Cats get more viral eye infections than other animals, and feline herpes keratitis is one of the most common. Feline herpes keratitis (FHK) is a chronic condition caused by the herpes virus, which is similar to the Herpes simplex virus that appears as fever blisters in humans. FHK is also a secondary infection resulting from feline viral rhinotracheitis.

In both cats and humans, the virus lives in the nerves of the face and becomes activated during times of stress. Flare-ups in cats are usually associated with the stress of boarding, changes in the weather, the introduction of a new cat in the home, or other health conditions. In general, anything that stresses your cat or alters its daily routine can trigger re-activation of the virus. Once a cat contracts this virus, it has it for life. So it's very important to strengthen your cat's immune system in order to reduce flare-ups.

Since feline herpes is a viral infection, it's important to boost your pet's immune system with nutritional support. Immugen from Thorne Research is a powerful immune support formula containing Coenzyme Q-10 (CoQ10), Reishi Mushrooms, Astragulus, caratenoids and several vitamins with antioxidant properties. CoQ-10 acts as an antioxidant protecting cells against free radical damage. In humans it has been shown to enhance immune function and rejuvenate the body on the cellular level. It may also provide your pet with the immune support it needs to counteract the underlying cause of its infection. Vetri-Lysine and Spry are often suggested for cats with Feline Herpes because their main ingredient, L-Lysine suppresses blood arginine levels, thereby inhibiting herpes virus replication. 

Symptoms of Feline Herpes Keratitis

  • Keeping eyes partially closed
  • Pain
  • Sensitivity to light
  • Excessive tearing and discharge
  • Ulceration of the cornea
If you suspect that your cat is infected with Feline Herpes Keratitis, it is of utmost importance to seek medical help as soon as possible because the virus has the potential to severely damage the corneal tissue.


The diagnosis of Feline Herpes Keratitis is made based upon your cat's clinical history, the findings of a clinical exam, and the results of Rose Bengal, a vital stain, fluorescein stain or the Polymerase Chain Reaction (PCR) test. This entails doing a virus swab that is then submitted to a lab.

Conventional Treatments

  • Tetracycline (Terramycin) or chloramphenicol ophthalmic ointment are typically given. Although these do not affect the virus, they do eliminate secondary bacterial infections.

  • If the condition does not begin to resolve within two weeks, cats are usually put on trifluorothymidine (Viroptic) eye drops or Trifluridine eye ointment, which can irritate the eye.

Natural Treatments for Feline Herpes Keratitis

Because feline herpes keratitis is a viral infection, it is important to strengthen your pet's immune system with antioxidants and other nutrients.

The following vitamins, botanicals and other nutrients have been shown to fortify the immune system and/or nourish eye tissue:

Lysine is an amino acid that supports antibody, hormone and enzyme production. It also supports collagen formation and tissue repair. Lysine is thought to suppress blood arginine levels, thereby inhibiting herpes virus replication.

Vitamins A, C and E have antioxidant properties which fight free radicals that can damage the lens of the eye.

Astragalus is considered by many to be the most powerful immunity-boosting herb. Astragalus has antibacterial, anti-inflammatory and antiviral effects, and works by increasing the white blood cell production of your pet's own antiviral compounds alpha-and gamma-interferon, which help protect against viral invasion.

Bilberry extract (Vacciuium myritllus) derived from a fruit similar to the blueberry, contains active ingredients for eye health and proper vision. The berries are rich in the antioxidant anthocyanosides -- the red pigments that are beneficial in ophthalmology and vascular diseases. Nicknamed "the vision herb" bilberry has a substantial body of research that confirms its benefits for human eyes. This herb is very helpful to animals with early stage eye disorders, or for animals that have a genetic predisposition to eye problems.

Zinc is a mineral linked to good vision and may protect eye tissue from damaging light and inflammation. Zinc is found in healthy retinal tissue.

Lutein, a carotenoid found in dark, leafy greens, is also found in the retina of healthy eyes where it acts as a shield against harmful light and may help protect the eyes against damage from ultraviolet radiation.

Quercetin is a natural antioxidant bioflavonoid that protects cells from damage by free radicals.

Coenzyme Q-10, commonly called CoQ10, is a vitamin-like compound that acts as an antioxidant protecting cells against free radical damage. It exists in every cell of your pet's body, and it could not survive without it. CoQ10 is essential to the production of adenosine triphosphate (ATP), which produces energy within the cells and is the basis for normal functioning of all body systems and organs.  Besides being essential to heart health, CoQ10 enhances immune function, and is important to your pet's overall health.