Phakic Intraocular Lense Implant, LASIK or Something Else?

If you are thinking about having Lasik, IntraLasik, PRK, LASEK, Epi-Lasik, RLE, or P-IOL eye surgery, this is the forum to research your concerns or ask your questions.

Phakic Intraocular Lense Implant, LASIK or Something Else?

Postby piblake » Fri Aug 18, 2006 9:53 pm

I'm struggling to decide between Phakic Intraocular Lense implants or LASIK. I've had consultations with two different doctors, and while both have told me that I'm a candidate for LASIK, one will only concede to performing the collamer lens implants as my prescription is up around -8.00 and he feels I will enjoy much better visual acuity with the implants. My cornea is somewhere in the 530 range and he believes a second adjustment may not be possible in order to retain the FDA-mandated 250.

I've read quite a bit on both procedures, and discounting the difference in price between the two, I'm most concerned about the lack of long-term information on the implants. I do; however, like the idea that it is reversible, does not permanently change my cornea, and allows me to make adjustments of several kinds down the road (whether LASIK, contacts, and who knows what else technology will bring in several years).

I understand that the FDA only approved the use of Verisyse lenses in December of 2005. Is this also the case for Visian? I'm not sure which my doctor uses, but I've read that the Verisyse, placed in front of the iris, can disrupt endothelial cells and that studies have shown a 1.8% decrease in endothelial cells per year and it is unknown if the loss will continue at such a rate in the future. What I don't know is what does it mean to one's vision if one continued to lose endothelial cells?

Can you provide other variables that I might consider when making my decision between procedures and doctors (I'm aware of the 50 questions)? Both have done many LASIKs, but the implants are so new that neither has done a lot. I know one has only completed 20 (10 people).

Complicating this whole matter is the fact that I am due to be laid off in about 6 weeks and would like to complete at least some of whatever procedure I choose so that I may claim it against my flexible spending which I maxed out this year in anticipation of getting LASIK surgery (didn't know about the possibility of implants when I went in in Dec. of 05).

Thank you in advance.




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Postby LasikExpert » Sat Aug 19, 2006 1:08 am

You have been doing your homework!

The endothelial cells on the back side of the cornea transfer nutrients to the cornea. If there are too few cells, the cornea "starves" to death. That is an oversimplification, but the result can be catastrophic. Endothelial cells do not quickly regenerate and loss is considered permanent. Endothelial transplant is expensive, invasive, and although relatively successful, not something you want to encounter due to an elective surgery.

Doing a rough calculation it would appear that LASIK would be possible with your corneal thickness, however wavefront-guided ablation requires more tissue and larger ablation zones to accommodate the size of your pupil also requires more tissue per diopter of change. This may be why your doctors are so concerned about corneal thickness. You should investigate IntraLasik due to its superior accuracy of Lasik flap thickness and ability to create a thinner flap.

The Visian ICL was approved after the Verisyse, but it had actually gone through the process before the Verisyse. The manufacturer had a problem with a manufacturing plant unrelated to the Visian ICL and the FDA would not approve anything until that was resolved. Be sure to read our article about Visian ICL and Verisyse.

I doubt I will be of much use in regard to making a decision. I have never and would never tell someone to have refractive surgery. That is a decision only you and your doctor can make. Your risk of problems is elevated with all forms of refractive surgery because of your relatively high refractive error, but you are not so high as to be out of the realm of possibility.

You have a difficult decision to make, but you appear to be going at it the right way by becoming well informed.
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More questions on P-IOLs and laser surgery

Postby piblake » Sat Aug 19, 2006 9:06 pm

Thank you so much for your reply. I've re-read some of the information on the site (which I think is so very useful) and have a few more questions.

1) The site mentions that Verisyse and Visian have distinct advantages and disadvantages, but I wasn't able to find what they are. I read that Versisyse disrupts the endothelials cells on the back of the cornea--a distinct disadvantage, but that is all I was able to gather. Can you elaborate on the other advantages and disadvantages of both?

2) In your reply you are clear that the loss of endothelials cells is not good at all. If someone had P-IOL surgery with Verisyse, is it possible to determine when the lens should be removed based on the amount of endothelial loss. At what point should it be removed?

3) For either type of P-IOL surgery, you mention that the depth of the anterior chamber is important. Can you tell me what the minimum depth should be, please?

4) Are the doctors approved by your organization and listed on this site, also approved for Verisyse or Visian? The product is so new that I'm not sure how to best evaluate the doctors I do know are doing it in my area (metropolitan Washington DC). Should I rely on how many cataracts surgery they've done since none of the three have completed a lot of P-IOLs?

5) Am I more likely to need reading glasses sooner if I, as a 42-year-old, high myopic at -8.00, choose to have one of the laser-type surgeries instead of P-IOL surgery? In other words, do the laser surgeries somehow cause you to lean closer to requiring glasses sooner while the P-IOL does not because the crystalline lens remains undisturbed?

6) All else remaining the same, can I still be a candidate for laser-surgery if I chose to to P-IOL and then for some reason need to have the lenses removed?

Thank you again for all your assistance. I've found your site most helpful.
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Re: More questions on P-IOLs and laser surgery

Postby LasikExpert » Sun Aug 20, 2006 12:31 am

piblake wrote:1) The site mentions that Verisyse and Visian have distinct advantages and disadvantages, but I wasn't able to find what they are. I read that Versisyse disrupts the endothelials cells on the back of the cornea--a distinct disadvantage, but that is all I was able to gather. Can you elaborate on the other advantages and disadvantages of both?


The relative advantage or disadvantage depends greatly on the physiology of the individual's eye.

Because the Verisyse is in front of the iris, it is easier to place. Because the area between the front of the iris and the back of the cornea is limited, there may not be enough room for the thickness of the optics. A smaller optic will reduce thickness, but a smaller optic may cause problems if the pupil is large. Vigorous rubbing of the eyes can cause trauma with the Verisyse. The Verisyse is visible to others, but they need to look pretty close. Because the Verisyse is attached to the iris, a specific angle is possible. A toric Verisyse (available outside the US as the Artisan) can correct astigmatism as well as myopia. Because the Verisyse is in front of the iris, it is relatively less difficult to remove.

Because the Visian is behind the iris it is very close to the natural lens. If the natural lens vaults forward and touches the Visian during accommodation (focusing), the trauma can cause a cataract. Placing a lens in this small space takes a lot of surgical skill. If the natural lens receives too much trauma during surgery, a cataract can form. The optic of the Visian has the same limitation as the Verisyse. Higher power is thicker. Smaller optic is thinner. Pupil size becomes involved. Because the Visian is behind the iris, it is relatively more difficult to remove.

With both, if the pupil becomes larger than the optics, glare, halos, starbursts, and poor vision can result.


piblake wrote:2) In your reply you are clear that the loss of endothelials cells is not good at all. If someone had P-IOL surgery with Verisyse, is it possible to determine when the lens should be removed based on the amount of endothelial loss. At what point should it be removed?.


This issue is a part of the FDA labeling and a concern we raised to the FDA. A formula was created to determine current cell count, probable loss at surgery, probable loss over time, and the minimum cell count necessary for eventual cataract surgery. Ongoing cell count can determine when the P-IOL must be removed. Unfortunately doctors can simply ignore this fact. Ask your Verisyse doctor if s/he will do an endothelial cell count every year to verify the health of your cornea and if that service is included in the price of the P-IOL.

piblake wrote:3) For either type of P-IOL surgery, you mention that the depth of the anterior chamber is important. Can you tell me what the minimum depth should be, please?.


The number is a variable depending upon the thickness of the lens to correct the refractive error. For the Verisyse, the distance from iris to back of cornea needs to be accurately measured. For the Visian the distance from the natural lens to the iris needs to be measured. Good technology exists to perform these measurements, but not every surgeon has this technology.

piblake wrote:4) Are the doctors approved by your organization and listed on this site, also approved for Verisyse or Visian?


We do not evaluate a specific procedure. We evaluate all refractive surgery procedures provided within a specific group of consecutive patients. If P-IOLs are in that group they are counted against the national norm, but P-IOLs may not be included. Our evaluation is refractive surgery as a class, not specific procedures.

piblake wrote:The product is so new that I'm not sure how to best evaluate the doctors I do know are doing it in my area (metropolitan Washington DC). Should I rely on how many cataracts surgery they've done since none of the three have completed a lot of P-IOLs?.


A history of successful cataract surgery shows skills within the eye. That is a good indication of ability, but cataract surgery is not the same as implanting a P-IOL. Wait until the doctor has completed enough of the P-IOL you are considering with patients that have your chamber depth, pupil size, and refractive error. In other words, the doctor needs to have enough practical knowledge of exactly what you would be receiving. Similar surgeries are valuable, but are not the same.

piblake wrote:5) Am I more likely to need reading glasses sooner if I, as a 42-year-old, high myopic at -8.00, choose to have one of the laser-type surgeries instead of P-IOL surgery? In other words, do the laser surgeries somehow cause you to lean closer to requiring glasses sooner while the P-IOL does not because the crystalline lens remains undisturbed?.


Refractive correction is almost always the same no matter what the method used. If you are corrected with Lasik. Epi-Lasik, P-IOL, or contact lenses your presbyopia will be essentially the same. The exception would be Refractive Lens Exchange (RLE), which would remove the natural lens and eliminate all natural accommodation, and spectacles, which provide a small mechanical advantage for near vision AND you can take them off to see things near.

piblake wrote:6) All else remaining the same, can I still be a candidate for laser-surgery if I chose to to P-IOL and then for some reason need to have the lenses removed?.

Assuming that the health of the cornea is not changed (which is probable), cornea based surgery would be the same after having P-IOLs implanted and then explanted.

piblake wrote:Thank you again for all your assistance. I've found your site most helpful.


I am glad to be of assistance, but you are the one who has to make the hard decisions.
Glenn Hagele
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Postby maxxed » Tue Sep 19, 2006 2:32 am

I was a -10D myope and have the Verisyse lens implanted in both eyes, and am very happy with the result.

I like the fact that the procedure didn't remove any corneal tissue and the Verisyse lens isn't known to cause cataracts.

Based on my research, I think the endothelial loss (first reported in Europe) was from studies conducted before modern viscolastics were available. Intuitively, there is no reason the lens should cause endothelial loss after implantation unless it contacts the cornea, which should never happen unless you vigorously rub your eyes as Glenn mentioned.

One disadvantage for me was the temporary astigmatism created by the relatively large incision. This went away after three months or so after the stitches were removed.
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Postby LasikExpert » Tue Sep 19, 2006 2:48 am

A person with 10.00 diopters of myopia (nearsighted, shortsighted) vision should investigate phakic intraocular lenses (P-IOL). The cornea-based surgeries like Lasik, PRK, etc. don't do as well with high refractive error. If the patient is highly myopic and fully presbyopic (bifocals, reading glasses), Refractive Lens Exchange (RLE) should be investigated too.

A viscolastic is a semi-solid clear gel injected inside the eye during surgery to protect the interior surfaces, including the cornea. The FDA clinical trials were only a few years ago and the viscolastics used are pretty much the same as today. After some P-IOLs the endothelium does diminish with time, but the amount of time that passes before there is need for concern may be more than enough. Each patient needs to be independently evaluated.
Glenn Hagele
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USAEyes

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I am not a doctor.
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