My experience of the Symfony Toric lens
Posted , 33 users are following.
I have been short-sighted and astigmatic for most of my life. Finally cataracts meant an operation. Before the operation my myopia was -12.50 (right) and -11.00 (left), astigmatism -6 (right) and -4 (left). I agreed to have a Symphony Toric lens - ZXT375 - and this was inserted into my right eye four days ago.
My vision began to recover from the anaesthesia after a few hours. Other than a dull ache - which lasted no more than 24 hours, there has been little pain. I have been prescribed antibiotic and anti-inflammatory drops four times a day for the next month.
I did not expect that this lens would allow me to read without glasses and (at the moment) it looks like my expectations will be proved right. I have previously experienced halos around car headlights and this is unchanged. In addition I can now see starbursts around some street lights.
I removed the right hand lens from my glasses after the surgery but, having worn them for a short time, found the distortion to be too great. Other than for reading, the vision in my right eye is so much better than it was when I was wearing glasses. For the first time in over 60 years I can walk around without them - though I have to be very careful about judging distances on my left.
The clarity, the light and the colours I experience with my enhanced right eye are nothing short of remarkable.
Will update this in about 10 days
2 likes, 214 replies
sue13546 Siempre
Posted
hello thanks for posting look forward to seeing your progress. i totally understand about walking around without glasses...for me its been the first time in 50yrs. my cataracts were just extracted a month ago, so i'm still in the wow stage.
softwaredev Siempre
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I'm wondering if they may have corrected part of the astigmatism via incision, in addition to the part they correct via using a toric lens. The specs for the ZXT375 only shows it correcting 2.57D of cylinder at the corneal plane. Any residual astigmatism may interfere with vision at all distances, and account for your inability to read with that eye. Your high level of astigmatism does make good results more of a problem than for most people. Its possible if they corrected part of it via incision that your eye needs time to heal and reshape, and its also possible the toric lens may not be rotated correctly and they need to adjust it.
Its also possible the lens power was off a bit, there is more of a risk the lens power will be off in highly myopic people. If the lens power left you a bit hyperopic, that reduces your near vision and may account for your difficulty with reading. If that is the case, they could target the other eye to be a bit myopic, a bit of micro-monovision, to make up for it and give you better near.
If they managed to get the lens power right and rotate the lens correctly, most people should expect to be able to do some reading with the Symfony, though nothing is guaranteed, the studies merely report average results. Your case is atypical in terms of how large your refractive error was beforehand, increasing the risk they won't precisely correct your vision. In terms of being able to read, since they moderate links on this site, google "My experience implanting the Symfony lens this past year" for one surgeon's blog giving his experience (I figure its a bit more readable than studies using jargon most people don't know, though he does refer to one unit of measurement for font sizes people may not knwo). He notes: "All Symfony lens patients could see N8 type comfortably without glasses, which is this small, and 92% could see N6 comfortably without glasses, which is this small. ". N8 is considered newsprint size type, and most books tend to be a bit larger, and N6 I see labeled phonebook size print, if people can remember what that phonebooks were like :-).
If you google: "visual acuity" "font size"
you'll see a list of what visual acuity is required for different size fonts, and only 20/50 at near is required to read newsprint. Most people who get the Symfony don't need glasses, and those who do usually only require low add readers at times (though there is no harm in using readers to get crisper vision even if they aren't needed, to increase reading speed).
Studies show the average near vision at 40cm for a Symfony set to focus at distance is 20/40, and near vision at 50cm is on average 20/30. If you get one eye set in a little closer, some micro-monovision, then the average near vision improves. At my best near distance (where you hold the chart where its clearest) I tested 20/25, but the last test was at a fixed 40 cm and it didn't have a 20/25 line, so I tested 20/30 but saw some on the 20/20 line. That is the result with both eyes, one of my eyes was left a bit hyperopic but the 2nd eye makes up for it.
Siempre softwaredev
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softwaredev Siempre
Posted
They mentioned the myopia for your right eye, did they mention the residual astigmatism? If you are at -0.5D that should be enough to read with the Symfony (my better reading eye is -0.25D with -0.25D of cylinder, for a spherical equivalent about -0.375D, which gave me 20/25 at near by my 1 week postop, though it might take longer for others to neuroadapt), unless the eye is still healing or there is residual astigmatism, or there is some other eye problem that is reducing the potential for good vision in that eye.
I'm guessing the 7.5D for the lens may be the spherical power of the lens. I wasn't as myopic as you and one of my eyes got a 10D lens, and with IOLs the more myopic you were beforehand the lower the spherical power of the IOL, so that would seem possible. The puzzle is the astigmatism. I don't know if there might be a typo in your data somewhere since it doesn't add up if they didn't do an incision for the rest of the astigmatism.
If you google tecnis symfony, the manufacturer's web page should show up and on the clinical tab you'll see the specs for the lenses.
The ZXT375 is listed as correcting 3.75 D of cylinder at the IOL plane and 2.57 D at the corneal plane (the power of a lens depends on how far it is from the eye, which is why contact lens and glasses prescritions aren't exactly the same, the equivalent correction at the spectacle/glasses plane of that IOL would be even lower). Yet you listed your astigmatism in the right eye as being -6D. I don't know what plane that -6D is, if its the corneal plane, e.g. from a corneal scan, a contacts prescription, or the spectacle/glasses plane from a glasses prescription. However, regardless of what plane its from, its higher than the cylinder correction at any plane by the lens you mentioned.
softwaredev
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Oops, I've been mentioning my recent refraction results, actually the initial tests put that eye as being -0.5D and 0 astigmatism in refractions the first few months, which was what gave me the 20/25 near. A different doctor did this latest refraction, so I don't know if its a slight shift over 2 years, or if the shift is measurement differences, since its a small change, perhaps I was on the borderline before.
softwaredev
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sue13546 softwaredev
Posted
since i was having same issue as you with the 'oops' , i started to post my replys in wordpad and then cut and pasted to forum.
rgCalifornia softwaredev
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He notes: "All Symfony lens patients could see N8 type comfortably without glasses, which is this small, and 92% could see N6 comfortably without glasses, which is this small. ". N8 is considered newsprint size type, and most books tend to be a bit larger, and N6 I see labeled phonebook size print, if people can remember what that phonebooks were like :-).
Interesting that all of his Symfony patients could read newsprint comfortably without glasses. That was my main goal in choosing the Symfony: to be able to read newspapers and magazines, use my laptop, and see distance, without glasses. I can read a newspaper in strong sunlight, but I have to strain (it's not comfortable). I suspect I've ended up a wee bit overcorrected, which as you know is a greater risk with those of us with high degrees of myopia.
deborah83975 Siempre
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Siempre
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Given that I only have good vision in one eye, I have not been driving since the operation. At the moment I would find the halos around lights to be a problem when driving at night.
Tests were carried out on my right eye last week. The results were: refraction is -0.25 sphere with no astigmatism. I can see unaided 6/6 and 6/4.8 with a -0.25 sphere correction. I can read N6 unaided.
As to the absence of astigmatism in my right eye: while the prescription for my glasses had an astigmatism reading around -4 (L) to -6 (R), the readings at the cornea (from Pentacam measurement) was nearer to -3 and corrected by the Toric lens.
The plan now is to operate on the left eye using a ZXT450 lens with a spherical power of 6.5D (my right eye was 7.5D).
softwaredev Siempre
Posted
Sorry to hear about the intraocular pressure issue, but its good that your acuity seems to be good now and that you have some reading vision. In terms of the astigmatism, it sounds like they did a great job if they managed to get rid of all of it.
Since they did get rid of the astigmatism, the explanation is likely that preop part of the astigmatism was in the lens rather than on the cornea, lenticular astigmatism. Usually most astigmatism is on the cornea, but sometimes it can be on the lens.
In my case actually the cataract caused a few diopters worth of astigmatism to temporarily appear in the lens, but since such a shift is unusual I figured someone posting would have mentioned it, and usually there isn't that much pre-existing lenticular astigmatism.
Siempre
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The selection of the Symfony ZXT450 shows that the astigmatism in my left eye is slightly higher than in my right when measured at the cornea. This is the opposite way around to my prescription for glasses.
At this early stage I do not think the second Symfony lens has hugely benefitted my near vision, but that may change. Distance and mid distance vision appears to be excellent and I can use my laptop without reading glasses. Newsprint however is still difficult and I can see starbursts around streetlights - as with the right eye. One other consequence after each operation was that daylight can seem very bright for a few days. Fortunately perhaps we are not having much sun at the moment.
Overall (and given my glasses prescription above), I am very pleased with the results.
Post op check up will be in a few weeks and I will provide another update then.
Night-Hawk Siempre
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The Symfony ZXT450 (toric 3.08D cylinder corneal plane) IOL you got for your left eye must be a new model? I don't see it listed at the website with specs on the available Tecnics Symfony Toric IOLs, there they only list up to the model ZXT375.
Are there higher cylinder models for the Symfony Toric IOL available outside of the USA? I know there are higher cylinder models for the Tecnics Toric monofocal IOLs, up to model ZCT600 (4.11D cylinder corneal plane).
This is important for me since my eyes have high astigmatism, left=2.0D, right=2.75D (eyeglasses Rx) and might be higher than that at the cornea.
Siempre Night-Hawk
Posted
If you can find the Tecnis page for Tecnis Symfony IOL, under product overviews click on "NEW! TECNIS Symfony IOL". look under the SUPPORT tab, scroll down the page to the Toric extended range. There it lists models from ZXT100 to ZXT600 - including ZXT450.
My surgery took place in the UK.
Hope this helps.
Night-Hawk Siempre
Posted
So this does appear to indicate the Symfony Toric IOL is available at higher cylinders beyond the ZXT375 model only outside the USA. Maybe in the future the USA will approve the higher cylinder models as well, hopefully...