N-Acetylcarnosine Eyedrops for Cataracts in Dogs and Cats (Can-C, Bright Eyes NAC, etc)

A client recently asked for my opinion about the value of some over-the-counter eye drops purported to treat cataracts in dogs and cats. Not having read much about this product, I did a little research.

What Is It?
There are a number of eye drops marketed for prevention or treatment of cataracts in humans and pets. Most commonly, they contain a chemical called n-acetylcarnosine, which is made up of a couple amino acids and an acetyl group. In vitro research suggests this chemical has anti-oxidant effects, so it has been hypothesized to prevent or reduce the gradual opacification of the lens of the eye through this mechansism. As I have pointed out before, the role of oxidative damage in disease, and the value of anti-oxidant therapies, is a developing area of research. Many of the exuberant and enthusiastic hopes in this area have proven false, so while it is an area deserving further investigation, claiming something is an anti-oxidant is not automatic validation of its safety or benefits (e.g. 1, 2, 3).

Does It Work?
There have been a number of studies of n-acetylcarnosine, both in vitro studies and clinical trials in humans. Interestingly, almost all of these appear to have been published by the same researcher and his team, Dr. Mark Babizhayev. A clinical trial was published in 2001 (and it appears the same data was published again in a different journal in 2002, which if true is quite a significant science no-no). The trial was randomized and controlled in a small number of patients, and it appeared to show significant changes in a number of objective measures of cataract severity.

I am not familiar with the specific techniques used to measure the disease or response to treatment, so I will presume they are standard and appropriate measures for this kind of study. One thing that is not clear from the published report is whether the individuals making these measurements were blinded to the treatment status. This obviously has a significant bearing on the reliability of the results, especially when they stem from only one researcher, as such debacles as the Benveniste affair show.

A number of subsequent papers have been published by Dr Babizhayev and his team, mostly in vitro or lab studies investigating properties of n-acetylcarnosine, not clinical trials. Dr. Babizhayev has also become the leader of a commercial firm marketing n-acetylcarnosine for cataract treatment, and many other uses (including skin care, wound care, respiratory disease, and neurologic disease).

This commercial effort, and the spreading of claims for n-acetylcarnosine to a wide range of apparently unrelated applications, does raise some questions about the reliability of Dr. Babizhayev as the sole source of scientific validation for this compound. Overall, the status of the evidence for use of n-acetycarnosine for cataracts in humans is best summarized by the Royal College of Opthalmology:


The evidence for the effectiveness of N-acetyl carnosine eye drops is based on experience on a small number of cases carried out by a Russian researcher team. To date, the research has not been corroborated and the results replicated by others. The long-term effect is unknown.

Unfortunately, the evidence to date does not support the ‘promising potential’ of this drug in cataract reversal. More robust data from well conducted clinical trials on adequate sample sizes will be required to support these claims of efficacy.

Furthermore, we do not feel the evidence base for the safety is in any way sufficient

Unusually, there is actually some clinical trial evidence in veterinary species as well. An uncontrolled, unblended pilot trial has been published on an n-acetylcarnosine product (not the one Dr. Babizhayev sells) in dogs with cataracts.

David L Williams, Patricia Munday. The effect of a topical antioxidant formulation including N-acetyl carnosine on canine cataract: a preliminary study. Vet Ophthalmol. 2006 Sep-Oct;9(5):311-6. The results showed marginal improvement in all groups, though it was only significant in patients with 2 out of 5 types of cataract treated. However, subjectively owners reported improvement in 80% of the subjects.

Dr. Williams  has apparently performed a blinded, placebo-controlled follow-up trial on this product which did not show any benefits (in fact improvements were greater in the placebo group than in the treatment group), showing once again the importance of proper controls for bias, confounding, and other sources of error in clinical trials. Unfortunately, it appears unlikely this trial will be published for reasons which are not completely clear, though one implied issue is that journals are often reluctant to accept papers that show negative results, which are less exciting for readers than positive studies. All of this is, of course, through word-of-mouth among veterinarians, so I cannot confirm it is true.  

Is It Safe?
I have not found any reports of adverse effects from ophthalmic application of N-acetylcarnosine itself, and given its chemical makeup it seems unlikely to be hazardous. As usual, products containing this agent are not regulated as licensed medicines are, and there is no way to ensure label accuracy, proper manufacturing quality standards, or the safety of other ingredients that may be included with the N-acetylcarnosine. 

Bottom Line
The theoretical arguments for why this drug might be useful I the treatment of canine cataracts are plausible but largely unproven. There is limited clinical trial evidence in humans suggesting a benefit, but this has not been replicated and is at high risk of bias. The limited clinical trial evidence available in dogs does not suggest a benefit. There are minimal safety concerns with products containing N-acetylcarnosine.

This entry was posted in General. Bookmark the permalink.

170 Responses to N-Acetylcarnosine Eyedrops for Cataracts in Dogs and Cats (Can-C, Bright Eyes NAC, etc)

  1. Katie says:

    Yes,” dogowner,” it is Skeptvets responsibility to conduct he or shes own study before telling everyone on here we are all stupid.. You think one person died from silicone?..Believe me, just “one” manufacture has paid out billions to the women and their families..The manufactures fought it for fifteen years but lost..They knew it was harmful from the start..Why don’t you let them inject Freon in your chest because that is what they did..Freon was just one of many chemicals that was put in the silicone..No different from the chemicals they use that is on the back of carpets..The manufactures did say that only one woman in 500 would get Lupus..I knew many and some that have died..The studies were found to be bogus..Yes, I know because I have had four surgeries to get that sticky mess out of my chest..Lost 14 lymph nodes and have three auto-immune diseases..The doctors said they will never get all of the silicone out of my body. I was part of a class action lawsuit of 500,000 that got sick who sued and won..That was from just one manufacture..We all had to have medical reports from our doctors..Now women have to sign a paper that if they get sick they can’t sue..Takes about eight years before you get sick and boy, do you get sick!..That is why the doctors are telling women now to replace the implants every three-five years..Sorry, but it upsets me when someone believes the studies and just close their minds to the truth.. Getting back to the Can-C..For the first time my dog walked across the room and picked up one of the cat toys and took it to her little bed..I was so happy to see that..I have also noticed that she wants to stay outside for longer periods of time..I have a hard time keeping up with her..I think everyone should try the Can-C and see for themselves..I know she still has the cataracts but they must be thinning out..They look smaller..It is worth the small amount of money to do something, anything, for your beloved pet..

  2. Katie says:

    Guess my last post won’t be seen but that is ok..Don’t agree with Skeptvet..

  3. v.t. says:

    Katie, posts on the blog are not automatically approved, for the purpose of keeping spammers from creating havoc and other reasons.

  4. LRB047 says:

    There is no way on God’s green earth that I would ever use eye drops that have not been clinically proven to cure cataracts that my dog has! I have a 16 month old Havanese (pure breed) male who is loved in our family as much as our children are. He is not a pet….he is a member of our family! Unfortunately he had a trauma to his left eye. and even tho we took him to our vet immediately and she put him on an eye drop and an eye gel within 2 weeks it had turned into a cataract. Our vet examined his eye 3 times within that 2 week period as best she could with the equipment she had to work with and on the 3rd visit she also examined his right eye. At that time she told us that he had a cataract that was just beginning in his right eye also. She suggested we take him to a veterinary ophthalmologist ASAP to see what our options would be for our sweet baby Max. Needless to say we were devastated! How could this happen to such a young dog that we treated like our baby? We didn’t know before hand that Havanese are predisposed to get cataracts and at a young age. So we made an appointment with the veterinary ophthalmologist in Lansing, Mi which was an hour and a half drive from our home. When we took him in they tested his eyes with their special equipment, and verified that he did indeed have immature cataracts. He left it up to us to make the decision as to what we wanted to do (have the surgery or let him go blind); and before he even finished his sentence I told him that over my dead body would I even consider letting our young baby go blind! We were told that the c ost would be $2,800 for one eye, and if we wanted to have both eyes done at the same time it would cost $3,480. We already knew beforehand that it’s cheaper to have them both done at the same time, so we never hesitated. We are by no means wealthy people, but we do have a credit card with 0% interest for a year so that is how we are going to save our little guy’s eyes. I don’t care if it takes us the rest off our lives to get it paid off, there is no way I would even consider letting Max go blind at such a young age. Some people might think we are crazy for doing it, but I really don’t care. He is the love of our lives.

  5. Sandra says:

    Highly amused by this exchange. Skeptvet says clinical trials say it doesn’t work when in fact several seem to say it does and one seems to say it doesn’t. If you are a pet owner for whose pet it did work, Skeptvet wants you to think it’s all in your imagination. Luckily for you, your pet doesn’t care. Thank you for the information, everyone. I am thinking of trying it on my favourite cat, who has cataracts.

  6. skeptvet says:

    You’ve missed the point.

    The published clinical trial suggested there might be some benefit, but methodologically it had some limitations that made a confident conclusion impossible. A follow-up trial with a better design was conducted which showed the product didn’t work. Unfortunately, that will never be published, as negative trials so often aren’t, because it was sponsored by the manufacturer selling the product.

    Anecdotes simply aren’t reliable, even if they seem really convincing to the people offering them. Sure, someone can use the product and say it worked. But someone can sprinkle holy water on their pet and say it cured cataracts as well. What’s the difference? In all the millennia we relied on such anecdotes, we made virtually no progress in medicine. In the couple of centuries since we began to rely on scientific evidence, we’ve doubled our average life expectancy, dramatically reduced death and suffering, and eliminated entire diseases that plagued us for centuries. You are free to go back to relying on anecdotes and ignoring of science, but I don’t recommend it.

  7. Dr Chris says:

    I have been using the Can C drops on and off for a couple of years. Peripheral vision is clearer and the central region more transparent. I made Photoshop images to keep a record. When I stop taking the drops this improvement is quickly lost however. Talking of bias very few ophthalmic surgeons would like this treatment to work, lamentably.

  8. skeptvet says:

    I don’t know what you mean by “ophthalmic surgeons,” since most specialists in this area are ophthalmologists and treat cases either medically or surgically as indicated. They have no malign motive to pursue surgery where it isn’t indicated. And as I often explain, though people seem to have difficulty understanding, uncontrolled individual experience doesn’t control bias the way controlled clinical trials can, and doesn’t itself constitute proof for or against anything. If it did, we wouldn’t need science at all, yet history strongly suggests we do.

  9. Katie says:

    Everyone should stop trying to make Skeptvet believe that can-c works..She/he has tunnel vision and is a hard-head..The heart doctor has had my husband taking Vit. E for years but Skeptvet says that Vit E is useless..What does that tell you?..I believe in the can-c because it has helped my dog’s sight and I will continue to use it..My dog has much better vision now and has a better life thanks to can-c drops..

  10. skeptvet says:

    Yes, believe whatever you like. Science doesn’t matter, just what you happen to think.

  11. Katie says:

    Science!!! Believe what “you” think! Same thing, right? You believe the lies they tell you on studies ..Tell me why you don’t believe in Can-C..Don’t tell me about the studies..Tell me you have tried it on animals to see for yourself if it works..

  12. skeptvet says:

    No, the difference is clear. My opinion and personal experience is irrelevant because I understand that uncontrolled individual judgment is often unreliable. We used the “try it and see” approach for thousands of years, and in all that time made almost no progress in preventing or treating disease. A couple of centuries of relying on science instead has yielded dramatic and unprecedented improvements in our health. You are the one who seems to feel your personal experience is so flawless and reliable that it trumps the scientific research. And with faith like that, it wouldn’t make any difference even if I told you, “Yes, I’ve tried it on dozens of animals and it didn’t work.” You’d still believe it worked for you.

    So no, my trust in science to achieve an accurate understanding of nature is not the samw as your faith in yourself and your experiences.

  13. Katie says:

    I guess in my case seeing is believing..I never have relied on studies because there are too many products on the market “proven” safe when in fact millions have died using that so called safe product..I don’t think people on here would lie in saying the can-c is working. Why can’t you suggest can-c to pet owners since there are no side effects..?{Funny, you believe those studies..} Can’t you soften your heart a little especially to those who can’t afford the over priced surgery for the cataracts…If I were a vet I could maybe sleep at night knowing I gave hope to some who were heart broken to see their pet go blind..Can-c is worth the try, don’t you think..?

  14. skeptvet says:

    You are deeply mistaken if you think it is more compassionate to rely on anecdotes than on scientific evidence. Reliance on anecdote without science harms, even kills many more patients than seeking the truth through science, that’s the whole point. My goal here is not to deny animals effective treatments but to warn people about the risks in using unproven remedies or those shown to not work. When the research evidence shows this product doesn’t work, it helps no one to say “try it anyway and good luck!” False hope and the comfort of doing something even when it isn’t going to help don’t benefit pets. In fact, these things just make people feel better while letting their pets continue to suffer.

    You are free to believe what you choose and to ignore science if you want to. But there is no moral high ground in doing so, nor in telling others to follow your example. Knowing the truth is the best way to really help, and science is a lot more reliable a path to the truth than haphazard personal experiences.

  15. Barbara Irwin says:

    My 12 year old Yorkie is both deaf and has bilateral cataracts. I’m planning on trying the drops.I read all the research and chose to try them. I can’t loose but maybe it would work. I feel so sorry for her. Her quality of life is not good and if I can try something that could possibly work I would feel I had at least tried.

  16. Barbara Irwin says:

    The scientific research never claimed the drops didn’t work. What I understood was there was not enough research done to prove the drops did or didn’t work.

  17. skeptvet says:

    The published study was equivocal. However, a follow up study was done with proper controls which showed the drops didn’t work. Unfortunately, I have been told that the company is not going to allow publication of this negative result. This is the same company we are supposed to trust our pet’s eye health to.

  18. v.t. says:

    If I were a vet I could maybe sleep at night knowing I gave hope to some who were heart broken to see their pet go blind..

    I’m pretty sure vets sleep much better at night knowing if they have explored and offered options that had evidence behind them, as opposed to “giving hope” where there is none. Giving hope with nothing does nothing for the pet who needs proper care.

  19. dogowner says:

    “If I were a vet I could maybe sleep at night knowing I gave hope to some who were heart broken to see their pet go blind”

    I would feel terrible knowing I’d lied to someone about their pet. It’s not going to help the pet to lie to them- it just means they go through the stress of getting given a useless treatment.

    And I don’t want my vet to lie to me either. It’s not their decision to make. If they would lie about something as important as this, what else might they be happy lying about? I’d rather a skeptical vet any day. At least I can trust them not to manipulate me for profit (sorry, ‘give me hope’).

  20. Tom Noneman says:

    A quote from the article that started this, if I might (quotes mine):

    – Dr. Williams has “apparently” performed a blinded, placebo-controlled follow-up trial on this product which did not show any benefits (in fact improvements were greater in the placebo group than in the treatment group), showing once again the importance of proper controls for bias, confounding, and other sources of error in clinical trials. Unfortunately, it appears unlikely this trial will be published for “reasons which are not completely clear”, though one “implied” issue is that “journals are often reluctant to accept papers that show negative results”, which are less exciting for readers than positive studies. “”All of this” is, of course, through word-of-mouth among veterinarians, so I cannot confirm it is true.”

    I can tell by the tone of the article you are a deeply caring person, trying hard to be fair and objective, and ultimately save people and their pets from needless pain and suffering. Feel free not to print this, but please consider it.

    Is the above quote your “scientific” basis of rejecting Can-C and its relatives? Is the second trial absolutely confirmed? What does “word-of-mouth” refer to?

    Also, have you ever, even once, seen a reported negative side effect of Can-C or its components? Even by (unreliable) regular ex-users? More people will typically complain and warn others than praise a product. Some say it did not work, but none I have found say it caused harm. Especially this product, because there are many human users, and humans can explain is something caused problems. There would be fireworks and litigation if this was causing problems. (And yes, just like other products, they would eventually be traced back to this product.)

    Also, have you – ever – heard of cataracts improving spontaneously? A rare occurrence, according to standard medical knowledge: http://www.ncbi.nlm.nih.gov/pubmed/7206575

    In old dogs? Why these “foolish” testimonials saying people have seen it happen, to any degree? Are they all fakes? Do they want to raise false hope? (What is the most likely answer, Mr. Watson?) You maintain personal testimonials are unreliable, which is often true if perfection is required, yet our entire court system is based on the unreliable, feeble memories and stories of people trying to recall what they have seen and heard. Not all evidence is deemed admissible, but by your so-called “scientific” standards none would any qualify.

    Good science is good. Bad science is bad. Extremism is bad, either way, be it too strict or too loose in its requirements. The best swimmer sinks in a straight jacket.

    You must never, ever completely discount personal experience. Weigh it – you do not have to buy it. (For the record, I am a huge skeptic, too.)

  21. skeptvet says:

    To be clear, I am not “rejecting” the product. I am saying that there is very little evidence and that the best evidence we currently have, a controlled scientific trial, shows it does not work. At this point, that means there is little reason to try it. Additional evidence could come up that changes that conclusion, since all scientific conclusions are provisional. But the company is unlikely to put more money into studying it when it has allegedly suppressed publication of negative evidence already and when it can profit from selling the product without proving it works.

    As for testimonials, they can never prove or disprove anything, only suggest hypotheses to be tested. So personal experiences do not tell us anything useful. If you are arguing that we should consider using this product despite its failure in the only trial done so far because there are anecdotes that suggest it does work, then you have to be willing to accept any product for which there are positive anecdotes, which has proven in the past to be a poor way of choosing which medical therapies to use.

    The world is full of miracle treatments for disease, and some choose to try things indiscriminately, or based on unreliable evidence such as anecdotes regardless of the evidence. They are free to do so, but I think the story of healthcare in the last 150 years or so is very, very clear that making choices based on scientific evidence when it is available is a better bet. This is not closed-minded or “rigid” or whatever pejoratives you choose to describe it, it is simply a rational strategy with a strong history of more success than the easier alternative.

  22. Jacques says:

    I just stumbled on your conversation – forgive me for intruding.
    There is a third factor between your two viewpoints. A few years back I facilitated meetings for researchers in the field of health who were meeting to discuss possible ways to surmount new limitations being placed on the types of subsidies they could get from the powers that be. In some areas of research, ‘pure’ research is dependent on subsidies, because to depend on funding from commercial interests (pharmaceutical companies, etc.) is to automatically bend the results of your work towards the profitability desired by the commercial interest. If, in the process of developing a product for a company you stumble upon a new, life-improving compound, but you find out it grows on trees, you will not get funding for that result.
    There was to be little or no money for pure research. To get money from the government you had to show that there was ‘some’ stimulus for the economy to be found in the research, a profitable result of sorts. Some of the researchers I worked with were deeply affected by this change. Some wanted to just plain quit. Some were going to the’dark side’ and were going to try to profit themselves.
    Also, resistance to change is a major factor, if only because the more you invest yourself in a way, a manner, an action, the more you are embedded in it, and the more resistant you become to new suggestions. In this, age plays a large part.
    Add to that the bias of professionals who may have vested interests, some of them fueled by co-ownership of labs somehow located in the same building, or side door partnerships with aforementioned commercial interests (say you don’t believe lobbying is evil ….) and you wind up with a scenario that makes you sound like a conspiracy theorist if you voice your opinion.

  23. skeptvet says:

    Funding is a serious source of bias in research. There’s no doubt about that. However, that does not translate into the claim, often made by supporters of alternative therapies, that such therapies must be accepted without good evidence because such evidence cannot or will not be obtained. For one thing, the supplement industry is a multi-billion dollar per year industry with easily adequate resources to test its own products scientifically if they chose to. However, because they are not compelled by regulation to do so the way pharmaceutical companies are, they do not. Likewise, lots of people make a profit selling alternative therapies, and they have n obligation to use some of that money to scientifically evaluate the products and services they sell if they want to be able to make claims about safety and efficacy.

    Also, it is important to realize that most “promising” therapies investigated never make it to market because of problems uncovered by rigorous research. Protecting the public means accepting that even popular therapies that seem based on sound theories are often wrong, and we shouldn’t be making claims about their safety and efficacy without adequate evidence.

    Finally, research resources are limited, and they should be devoted to the most promising therapies, which means those that have some sound basis in established science. When something blatantly contradicts established knowledge, such as homeopathy, there is no reason anyone should expect industry or government to support research into such a therapy just because some people have faith in it based on anecdote.

  24. Jacques says:

    I think that a firm opinion is a form of blindness, almost as bad as fundamentalism. I don’t know you but I think you chose your name with very good intention, the scientific skepticism that must reveal the naked truth, unadorned by our imagined construct of the universe. But, caught up in all this rethoric, remember that advancement in science is all too often serendipitous and that the Aspirin came from the bark of the Willow. An inquisitive mind is certainly the portal to wisdom when guarded by a skeptical spirit such as yours, but both parts are needed.

  25. skeptvet says:

    The flaw I see in your comment is that you see skepticism as closed-minded or somehow ignorant of the role of chance in discovery. The exact opposite is true. Skepticism is the conscious choice to not draw a conclusion until there is good evidence to justify doing so, to acknowledge that much which seems patterned and purposeful is in reality governed by chance, that all knowledge is provisional and subject to change, and that individual observation and judgment is fallible and works better when supported by the systematic efforts of the group.

    The proponents of many of the practices I criticize would lose their minds much earlier than I do based on acceptance of the opinions and beliefs of others and a failure to recognize the role of chance or the limitations of their own observation and judgment. I frequently change my views as the evidence changes, whereas the proponents of judgment by anecdote fix their belief in one spot as an act of faith and are rarely moved. I once wanted to learn acupuncture because others told me how powerful it was. I then investigated the evidence and came to understand that it was, in fact, an elaborate placebo. This is not the path of a closed mind but of one open to the possibility that things may not be as they seem and that our beliefs should always be subject to revision.

    And note, we don’t take willow bark for pain, we take aspirin because we found, through science, that aspirin is a more reliable, predictable, and useful remedy than willow bark tea. The substance was there in the plant, yes, but it took science to make take full advantage of it.

  26. Mike Beezel says:

    I found this article http://www.berkeleywellness.com/self-care/over-counter-products/article/cataract-drops and I know it’s not saying it’s the miracle cure and that more testing is needed, but it does say there is potential and I’d like to think that from the source, it’s not biased. I’m not an expert, but just someone looking for answers as our 4 month old puppy has gone blind from cataracts and we’re just not able to afford $4,400 for the surgery not counting travel costs and follow up visit/prescription costs. Thoughts?

  27. skeptvet says:

    The article you link to says pretty much the same thing I have in the post, which is that there is some suggestive but unconfirmed evidence of effects in people. In dogs, the best evidence is that there is no benefit. And it is unlikely to have significant risks, though we cannot be sure without proper study. Clearly, this means that from a medical point of view surgery is a far better option since we know it works. But if surgery is not an option for logistical or financial reasons, sure gambling on an unproven remedy may be a reasonable decision. My goal here is just to give people the information they need to make an informed choice, but of course the choice is up to you and has to be based on the details of your situation.

    Good luck!

  28. I. Rau says:

    My 12 year old shih tzu was developing age-related cataracts before she was diagnosed with diabetes 3 months ago. About a month ago she became blind, walking into objects and walls, unable to find her food and water dish. I have been using Can C drops for 1 week and already my husband and I have noticed an improvement in his vision. He is no longer walking into walls and objects. I can’t wait to see what happens in the months ahead. But this level of improvement alone is enough for me. After all he is an older dog and he had deteriorating vision to start with so I don’t expect huge improvement. But the improvement we’ve seen is certainly worth the cost of the drops.

  29. skeptvet says:

    If only knowing whether or not a treatment worked was that simple, then we wouldn’t need science at all. But people have thought the same about everything from bloodletting, to magic, to ritual sacrifice and been wrong, so we ought to be a bit careful about assuming we can judge on the basis of such anecdotes.

    A few things to think about:

    Don’t Believe your Eyes (or Your Brain)

    Medical Miracles: Should We Believe?

    Testimonials Lie

    Alternative medicine and placebo effects in pets

    Placebo effects in epileptic dogs

    Medical Practices Once Widely Accepted that Proved Ineffective or Harmful when Studied Scientifically

  30. Hope Gibson says:

    We have a 9 year old minature pincher we love him so he is diabetic and has cataracts in both eyes surgery is rediculasly expensive no way we can pay 4000 for it so we are using Can C Eye Dops just started using on the 13 th April we will let you know how it works and wish very best for all of you who are in same situation as we are God bless.

  31. Marius de Jess says:


    There are people who have witnessed the good work effected with N-Acetylcarnosine eyedrops for cataracts in dogs.

    You are, forgive me, not into actual genuine work of contacting the witnesses and talking with them, to detect whether they are reliable or not.

    Suppose instead of bringing in such words like anecdotal accounts to insist on there being no evidence or no scientific researches, etc., you do undertake to contact the witnesses, and find out whether their accounts are reliable, and their dogs really had cataract, and the dogs got better with N-Acetylcarnosine eyedrops.

    That is one task that you can do without spending a lot of your personal time and labor and money, but for the sake of discovering the fact and the truth.

    So, please do something positive than always bringing in words like anecdotal accounts, no scientific researches, etc., to maintain a wall of impregnable hostility against incidence of good remedies having been availed of by people who report on them.

  32. Marius de Jess says:

    The phrase anecdotal account is already a negative prejudgment, that is why it should not be used in referring to reports by people, who have themselves experienced improvement in the use of a substance or procedure in his medical concern.

    Dear Skeptvet, you can do a good job without investing too much of your time and material resources: by contacting people who have personally experienced improvement, to detect exactly what they have experienced and find out what are the causes or circumstances, etc., why and how they experienced the improvement.

    That procedure is scientific.

    You will then contribute to the knowledge of how substances and procedures work with people who do experience improvements.

    What I notice time and again is the closed heart and mind of die-hard skeptics to anything that has not been subjected to the prescribed ways and means established by fellow skeptics for proving or disproving something to have occurred, or some substances to have done a good effect with people who do experience improvement from an event or procedure and/or a substance.

    Forgive me for the use of the phrase, die-hard skeptics; but that is what I observe with such skeptics, they are die-hard; like when they are confronted with facts they will resort to argue that we cannot trust our senses, because what we perceive and what really happens in objective reality can never be ascertained 100%, as our human knowledge founded on ultimately sense perception is unreliable.

    There, they will win every argument with that kind of a principle, namely, that sense perception is ultimately unreliable.

    What about someone having been killed and buried and then his bones remaining after twenty years are now taken to another grave for re-burial, are you die-hard skeptics still going on and on and on insisting that human sense perception is inherently and ultimately unreliable, and therefore we cannot be sure that that subject had died?

  33. skeptvet says:

    Sorry, but you are wrong. “Anecdotal evidence” is of low value not because of some kind of prejudice on the part of skeptics but because of the well-established and understood cognitive errors the human mind makes when trying to establish causation. The entire foundation of our society, including the technology we are using to have this discussion, is based on the ability of science to see more and more clearly than unaided human beings, and the fact that you don’t understand or accept that is a testament to the common, and dangerous, phenomenon of a scientifically uninformed population dependent on the fruits of the very scientific methods they reject when these challenge their personal experiences and beliefs. As Carl Sagan presciently put it so many years ago, “We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. This is a clear prescription for disaster.”

  34. v.t. says:

    Marius de Jess ,

    It isn’t up to skeptvet to prove whether or not the product works. It is up to those making the miraculous claims and selling it and profiting handsomely without scientific evidence to back up the claims.

    Asking skeptvet to, shall we say, “interview” people with their personal stories, would be just that – an interview, that’s the farthest thing from conducting clinical research.


    A die-hard skeptic

  35. NewsView says:

    A lot of older dogs develop cataracts just like older people. Older dogs, as my vet explained, are not candidates for elective surgery. Cataract surgery is in most cases elective, and so it’s out of the question. Now while it is true that the ingredient in Can-C and products like it is not thoroughly tested it has been tested sufficiently to be permissible for use in humans, and you can buy it in the United States not some fly-by-night Internet pharmacy out of India or Mexico. So if it’s generally recognized as safe for human use — and we know that almost no products are offered to humans without animal testing beforehand — I’m not going to be paranoid that my 14-year-old dog will be the worse for it.

    I’m willing to try Can-C on my dog because 1) the product is sold for human use, which is a higher standard in the first place, and 2) surgery is not an option for elderly dogs. In this case, my dog’s lenses have been clouding slowly for the past 5 years and she can still see. Even so, I don’t want her to go blind slowly but surely. If I can halt the progression — mind you, not with the expectation of eliminating them — I will consider it a success. I’m going to give this unscientific trial 90 days and if any dramatic improvements (or adverse events) take place I will report back. The reality is, in closing, that it may take more anecdotal reports to help promote the idea that further study is warranted.

  36. skeptvet says:

    There are a couple of misconceptions here that might influence your reasoning.

    1. “Older dogs, as my vet explained, are not candidates for elective surgery. Cataract surgery is in most cases elective, and so it’s out of the question.”
    This is simply untrue. Age itself is not a major risk factor for anesthesia nor a contraindication to surgery. Certainly, older animals may have diseases other than the one you wish to treat, and this can influence the risk of surgery. And there may be other reasons your dog is not a candidate for cataract surgery. However, just because he is old doesn’t mean he can’t safely have a procedure that might cure a problem that can lead to blindness. So I wouldn’t just assume this is not an option for you. I would consult a board-certified veterinary ophthalmologist, who will be much better able to assess the risks and benefits for your dog than your regular vet.

    2. “So if it’s generally recognized as safe for human use — and we know that almost no products are offered to humans without animal testing beforehand”
    Non-prescription supplements like this are not regulated or tested to any significant degree. The assumption of safety is a legal fiction built into the laws that prevent appropriate regulation of such products, and one of the biggest problems with these products is that people assume that because something is legal to market it has been tested for safety and efficacy. There is abundant evidence of such products causing real harm, and while I don’t have specific reasons to believe this product is dangerous, the fact is that without appropriate testing, which has not been done, we cannot be certain.

  37. Love my dogs says:

    Hi, I want to thank you for providing a valuable public service. I was indeed skeptical about the claims, and I appreciate your detailed explaination of the results of the “study”. The limited clinical evidence is enough for me to proceed with cautious optimism if I do in fact decide to purchase the product.

    I wondered if you would share your opinion of cataract surgery for a 7 year old Bichon Poodle mix, and an 11 year old Bichon. I would definitely spend the money if it would improve my furkids quality of life.

    Thank you again for the good work you do.

  38. skeptvet says:

    In general, cataract surgery definitely can improve quality of life, and both 7 and 11 are not very old for small dogs. Ultimately, you should find a local veterinary ophthalmologist and ask detailed questions about the risks and benefits to help you make a decision.

    Good lick, and thanks!

  39. v.t. says:

    Skeptvet needs a proof-reader. Sorry, skeptvet, couldn’t resist 🙂

  40. skeptvet says:

    You volunteering?? 😉

  41. v.t. says:

    Not unless you want more of the same!

  42. bobbyb says:

    Hello – I have a 10 year old JRT who had a cataract show up overnight in one eye and the vet ( next day) found the beginning “V” form in the other eye ( not visible yet without his light). I have been using the OctuGlo and drops for 3 months in both eyes. When I have the better eye checked again it should be a good test for whether the drops w/ vitamins work. If the beginning cataract hasn’t improved then there is little hope for the larger one.
    I am writing about the new Lanosterol tests and products. I see several canine products on Amazon but nothing is available. Sort of putting the product out there before it is even available. Perhaps it was pulled? It seems that the testing for this product done on dogs was more controlled with significant results. Do you have any information or advice. Thanks

  43. skeptvet says:

    The study published in Nature involved both topical application and injection into the eye of the Lanosterol. Only 7 dogs were used, and no clinical trials or toxicity studies have been done yet. This kind of early animal model of research is an important part of the testing process, and seeing some effects suggests that a benefit in real patients is possible, but how the drug might be used and what the risks and benefits really are is so far unknown. It’s a big roll of the dice to try these things without such information. It might help, it might do nothing, or it might cause hamr and make things worse, and nobody really knows yet.

  44. Susan says:

    I TOOK THE N-acetyl-L-carnosine DROPS MYSELF. I just started giving the drops to my dog because of the cost and after reading the possible problems associated with the surgery, detached retina, glaucoma, severe headaches. Why am I taking a chance? About five years ago, I suddenly could not even read my cell phone. I went to get glasses and found out I had cataracts. I had no side effects from the N-acetyl-L-carnosine. I don’t remember how long it took my for my vision to improve, but it wasn’t long. DOES ANYONE KNOW THE INSTRUCTIONS FOR GIVING IT TO DOGS? You can’t get the dog to keep her eye closed for 60 seconds.

  45. bobbyb says:

    I asked the manufacturer about the 60 second thing and they said don’t bother – 4 times a day.

  46. andrew torok says:

    With regard to the Lanostertol, the tests are very promising. My question is: Why have several sites, including Amazon, offered the drops for sale but all of them now state that the drops are no longer available and will not be. The university where the drops were most recently tested spun off production of the drops as a separate venture. Universities often do this. I contacted the lead researcher with my question as to why the drops are no longer available and he did not answer. I suspect drug companies et. al. have bought up the patents (and yes, there were patents granted) and paid the researchers off.

  47. CD says:

    Hi. I am new to this website — and it very thought provoking!
    One thing I may have missed in the postings of this thread is the progression of cataracts in general. I may be wrong, but in my recollection from waaayyy back in vet school is that in some dogs, cataracts will sometimes mature and shrink away from the edges so that in some instances some patients can see around the margins peripherally, especially when the eye is very dilated in low light. Sometimes the lens even luxates posteriorly — allowing light perception. Some dogs see light and shadows through their cataracts under certain circumstances. Could it be possible that some people who are observing apparent improvement may be really observing the effect of these phenomena? Also of note, is that dogs, unlike people are not quite so dependent on their vision and have amazing mapping abilities — how many of us have seen someone bring their pet in with apparent recent vision loss but clearly on exam, one can see that this has been ongoing (diabetics excepted) and that only recently has the deficit become more obvious — a change in the furniture arrangement, a tipping point in the progression.
    Obviously, as an “intelligent” human, if you start “doing something”, you expect/anticipate and thus bias your observation of the result — it is in the nature of our minds. I don’t know anything about these drops per se and maybe they are or are not harmful or helpful. (I myself have been the “victim” of placebo effect many times, frequently self-induced, and was glad to find it worked –haha, but I had to accept the fact of it.) But it is important to understand that these anecdotes do not prove cause-and-effect regardless of how hard we look for it. (Witches float and the innocent drown, right?) Hence the great need for evidence-based medicine…. and TRUTH in publishing of ALL the evidence — good and bad and ugly. Go Skeptvet! We need a voice to make us think — hard and overcome the weaknesses of our observation. Just wanted to say thanks and loving your website.

  48. skeptvet says:

    Thanks for the comment, I’m glad you found the site useful!

  49. Dr. Miguel Ettema says:

    As a veterinarian myself, with a 16 year old German Shepherd mix with advanced nuclear sclerosis of her eyes, I have been interested in any non-surgical procedures that might improve her situation.

    I was hopeful at first whe I read about NAC, but the double-blind trials aren’t particularly promising when it comes to true cataracts… but I do wonder if there would be some benefit in regards to nuclear sclerosis. Even with my wariness of testimonials (I am all too familiar with clients blinding themselves to the realities of their pets’ issues; hope can be a powerful manipulator of people, as can denial, sadly) I think I shall give the drops a chance with my own dog, who is otherwise not a great candidate for surgery due to her overall general poor fitness. I will organise with a ophthalmologist colleague of mine to do some lens photos using atropine to guage the efficacy for my dog.

    Frankly, I still believe physical surgery is the best option for cataracts when it comes to severe cases in dogs, especially with the subsequent problems they can create; the person who suggested surgery is always a last resort is obviously not medically inclined, for there are numerous situations where surgery is the best – and should be the first – choice. Closed pyometron, anyone?

Leave a Reply

Your email address will not be published. Required fields are marked *

This blog is kept spam free by WP-SpamFree.