NAc eyedrops revisited

[Jorginho]

I've had retinal detachment and subsequent vitrectomy with lasersurgery. It is has been only 2,5 weeks ago and my Belgian doc says I had a "mega-tear"...She also lasered the other eye because it had two small weak spot.
I am 43 and she assures me I will have a cataract soon. Now I have come across several confilcting data on this. Some data says that if you are under the age of 50, the chance developing this is small. Other studies says it is irrelevant. So what is it now?

Now, I would like to keep my own lens as she also told me that this cataract surgery is not your standard version, as without a vitreous gel, things become more complicated...hmmm....Oke. So I searched for various options. Of course I came across lots of studies and remarks on various anti-oxidant eyedrops. I find it intruiging how extremes can say very certain things on this while in my view it is very uncertain. We have a Russian researcher who has done all research, also sells NAC (N acetyl carnosine) who has come up wtih excellent results. But when I read the placebo controlled randomised research I find it, well, unconventional. You really have to look well to come up with some usefull statistics if you can find it at all. Others dismiss it as snake oil...Well, if so, why does the University of Missouri (lead by Nuran Ercal) start a research of NAC-amide (NACA, the amide form penetrates the cellmambrnaes better)? And the researchers note that they do this research based on results with...NAC...They say NACA will ""improve on" NAC. HEnce, NAC does something right...And initial research by them showed that NACA prevented cataract formation.

I also contacted a researcher who has done some clinical trials with Oclumed, which is similar to thos NAC eyedrops. He explicitly told me he had two patients using them after the same surgery that I have had and after 18 months they show no signs of cataract. He says he has lots more with various succes. Some clearly improve, others don't and to him it seems promising but not conclusive. He says that it is irrelevant of which drops are used, they all have NAC in them.

Even recent studies on rats with similar if not identical eyedrops have come up with conflicitng data. One showed a delay versus controls, but after 4-6 weks the difference became insignificant. I noted that the dose used was 1/100 to 1/20 of the usal amount of NAC in eyedrops (0,0o1 to 0,05%).
Another study showed NAC 1% eyedrops clearly delaying the formation of cataracts for a long time, the difference between untreated eyes was significant and only became bigger. These two studies were done by Chinese.
I also found a study on rats deficient in Glutathione (hence developing cataract soon after birth) by some researchers from Houston with the same results: rats treated with NAC did not develop cataract over 11 weeks whereas untreated rats (or mice) developped dense opacities in a matter 3 weeks, becoming calcified etc between 6-11 weeks. How the NAC was administred was unclear though.

So.....this is not a question it seems but more a remark from me about these eyedrops. I think people categorically deny any possible relief are too negative as there is evidence that shows it is not only promising but that NAC is taken seriously by scientists. Otoh: those claiming that they work are also wrong because of the same conflicting data and the lack of good, double blind research on humans (although there is one study...as mentioned).

I have told my ophthalmologist that I have ordered these eyedrops, knowing they might not help. Here response was pretty negative. As I expected, as she assured me that lasertreatment for floaters was a 100% guarantee for retinal tears....But these are my eyes, not hers. I hope I will keep youi posted on this...

[JohnHaganMD]

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[James_P_Kelly]

It appears from this research that vitrectomies or vitrious separartion both expose the lens to deleterious levels of oxygen, hence increasing likelihood of cataract formation.
http://news.wustl.edu/news/Pages/4986.aspx

[JohnHaganMD]

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[hatailor]

There is by now more science on the rationale for the effectiveness of preparations that raise glutathione levels in the eye.  The question is how to deliver it effectively.  In the US there are compounding pharmacies, elsewhere there are only a few preparations.

The lens replacement business is huge, and it's sufficient reason to cast doubt on the drops and not to fund such research. Unfortunately patients must rely on small no-control trials and 'testimonials.'  And they must have a good amount of money to use compounding pharmacies.

[John C Hagan III, MD, FACS, FAAO]

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[Jorginho]

I understand that very well, I looked at my message and it was quite lengthy actually...May be because English is not my native tongue.

I said that I did find positive results.

1) in Nature, 2002 study finding moderate results and zero complications (14 month follow up). I also found a note of one of the reviewers who said the technique, number of session, laser used and number of shoots were all below par. Their advice was to FIRST use laser vitreolysis and than PPV. 2 of the patients who had a PPV after unsuccesfull LV developped a retinal detachment and the other a lens opacity (I guess a cataract).

2) A second study in the British Journal for Optm., 1993, used the laser on 15 patients with no ill effects. They also noted that the more experienced they became during the study, the better the results reaching 100% (!).

This is not about arguiing for the sake of the argument, I do understand that this forum is meant to inform readers. My information can be readily found on the net and, in this case, does not support your view (and info) here that LV is somehow unsafe, unproven and risky.

Finally a restate that I have been trying to find people who had ill effects after a LV. Again, it is very easy to find people with all sorts of problems with surgery or druguse, who are very negative about the outcome. However, on the main floaterforum it was noted that zero member who had LV had any complications. Not one. Only a Dutch LV specialist noted that 0.16% number and Dr Johnson noted that he made some errors when he started the treatment, because he was too eager to hunt some floaters down. That has little to do with the surgery but everything with the surgeon. A surgeon can do harm in virtually any operation if he pushes things too far...

Note that LV is not for me, I have no floaters in one eye and a very small translucent one in the other.

Again, thanks for your time and information.

[John C Hagan III, MD, FACS, FAAO]

I have not the time nor inclination to debate or argue in this forum. It is time consuming and all of usY serve without pay Pro Bono.  We all have busy practices and other commitments.

If you have not come up with any studies on the ineffectiveness of laser RX you have not done a thorough research of the world's literature. Again I will not do it for you.

I understand how much floaters bother people. If you will go to my blog I posted two studies on subjective quantitation of impaired quality of life due to floaters.

That is all I have to say. Best of luck to you.

JHaganMD, FACS, FAAO
Editor, Missouri Medicine medical journal

[Jorginho]

Hej John,

Thanks for you response. In general I do understand where you are coming from. As a sidenote I have been active in the field of science, just same very different field. Where possible I am all into statistical significance, N numbers that are high enough etc.

1: that was my thought too. The impression of a difference below or above 50 was based on subjective reports (the impression of ophthtalmologists) and the second figure (i.e.: "it doesn't matter all that much") was based on research.

2. That is reassuring, both my opthtmatologists had another opinion. I am also "studying" lens choices, crystallens seems the best current option.
In NL, this all does not cost me a thing (well, I pay some for the insurrance).

3.  I have not come across any scientific research showing that laser treatment for floaters is dangerous, ineffective or harmfull. Do you have any data on that? The research I do have on it showed a score of 0,16% for serious complications. And effectivily was scored, on a 1-10 scale, with an average improvement of 6 points. I also have not found any post on fora where lasertreartment lead to permanent damage to the eye, bar 1 or 2 cases. If I do that with medication or any other procedure, these negative reports are very easy to find...Now I know that lasertreatment itself is not done very often, so I understand this tosome extend. However: I do found a lot of positive results.
So what is the alternative for those troubled by floaters? A FOV. This alternative itself is certainly not without its risks. RD is one and I have come across that quite some time and the damage can be irreversiable. And how about cataract? Well over 50% will develop a cataract. If you do not have money for an operation, which is the case in the US (luckily not over here), you'll go blind by that.
In my view these two consequences make laser treatment well worth it, but Ido understnad that someone like youhas another persepctive. I have some troubl with your statement though as I am pretty sure you have no proof of it.  

4. To me it is simple: NAC clearly seems promissing. All animal studies have shown an effect and it seems to be dosedependant (very low dosage still had a significant effect for a short while). The subjective reports on it, by a researcher who also is an opthtomatologist, supports this. It does help, but it does not help everyone in his practice (and I do not know all too many medications that are 100% effective BTW) for everyone).

NAC has been used in eyes for well over a decade by at least 50000 people. There are no known adverse effects other than allergy to it (again, you'll always find people who are allergic to some stuff).

The costs are low, so in my view denying that it will work, saying it is snakeoil etc like some have done, is simply not based on science at all. If I need to prove things in facvour of something someone else, making this absolute statements, should do the same thing. I have come across many scientists or people with scientific background who fall into their own trap. They are critical of statements that lack data but do not realise that trusting their own, subjecrtive experience fals in exactly the same category.

I am not sure what you mean with your affiliation with that Univeristy? Do you mean you are in contact with those researchers or are active in this kind of research? If so, I am eager to hear what they have found!!
If not, I do not see how this remark is relevant. I have studied somewhere else too a couple of years ago, but that does not mean that I am somehow more qualified to say anything about research I have had nothing to do with. Don't want to be too harsh or something, but I am critical ;-)

Kinds regards!

[John C Hagan III, MD, FACS, FAAO]

1. Most people that have vitrectomies, even in their 30's and 40's usually do develop cataracts.
2. cataract surgery on a patient that has had their vitreous removed is not that much more difficulty than a standard operation. Most surgeons are quite experienced with it.
3. I think laser treatment of floaters is totally in appropriate, potentially harmful and rarely helpful.
4. I think the research you cite is in the earliest stages and unproven benefit.  And I went to the University of Missouri and know the faculty of MU.

JCH MD