great subjective satisfaction."
For Americans, that 46cms is 18.11 inches, and that is only the range where it is better than other lenses, its still decent a bit further in for many people. Here was a good overview article on the Symfony which noted:
"The results presented by Dr. Auffarth were from 82 bilaterally implanted patients with 1-month follow-up. For the group, mean logMAR UCVA was -0.01 for far, 0.03 for intermediate, 0.18 for near (measured at 40 cm), and 0.07 for near at the patient’s best distance, which was about 47 cm. "
Those distance, intermediate, and best nearpoint results convert to about 20/20. The near at 40cm is a little better than 20/32 which is still considered decent vision. Of course people's results vary, those are the averages (though I would guess that those with poorer results would likely get poorer results with any lens since they have other flaws in their visual system).
I am definitely satisfied with my choice (with the caveat that as far as I can tell the flickering side effect has nothing to do with lens choice and will go away, if I'm wrong that is a different story).
I can read my smartphone well and labels at the store, so I see no need to carry readers anyplace (worst case there are magnifier apps for my phone if I ever need to see something small for a minute while out). I have no hobbies involving real close up work, I figure for the rare times I need to see fine detail up close I can use readers, as most people my age would need to.
As many people say with any lens, the world is much brighter after surgery, I actually had to turn my computer monitor brightness down to its lowest setting, 1 (on both brands of monitor I have).
I have no glare issues at all at night, it seems like it is less than I ever had in the past when I needed to wear correction (contacts usually). I am not bothered by halos at all but I can see them now (though I gather they may fade as I adapt to the lenses), I can see through/past them.
Overall my night vision is much better than it was prior to surgery. Cataracts do reduce night vision so that may be part of it (since even my 20/20 correctible eye had a cataract even though it hadn't cut back on visual acuity, and that may have been cutting down on contrast, and my 20/100 eye certainly had less contrast). I also wore a multifocal contact lens before this which probably cut back on night vision though. To the best of my recollection of it, my night vision seems better than it was even before I had cataracts or multifocal contacts, but that may be simply because its been a while and its hard to remember exactly what vision was like a decade ago.
I had the Symfony lens procedure for my left eye at the beginning of December ( in the UK). Unfortunately the lens displaced itself, tilting forward slightly so two weeks later the surgeon redid the op to reposition the lens.
Apparently the astigmatism I had has been corrected (toric lens) but I am now slightly shortsighted (I had hoped for good vision overall). It has been suggested I could have laser surgery to correct this.
My main worry is that I have what I feel is quite bad flaring from car headlights at night and also lots of circles around the lights, presume this is haloing.
I see you talk about haloing and I am wondering if this has diminished/improved for you as time passes after the surgery. I am now three weeks post op from my second op, and I am disappointed that it doesn't seem to be improving
I was due to have the second eye done two weeks after the first but had the correction instead. I am now rather worried that if/when I have the second eye done the haloing etc will mean I am unable to drive at night, which is something I don't want to happen.
I would appreciate your feedback on this unfortunate side effect
Sorry to hear about the lens being displaced (which is of course not related to the optics of this lens, its a surgical issue). It could be that your vision hasn't yet stabilized after your second operation. They usually wait 4 weeks (sometimes even 6) before trying to prescribe correction after surgery to wait for vision to stabilize, and I know mine improved a bit before my 4 week postop. I think I'd read they wait perhaps 3 months before thinking about laser enhancement.
re: the halos. I'd mentioned that I see them, but they don't bother me. My night vision is perhaps better than before I had cataracts, but at the least comparable. The studies show the percentage of those who see halos, and the percentage bothered by them, is very low. It is apparently about the same as with a monofocal lens, since some people can see halos with those as well. In general with all lenses they say side effects like that may appear initially and subside over the first few months, so there is probably a good chance it will get better. Since it isn't an issue for me, I hadn't researched the halo issue, I don't know if perhaps some people are more prone to it and you would be more likely to have halos with any lens, or what the odds are if you have halos in one eye that you will have them in another.
I thought I should add more about the flickering I'd mentioned since it isn't usually mentioned in overviews of cataract surgery or potential visual side effects to indicate why it doesn't seem to be anything to do with this particular lens. I ran into a good free ebook overview of cataracts&surgery which mentions a minor innocuous light version of it some might notice As a side note contains a good writeup of the questionable benefit of laser cataract surgery, though its a couple of years old I don't think there is yet any more evidence to change the general impression. It mentions in passing:
"It's okay to read, but your vision may seem "jiggly". Because the lens capsule has not yet contracted around the IOL, there may be a slight jiggle of the lens with each eye movement. This is most noticeable when reading and will improve over the next few weeks."
In my case it just happens to be more noticeable and long lasting. The eye constantly makes small movements, especially while scanning to read, and the subjective impression of the image jiggling to me appears like the flicker of bad fluorescent lighting. Its likely mostly the lens needing to heal in place but it may be partly the eye&brain adapting to differences from the natural lens (in the case of your natural lens, the brain actually suppresses vision for a fraction of a second while the eye moves and while the natural lens jiggles a bit to a stop).
On this Medhelp its mentioned:
"You also need to know that once your cataractous lens is removed and an IOL placed in the capsular bag, the bag is floppy so to speak. Over a period of six weeks it will encapsulate the IOL or shrink wrap it.
In the meantime you could have what is called pseudophakodonesis which is simply movement of your lens until it settles into place. If you are myopic or have a large eye it would happen more than a hyperopic or small eye. Once the capsule shrinks and it stabilizes it goes away."
This notes that among those where it is bothersome (and I have all the risk factors):
"You may experience some flickering of light or shimmering as the lens implant seats permanently into the capsule of the eye, and this may take up to three months. You may also see some edge glare during the first few months, typically in low levels of illumination.
These symptoms are more common in blue eyed patients, patients with higher levels of preoperative nearsightedness, and patients with large pupils.
Only a very small percentage of patients will notice these symptoms after three months, perhaps less than 1%."
Another source notes that other parts of the visual system can be looser at first as well:
" Your lens is gone and with it goes some of the stabilizing support for your iris. Without it, the iris "jiggles" after saccades. We see it happen in the microscope. Normal, no biggie. "
Although it may be normal to some degree, in some cases like mine it is problematic when reading, but odds are it will go away soon (though it does take longer with a minuscule minority of people who do post around the net, but the odds of it are low).
On the lens itself, I thought I'd note a new paper that shows intermediate vision after 3 months of 20/10 (translating units from their -0.33 logmar), even better than the distance vision of 20/20 (0 logmar) for distance:
" Preliminary results of 30 eyes that completed the 3-month follow-up showed mean monocular UDVA of -0.01±0.10 LogMAR, mean binocular UIVA of -0.33±0.06 LogMAR and mean binocular UNVA of 0.12±0.11 LogMAR. Refractive predictability was excellent with a mean SE refraction of -0.15±0.33 diopters. Contrast sensitivity was similar to published data for a normal population of similar age. 5% of patients complained of mild halos and no patient complained of glare or starbursts. 82 % of patients were completely spectacle independent with 18% needing glasses for near."
It appears from papers I'd seen on multifocal lenses that vision at all distances seems to be improving for the first couple of months especially, and then to some extent for several months afterwards. One doctor who studied the Symfony mentioned in email that the Symfony (with its alternative approach rather than being a multifocal) seems to take longer for neural adaptation than a trifocal, though he hadn't responded to a followup question asking to be more specific and quantify the difference a bit.
One more new article with a good summary of the lens, and the state of others in the works (e.g. the next generation accommodating lenses seem a bit less promising than the impression I'd had in the past) just a clip:
'IOL Alternatives to Multifocality
Avoiding glare and halo while expanding focal depth is the primary goal of these implants.
“The first thing to understand is that the term diffractive optics doesn’t necessarily imply multifocality,” says Daniel Chang, MD, an ophthalmologist from Bakersfield, Calif., who is an investigator for the U.S. trial of the Symfony. “This is not a multifocal lens, but it does use diffractive optics to do two things: First, it corrects chromatic aberration. Second, it uses these optics to extend the range of quality vision.” '
Great to read your recent posts.
I am now 1 week after the surgery in my right eye (Symfony). Left eye clear from cataract - so untouched (myopic: -4.25) - I use a contact lens in this eye.
My results - good distant vision (with good contrast - also at night), intermediate - quite good - I can read a computer screen quite well, near - needs to improve - I can not read a newspaper with my right eye.
Flickering - I also have it sometimes, most of the time not disturbing.
Regarding Halos - I see some around light sources in the night but also not disturbing,
With the contact lens in my left eye - good all around vision (I am 42 - no presbyopia yet).
Bottom line - I am satisfied with my decision to choose the Symphony lens, I still hope that near vision will improve with time.
Thanks for your quick reply. I didn't realise I had to come to the web-page to see replies, thought I might get an email or something!
I saw the surgeon last week, vision, halos etc still seem to be the same. He said my retina is inflamed and gave me additional inflammation reducing eye drops (still using the ones given to me after the surgery) for three weeks.
I have to go back at the beginning of February for a refraction eye test to see how short sighted I am at that time, presumably to assess for laser treatment.
I did read it takes about 3 months for the eye to heal following surgery, so will just have to be patient and hope things improve.
Thank you for your willingness to put forth so much information about the Symfony and your experiences with it. I live in the US and am considering traveling to get the Symfony. I have scanned through many of your posts, but do not recall seeing the name of the doctor who did your procedures. I would appreciate it very much if you would share the doctor you saw and your thoughts about whether you would recommend that doctor to others. I want the best lens put in by the best doctor but am concerned about how to go about making that happen in another country.