Looking for recommendations regarding monovision and Apthera ic-8

Thanks for your reply. I am still not sure if two monofocals is the best plan.

With a monofocal at -1.5 D, how close can reading be? By the numbers monofocal only has a depth of field of 0.75 D. So that has me most worried. The range I least care about is far.

As for the astigmatism. Yes I wouldn't go with IC-8 until they have a toric version. I have enough irregular astigmatism that regardless of which toric is used some amount of laser surgery will be needed to trim it for monofocal or trifocal. Currently I have 6 images in my right eye and 2 in left without glasses. With glasses my right eye has at best 2 images. I cant read at all if the text is sideways. It is only with the aid of my left that my right appeared to be normal. A toric IC-8 would be the only one that could prevent that as it corrects 1.5 D irregular.

Is there some reason to avoid a trifocal for the dominate right eye? Though technically it was once 20/20 because I could read double images, I haven't been correctable to normal since youth. A trifocal would seem like an improvement. Are those who are unsatisfied with multifocal, people who had good vision and feel it is worse? I was willing to take more risk on right because it has been poor.

On a spherical equivalent basis (sphere + 50% of cylinder) my distance eye is -0.40 D. It started at -0.25 D but astigmatism went up a notch, but still have 20/20 in that eye. My near eye is at -1.60 D. With my distance eye I can see my car dash quite easily and can read a computer monitor down to about 18-20". My near eye is useful for 65" HDTV viewing at 10" but is starting to soften up a bit compared to my distance eye. I can see a computer monitor down to 8-10". But everyone will differ a little in that respect. In any case I have a substantial overlap in the eyes with full binocular vision in that range. My distance eye is an AcrySof IQ aspheric monofocal, and my near eye has the newer Clareon aspheric. Optically they are essentially identical monofocals with -0.20 um aspheric correction. Some get the idea that monofocals drop off a cliff when you get away from their set distance. Actually they have quite a wide range which can be significantly enhanced with mini-monovision.

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Be careful with the irregular astigmatism. I have that in my near eye and it gives me a drop shadow on letters. I can still read J1 in sunlight but it could be better. I decided against a toric because my surgeon was not sure it would help, and suggested Lasik to touch it up. Lasik has turned out to be a dead end. If they correct the irregular astigmatism I will lose much of my reading vision (it measures -0.75 cylinder). And I have found out that it is very difficult to increase myopia sphere with Lasik. So, if you are counting on Lasik make sure the correction will be to reduce myopia, not increase it.

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If you do some searching around this site you will find there are issues with the latest trifocal IOLs like the J&J Synergy, and the Alcon PanOptix. They can give significant optical side effects to the point some get them removed. I have a good friend that has the PanOptix and still needs +1.75 readers to read, even in good light.

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The big advantage of monofocals is that they have the lowest risk of optical side effects, and if the power is off, they are easily correctable with an eyeglass lens. The optical tricks that the Synergy, PanOptix, and others are not easily correctable with eyeglasses.

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These trifocal lenses are really only recommended for those that have "perfect" eyes. The enVista lens on the other hand is much more tolerant of less than perfect eyes. It may be harder trying to find a surgeon that uses them though.

Thanks for the detailed reply. The published curves on the vision tests imply that monofocals fall off fairly hard, but I am glad that you are getting good mileage out if it.

I was aware of the visual issues with trifocal. They are comparable with my current vision in the right. Residual astigmatism even with glasses is strong enough that stop lights at a distance look like the number 8 and I already see haloes and streaks at night. It looks just like the pictures of what a trifocal does at night. Which left me confused as that is what I always see in the right. Though perhaps the are worse with trifocal.

It may be because the location of the cataract. I have often wondered if I can actually see it. When using a microscope there has always been a wormlike thing in my vision. I assumed it was on the back, but now that two doctors said I have a congenital cataract I have to wonder.

I have read that lasik can only correct some problems. Sorry to hear that yours wasn't correctable. The doctor said there was a procedure he could do as while operating to deal with the iregular astigmatism assuming the toric was in place. It involved using a laser at the edge rather than center to flatten. Though I did not catch the name. He was very confident that he could achieve acceptable vision as he had done many similar corrections. The most common being using two bifocal to give mixed ranges.

Regarding the light loss on the IC-8, all of the studies I found indicate the loss of night vision is less than expected. It is cutting light to 25%, but it is also more transparent than a natural lens by about 20%. So you would expect it to be the same as 30% sun glasses. But the human eye has many orders on magnitude range so the loss is really just coming out of the rod range. So unless it is dim enough you cant see color, most people cant see the difference.

On important consideration for anyone considering the IC-8, is pupil size. The rear aperature works with the natural iris. Those with large pupils (>4mm) in studies didn't get the expected depth improvement. Those with smallest pupils (<2.5mm) saw the best range. Still larger than monofocal, but not the range stated in the company literature.

I do agree with you that having one eye completely correctable with glasses. That is why I would not consider trifocal in two eyes.

I have year to think it over, so thank you for the input. I will see about finding some studies to see the outcomes of each of the lens mentioned.

Have a look at these figures, and in particular Figure 1 & 2. Figure 1 shows the visual acuity of a standard monofocal set for distance, as well as the same lens set for various offsets of 1.0, 1.5, and 2.0 D. 20/32 is considered to be the limit of normal useful vision for each lens configuration. So, if you draw a horizontal line at that level you can see what distances each lens configuration is useful over.

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https://www.semanticscholar.org/paper/Optimal-amount-of-anisometropia-for-pseudophakic-Hayashi-Yoshida/dd8837a9151a536759f195a18d4fa94a0fbf0f90

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Figure 2 shows the combination of a lens in one eye set for distance plus the various offsets in the other eye. You can click on each figure and the Expand link for more detail, but unfortunately the complete article is no longer on line that I can find. The objective of the study was to find the optimal offset for monovison. The conclusion was the -1.5 D offset was optimum. The -1.0 D comes up a little short for reading vision, and -2.0 has a significant drop in the 0.7 meter range. The 1.5 D offset provides a significant overlap for the two eyes as well.

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As you can see when you look at the complete range two correctly targeted monofocals do quite well.

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On the astigmatism and impact on vision I am not sure I would draw any strong conclusions when you are looking through cataracts in your lenses. Your best indication of your outcome will be with the measurements taken by the IOLMaster and Pentacam. They should be able to predict your residual astigmatism with a non toric and toric lens. Typically (but not always) astigmatism goes down significantly when the lens with the cataract is removed. My cylinder went from -2.75 down to -0.75 in one eye with a non toric lens. The other eye with a non toric also went from -1.25 D cylinder down to -0.75 D. It had a much less significant cataract at the time of surgery compared to the other eye.

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Yes, Lasik makes corrections for myopia with radial cuts in the cornea, while circumferential cuts are made further out for reducing hyperopia. The issues are that circumferential cuts have a less predictable outcome, and they typically are not stable over time, and may require multiple treatments. Limbal relaxing incisions (LRI) made during surgery according to my surgeon are not very predictable either.

Thanks so much for the reference. It should be available on my work library. Helps to work at a large government research institution.

I don't anticipate my cylinder changing much. My lens for the both eyes has been in the -3 range since high school. The cataract is just pushing the number up further into the -4 range. Thus bringing me to the edge of my tolerance for glasses. Every time they have to up the base curve to increase the power I have to live in a fish bowl world with screaming migraines. After the last round I decided it was time to find other options.

When you get your eyes measured you should ask for the IOL Calculation sheet. And if the clinic is cooperative you should also ask for a screen shot of the cornea topography. Those two items will give you a good idea where you stand. On the topography shot look for whether or not the image is symmetrical like an hour glass or bowtie. That indicates regular astigmatism.

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If you google this you should be able to find a document which is helpful in reading the IOL Calculation sheet.

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Zeiss IOLMaster 700 Quick Guide Printing Functions EN PDF

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Page 5 gives an example of a calculation for a non toric, and page 7 shows a toric calculation.

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When you consider your astigmatism as measured for an eyeglass prescription consider that the astigmatism likely comes from three sources. One is the topography of the cornea. The other two are the shape of the natural lens, and the last is the distortion caused by the cataract growing inside the lens. Of course with cataract surgery the total lens is removed and replaced with an artificial lens, so the astigmatism in the lens and the distortion due to the cataract is removed. That is why astigmatism is likely to go down with cataract surgery. You only really know what the residual astigmatism is likely to be after the measurements are taken and the IOL Calculation sheet produced. There will also be an estimate from the Pentacam topography measurement.

Mine is a bow tie with a curve such that it looks between a backwards S and a ?. Glasses fix the primary axis, but when the pupils are dilated the axis rotates. Wearing my glasses crooked helps at night.

I just wish I could have PRK or lasik now to remove the cortical astigmatism first , wait a few years for my eyes to heal then get the surgery for cataracts later. At -3.5 D even the slightest angle miss adjustment ruins my vision. If I didn't have to worry about the angle of the IOL, this would be much easier.

One option you may want to consider is topography guided Lasik, sometimes called Custom Lasik. From my research and consult with two Lasik clinics it should be quite possible (but expensive) to correct your astigmatism fully even if it is irregular. I would only have them correct the astigmatism to minimize the impact on the cornea, and not address the sphere. Leave that for the IOL to correct. The plan would be to get the astigmatism Lasik done now and then do the cataract surgery after the eye recovers from the Lasik. It may be possible to cut that time to even less. Providing the Lasik is accurate you should not need a toric IOL. You will want to be sure your eyes are measured for IOLs before the Lasik so you have a reference as to what that has done. Prior Lasik does complicated IOL power calculation some.

Thanks a lot. I think my best option is to find a surgeon willing to compose a long term plan. My original goal was to get lasik or prk for the sole purpose or reducing my astigmatism so that I can function with glasses until I retire. The cataract in one eye is just a complicating factor. But it may be 10 years before it develops further given that it appears to be congenital.

If I set my goal on getting refractive surgery to get my eyes to -3D with 0 cortical cylinder, then I can last until my right cataract gets bad enough to warrant surgery or the left eye develops cataract (currently at the far edge). There may be much better IOL at that time and I will have both better vision and better options than worrying if the toric is correct and struggling to correct if it is not.

As many people on this forum have stated natural lens are best until they are not usable. So I should try to get 5 years.

Yes, you need a long term plan. I would not count on the cataract issue to be slow developing. You are younger, so that is a sign they may be fast to develop. Normally cataract do not become an issue until you are 70 or so. The other sign of faster development is your eyeglass prescription changing fairly quickly. For some the limit of tolerance for a cataract is the frustration of having to get new eyeglasses lenses every few months instead of every couple of years.

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I think your best solution, but only if it is possible is to get custom Lasik or PRK to correct the astimatism only and leave the cylinder untouched to minimize the amount of Lasik done to the eye. You will likely have to do a fair amount of searching to find a Lasik specialist that will be capable of doing that, and has the sophisticated equipment to do the custom, or wavefront guided, or topography guided type of Lasik. Remember that you can only deal with the cornea any you only want to "fix" the astigmatism in the cornea, and ignore the astigmatism in the lens. If you try to adjust for the astigmatism in the lens then when the lens is removed, that correction will be still built into the cornea and you will have astigmatism again. So it would be very unadvisable to correct for the lens astimatism.

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Remember that most Lasik specialists are really only interested in dealing with younger people that want to ditch their glasses. They compete on lower prices, and they just put in generic sphere and cylinder corrections like eyeglasses. Best to avoid those. Here is what the last specialist I went to says about Custom lasik that they do.

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"About Custom Laser Eye Surgery

LASIK, or laser-assisted in situ keratomileusis, is a quick, painless form of laser eye surgery designed to correct myopia, hyperopia and / or astigmatism so you can greatly reduce or completely eliminate your daily dependence on prescription glasses or contact lenses.

Your eye shape and corneal topography are as unique as a fingerprint. Before starting the laser vision correction procedure, Custom Femto LASIK WaveFront-driven imaging technology is used to generate a distinct map of your eye’s optical system, including its unique refractive error. This advanced diagnostic technology identifies the slightest eye abnormalities with far greater precision than ever before possible, including nearly imperceptible deviations known as “higher-order aberrations.” The Custom Femto LASIK WaveFront-guided treatment includes a distinct optical-correction schematic uniquely tailored for each individual eye. This data is used to customize your surgical treatment protocol, and directs the SCHWIND AMARIS® 750S excimer laser that is used to reshape the curvature of your cornea during laser eye surgery.

Once your optical system has been mapped, an advanced femtosecond laser technology, called IntraLase, is used to create a corneal flap. The corneal flap is lifted to access the underlying corneal tissue. Then, using the SCHWIND AMARIS® 750S excimer laser, the curvature of the cornea is reshaped to correct your nearsightedness, farsightedness or astigmatism.

The SCHWIND AMARIS® 750S excimer laser system is the most advanced laser platform currently available and, thanks to its revolutionary iris registration technology, is able to align treatment automatically, with the highest degree of precision, regardless of whether the patient’s pupil has shifted positions between the moment the eye was first measured and the time of treatment. Iris registration technology also ensures the greatest degree of personalized treatment, as no two eyes are the same. Once the laser eye surgeon is satisfied with the newly contoured cornea, he carefully places the flap back in its original position, where it re-seals itself to the eye, without the need for sutures.

Patients usually notice an improvement in their vision within 24 to 48 hours after surgery, and are able to return to work or their normal activities at this time. Often, patients no longer need to rely on prescription eyewear to see clearly, and many achieve 20/20 vision — or better — after laser eye surgery."

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Although this only talks about Lasik, I believe the same can be done with PRK. The only differnce is that PRK does not use the flap, and the outer layer of the cornea is removed. Athletes often use PRK because it is more durable in contact sports. Although we never got to the point of talking prices, I would expect it may be in the order of $3,000 per eye.

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Also ideally you want a Laser surgeon that also does cataract surgery and approaches the whole thing as a two stage project. Correct astigmatism in the cornea only first, and then does the cataract surgery to correct the sphere and of course get rid of the cataracts in the lenses as the second phase.

There was been no detected change in the cataract from last year for the central one. Given that I have always had poor vision both doctors felt is was congenital, but if it is not that just pushes up my time line. If it is not congenital then it should develop quickly being either genetic or environmental. (I work with radiation sources but the total beta dose to eyes should have well under the level that would cause cataracts.)

I only recall once when I was very young a doctor mentioned that there was a defect in my right eye. But it was so long ago no one remembers the specifics.

My left eye is currently clear with very small age related cataracts at the edge. My right has similar very small cataracts at the edges in addition to the central one. Based on the edge ones all doctors I have consulted told me that it would be years for the edge ones to cause noticeable vision loss.

Did some additional research. It seems PRK before cataract surgery is not an option. The reason for this is that the formulas for computing the proper correction are based on the edge of the eye rather than the center. There have been efforts to devise formulas that work for for post PRK/lasik but the results in correction are all over the map so not something reliable. Some people get great vision while others end up very near or very far sighted depending on how far the formula/measurements miss.

I also found that my only options are toric monifocal or seeing if i can get post op refractive correction with a nontoric.

Here are the reasons for this: Almost all EDoF lenses (non accomidating) use tricks with putting different corrective ranges at different distances around center of the lens. The outcomes depend a lot on pupil size. Those with large pupil sizes will get the desired correction. But those with small pupils will generally only get a fraction of the desired light at the target distance. There differences in the order of these zones. For example, vivity is near distance in the center. Thus in conditions where the pupil is constricted too much there is no far vision. The problem is further complicated by the shape of the eye and age. As people age their pupil shrinks. Near and far sightedness also change the expected pupil size. Thus a trifocal may work in a young miopic patient in large pupils, but fail entirely in someone who is older, far sighted, or a person with small pupils. And as we all age that means a trifocal in a 45 year old may fail later as they age. This alone should steer people away from most EDoF lenses. The amount of digging that was required to find this means a lot of people are going be misinformed.

The IC-8 is the only one that does not play these games. Though this comes at a cost of 1.3 mm small pin hole that operates when the eye is in normal lighting. You will notice that the mask only covers the inner 3.5 mm potion of the 6 mm lens. When the eye dilates beyond the edge of the mask then further light comes in from the edge which limits the night vision lose with corresponding loss in depth of field. A youtube found with search terms "apthera ic-8 bilateral asia" includes plots show the loss of contrast in bilateral implantation is small meaning night vision fears seem overblown.

The FDA recommendations regarding IC-8 seem very conservative and don't have much support in literature that I was able to locate.

Based on my reading I would consider the IC-8 to be viewed as being the same as a monofocal with the benefit of twice the depth of field. If further solves problems with mild astigmatism and irregular astigmatism as well as improved vision with post refractive surgery eyes. The only significant downside being it currently is not usable with moderate to severe astigmatism.

There visual artifacts are also similar to monofocal. These will occur even without diffractive rings at night because the replacement lens is smaller than the natural lens thus in full dilated conditions the edges will be illuminated.

Pupil size also plays a role in monofocals. older patients with small pupils or who were far sighted (who naturally have smaller pupils) prior to implantation will have larger depths of field. The same holds true with the IC-8 though as it base depth of field is larger it would be of less concern. Meaning anyone considering monovision needs to consider if their pupil size will give them the depth of field.

Given no differences in night vision and the benefit of twice the overlap range for binocular vision, there should be no reason to avoid IC-8 especially for monovision patients. It is simply a superior monofocal for many patients.

Please note that I am not a medical doctor and am just sharing research to help others be informed.

Sadly unless there is a solution for moderate astigmatism I would be stuck with toric monofocal. My pupils are too large for good depth of field with a monofocal, but not regular enough that a EDoF will work. And I am too astigmatic for IC-8. Meaning all options are not great.

I will continue to explore. My revised plan is to not get my left eye worked on but use a contact and get some type of monofocal in my right. My right eye cataract is likely to worsen, but there is no reason to risk the left.

Karlo - Why not get the IC-8 for the depth of focus and wear glasses for the astigmatism?

Well the astigmatism was the original reason that I wanted refractive surgery. With my current glasses I can only read a computer screen with a very limited field of view. It was fine when both eyes could see the screen, but which the changes that started 5 years ago it is making programming painfully slow. One would think that with a giant screen and large text with enough distance I could make it work, but I am finding it a struggle due to chromatic aberration with different color letters standing at different heights unless I look dead on. I would gladly take my -4.5 D myopia if I could see less than 6 images when I try to read without glasses; hence the astigmatism needs to go. As a person who spends twelve hours a week reading (not counting the computer time for work), loss of reading vision is the worst.

There is currently no distance (with or without glasses) that I can read small print (it always required binocular vision to read fine print) and no correction currently gives less than two images in my right eye hence my preexisting monovision. I could get a special pair of lens just for reading, but already have a pair for computer and driving about a 0.5 diopter apart. I have yet to be able to tolerate bifocal or progressives. Due to disabling migraines, I try to limit the range of changes in glasses that I wear each day. Reading for ten hours seems to completely prohibit full distance correcting that day. A few hours outside with full distance glasses and I can forget about reading at all.

I am unsure if I could find a doctor willing to place an IC-8 in my dominate eye especially with request for PRK follow up. The IC-8 would be the very best option for me if it were toric. At -1D I would still have enough distance to pass a drivers exam and be able to read near with little effort. Minor plus up or down won't set of a migraine which leaves me blind for 8 hours. (A fat lot of good glasses do when all you can see is green and moving. If I am really unlucky I get a vertigo migraine and get 8 hours on the tea cup ride.) And it would give me binocular vision at computer screen range which would remove the current illusion that the screen is warped which is the effect of my strong dominate right eye trying to fight my much better left reading eye for control after driving. The eye patch solution helps but I don't like sitting there looking like a pirate.

I did find a paper where they used IC-8 in high astigmatism eyes, but their solution was to use two IOL. The IC-8 in front and then a toric correction in back placed after the first had healed. That seems even more scary than the PRK.

Karlo - Have you tried scleral contacts? I have keratoconus with -8.25 cyl in my right spectacle lens prescription. The clarity of vision with scleral contacts is amazing. I only got the lenses to be able to experiment with mini-monovision and after the experiments I put them away in a drawer, because glasses correction is good enough for me and I don't want the bother of putting in and taking out contacts on a daily basis. Normal contact lenses don't work for me at all.

(For those who don't know, scleral contacts are hard contacts that are bigger and more convex than normal contacts. Being bigger in diameter, they rest on the slera --whites -- of the eyes. Being more convex -- i.e. more deep-dish-shaped -- they do not touch the more sensitive iris and pupil areas, (which has the neat side benefit of making them more comfortable). Instead resting on the center of the eye, they arch over that area. creating a space between the lens and the iris/pupil that you fill with saline solution. Since the saline has about the same index of refraction as the cornea, this completely removes the shape of the cornea from your vision dynamics. The shape of the contacts becomes the only relevant refractive surface at the corneal/contact lens plane. Corneal astigmatism is automatically rendered irrelevant without any astigmatism correction prescription (no cylinder). Sclerals give perfect and complete correction of corneal astigmatism when you are wearing them. If you also have lenticular astigmatism, then there you need toric scleral contacts just for the lenticular component.

Thank I will have to check them out. I have always used glasses so this is very helpful.