N-acetylcarnosine can help maintain vision and allow you to …

Save Your Dog’s Eyes
While we frequently think fondly of dogs for their role as guides for the blind,
we far less frequently think of our beloved friends as susceptible to loss of vision

By Will Block

S ome diseases and health problems are common to both humans and dogs. Among these are diabetes, epilepsy, cancer, arthritis,* and cataracts (cloudy lenses). Often, cataracts in dogs result from diabetes, although they may also have a genetic base. In fact, 75% of dogs develop cataracts and blindness in both eyes within one year of being diagnosed with diabetes. The cataracts develop very quickly. Sometimes they even appear overnight!

*See “Protect & Restore Your Dog’s Health” in the July issue.

Alas, while we frequently think fondly of dogs for the role that they play as guides for the blind, we far less frequently think of our beloved friends as susceptible to loss of vision (thus needing their own guides—ironic as that might be). But dog blindness is true, especially for certain breeds. In fact, affected dogs show up with increasing regularity at the offices of veterinary ophthalmologists for evaluation. Underlying causes may include, as already stated, diabetes mellitus and genetic mutations, but there are others, including uveitis, congenital anomaly, trauma, toxins, and dietary deficiency. What can be done to help prevent or dispel the end of vision in our beloved “seeing eye” dogs?

Cataract Extraction Success Not Guaranteed

It is often presumed that surgical extraction represents the only method by which cataracts can be effectively treated. However, although surgical success rates have increased over time with refinements of surgical technique, surgical success is not guaranteed. Furthermore, surgery is considered to have failed when dogs develop painful and/or blinding complications such as endophthalmitis (inflammation of the internal coats of the eye), retinal detachment, or glaucoma.

However, while reported success rates, based on limited follow-up, exceed 85% to 90%, these numbers decline over time.1 While modern cataract surgery with intraocular lens implantation is the accepted standard, many dogs do not undergo surgery due to owner financial status, concurrent ophthalmic disease such as retinal degeneration, or concurrent systemic disease, which may preclude general anesthesia. In addition, when presented with the potential complications of phacoemulsification, some owners are more comfortable opting for medical management or no treatment at all.

† In modern cataract surgery, phacoemulsification refers to the procedure in which the eye’s internal lens is emulsified with an ultrasonic handpiece and aspirated from the eye. Aspirated fluids are replaced with an irrigation of balanced salt solution, thus maintaining the anterior chamber, as well as cooling the handpiece.

While some research has examined the complications arising after phacoemulsification, the authors of these studies are not aware of any studies that have assessed the complication rate for dogs with cataracts that are managed medically, or those that do not receive any therapy.1

Turning to a Successful Alternative Therapy

Is there a more successful, less invasive, not to mention less costly, route? N-acetylcarnosine eye drops show high potential for the nonsurgical treatment of age-related cataracts in canines.2 In a succession of studies, referenced in the mini-review by Wang et al,3 it is possible to see the evolution of the “use of carnosine as a natural anti-senescence drug for human beings.” The story actually starts in Russia in 1900, when carnosine was first discovered,4 and moves forward to the late 20th century when other Russian scholars, namely Severin5 and Boldyrev,6 made great contributions to research on the biological effects and medical application of carnosine. Since scientist Denham Harman, MD, PhD first suggested that free radicals are possibly one of the important factors causing aging and senile diseases (1956),7 the theory has been gradually accepted by scholars all over the world.

After Harman, many studies have found compelling evidence that the emergence and development of aging and senile diseases are intimately associated with oxygen free-radical-induced damage to cells. This damage has further been shown to leads to instability and malfunction of cells and consequently to the occurrence of aging and senile diseases, including atherosclerosis, diabetes, Alzheimer’s disease, and senile cataract, all of which have been related to free-radical-induced damage.

Additional research on the biological effects of various free-radical scavengers and antioxidants has demonstrated that they such nutrients have the ability to protect cells from oxygen free-radical-modulated damage and a normalizing function on the metabolism of cells. Furthermore, in studies with humans, N-acetylcarnosine has been shown to have substantial efficacy and excellent tolerability.

Reducing the Severity of Cataracts in Dogs

In a recent study, 30 dogs (60 eyes) were assigned to receive topical application of a standard FDA-approved eye drop solution to which 1% N-acetylcarnosine was added.8 The 30 dogs received eyedrops twice daily. A control group consisted of 15 dogs (30 eyes) that received placebo eyedrops and 10 dogs (20 eyes) that received no eyedrops. All of the dogs had cataracts at the start of the study. The animal eyes were evaluated at entry and followed up every 2 months for a 6-month period. The severity of cataracts observed in older dogs increased in 6 months as did the number of dogs affected. Cataracts were demonstrated by photodocumentation of dogs.

After 6 months, 96% of eyes treated with N-acetylcarnosine eyedrops showed improvements in the slit image and retro-illumination photographs of the lens. The most striking results were obtained using a 1% N-acetylcarnosine instillation in canines with age-related cataracts. The efficacy of the cataract treatment was determined, and the phenomenon called “melting snow” was observed upon the instillation of N-acetylcarnosine within only 1 month of long-term treatment. Melting snow refers to the disappearance of the white color that characterizes cataracts, the reversal of which starts from the periphery, following which the lens becomes more transparent. This is then attended by improved visual behavior in the dogs.

Results such as these, which have been duplicated by Williams et al,2 suggest that N-acetylcarnosine is an extremely important endogenous antioxidant for cataract prevention and reversal. N-acetylcarnosine and its bioactivated principal carnosine (which is activated after penetrating the eye’s barriers) operate as water-soluble, universal antioxidants at several levels to protect against oxidative stresses to the lens and glycosylation and crosslinking of the lens proteins. They also protect the lens proteins and membrane lipids from oxidative damage, thus preventing and reversing age-related cataracts in human and canine eyes.

Whose Dog Is it Anyway?

Unfortunately, while senile cataract is a very common disorder, many researchers appear to have over-looked the possibility of a nonsurgical nutritional approach to treatment to date. Given the high costs of the surgical procedure, along with the potential risk of surgical complications—combined with the undeniable fact that an artificial lens does not have the optical qualities of a natural lens—the use of N-acetylcarnosine eyedrops is a good deal, for you and for you dog.

The use of N-acetylcarnosine eyedrops has been demonstrated to be safe and effective, able to prevent and reverse cataracts in age-related eye disease in both dog owners and their ever loyal and loving companions.


  1. Lim CC, Bakker SC, Waldner CL, Sandmeyer LS, Grahn BH. Cataracts in 44 dogs (77 eyes): A comparison of outcomes for no treatment, topical medical management, or phacoemulsification with intraocular lens implantation. Can Vet J 2011Mar;52(3):283-8.
  2. Williams DL, Munday P. 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.
  3. Wang AM, Ma C, Xie ZH, Shen F. Use of carnosine as a natural anti-senescence drug for human beings. Biochemistry (Mosc) 2000 Jul;65(7):869-71.
  4. Gulewitsch W, Amiradzibi S. Über das carnosine, eine neue organische Base des Fleischextraktes. Ber Dtsch Chem Ges 1900;33:1902-3.
  5. Chasovnikova LV, Formazyuk VE, Sergienko VI, Boldyrev AA, Severin SE. The antioxidative properties of carnosine and other drugs. Biochem Int 1990;20(6):1097-103.
  6. Quinn PJ, Boldyrev AA, Formazuyk VE. Carnosine: its properties, functions and potential therapeutic applications. Mol Aspects Med 1992;13(5):379-444.
  7. Harman D. Aging: a theory based on free radical and radiation chemistry. J Gerontol 1956 Jul;11(3):298-300.
  8. Babizhayev MA, Deyev AI, Yermakova VN, Remenshchikov VV, Bours J. Revival of the lens transparency with N-acetylcarnosine. Curr Drug Ther 2006; 1:91-116.

Will Block is the publisher and editorial director of Life Enhancement magazine.

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