symfony lens

Thank you for your information.  My doctor seems to think I would be better off with the Symfony.  I am not 100% convinced because I have always been visually sensitive to light and shadows when playing tennis.  Do you know anything about the Tecnis HD lens that is not FDA approved yet?

I'm not quite sure what you mean by "visually sensitive to light and shadows". Do you usually play in daylight or at night under lights? Some of the studies show the Symfony as having comparable contrast sensitivy to the high quality Tecnis monofocal control lens, while others put it only slightly below that and still within the range of the age matched population (though I think the comparison was for those older than 60, I hadn't seen a direct one for those of us under that). The chromatic aberration correction unique to the Symfony tends to balance out the aspect of the optics that extends the depth of focus to provide decent contrast sensitivity. 

Contrast sensitivity does vary even among those the same age. I had one puzzling comparison with someone who lives here who got the Crystalens, and being also a science/tech type he wrote up the experience in detail. We compared notes in a well lighted auditorium after a lecture and he held a file folder over a near vision chart to cast a shadow and said it reduced his near vision by some lines, but it didn't make a difference to me. We are about the same age, but it could be individual variations rather than the IOL, but unfortunately I hadn't seen a direct study comparing the two for contrast sensitivity (or even visual acuity that I can recall). The Crystalens is a single focus lens, that may accommodate, so I hadn't expected that (oddly studies also suggest it might have a higher incidence of night vision artifacts than the Symfony as well). 

 

Is "Tecnis HD" the actual model name of the lens, where did you see that? A quick search turns up no hits for that. I'd almost wonder if the HD is meant to just to be describing the lens as "high definition" and might be someone's marketing description of the Symfony, or for their apsheric  monofocal, but of course those are now FDA approved. (but for a couple of years the Symfony was   available elsehwere but not in the US so many old articles likely still refer to it as not being FDA approved).

If it is a new lens, I'd be curious to check on it if you can find out a model number or name.  I guess partly since I was an early adopter of the Symfony (getting it in Europe  a couple of years ago before it was approved in the US) I tend to follow literature about IOLs to see if the later studies confirm I made the right choice (so far they have), to answer questions for other folks,     and in case some new IOL ever appears worth risking a lens exchange. 

 

Visually sensitive means my eyes don't adjust quickly to light and shadows.  I have had migraines since I was a kid so that could be a reason for my sensitivty to light.  I just rechecked the name of the lens with a friend who told me about it...Tetraflex HD.  Have you heard of it?

I'm not sure in terms of adjusting quickly to light and shadows how that would compare. In terms of "sensitivity to light", I will note that after cataract surgery with *any* IOL people tend to report being sensitive to light for a while  until they adapt  since their cloudy lens has been replaced with an IOL that lets more light through. I turned the brightness on my computer monitors all the way down to 0, and really needed sunglasses more (as opposed to it just being good to protect from UV).   Again, this aspect likely doesn't vary much if at all between IOLs since they all let in more light than the cloudy natural lens did.

I noticed though from the start however that in one sense I was less sensitive to light in that I had less glare disability from headlights. For some reason  their brightness is much less distracting for me than I can remember even compared to before I had cataracts, the brightness doesn't cause the same difficulty it used to seeing surrounding objects. I don't know if this is anything specific to the Symfony, or merely having an IOL.

The Tetraflex is an accommodating lens which seems to be less used than the Crystalens even where it is approved, so I get the sense its results aren't as good. Its been out for a few years, and I think they'd applied to the FDA (but I'm not positive) since its an American company, so the lack of approval is puzzling. I only see limited data on it, with one study indicating:

"The Tetraflex HD IOLs showed improved best corrected distance visual acuity in comparison to the Tetraflex IOL -0.04±0.08logMAR to -0.04±0.07logMAR. BCNVA was marginally better for the tetraflex HD 0.44±0.14LogMAR to 0.51±0.11LogMAR. "

That near vision translates to 20/55, which isn't as good as typical Symfony studies which tend to be more like 20/32, with mine being 20/25 at near (uncorrected, actually that seems to be distance corrected near, i.e. when you wear correction to give you the best possible distance correction and then check on what that does to your near vision,  and mine is 20/20 distance corrected near).  The corrected distance vision is also slightly below the results I've seen for the Symfony, which sometimes are around that, but usually seem closer to -0.1 logmar, i.e. 20/16 vs. 20/18 (mine is at least 20/15 uncorrected, that line was easy and they didn't have a line below, and we didn't even check how much better it would be with correction). .However its hard to compare studies directly since the surgical results in terms of how close the lens power was to the target and the patient demographics can vary. I usally feel better making a comparison when there are at least multiple studies to go on, but I don't see much out there about the Tetraflex HD. I don't know anything about its contrast sensitivity,  risk of night vision artifacts (the Crystalens seems possibly to have a higher risk of halos than the Symfony, though that I've seen no direct study comparing both lenses in the same study), or if it suffers from any of the rare, but still concerning, side effects like the Crystalens regarding things like z-syndrom or some people not seeing any accommodation and their visual range being more like a monofocal.