Spotlight: Main Eye Conditions Affecting Cats
The London Cat Clinic ( www.thelondoncatclinic.co.uk), which is set to open the UK’s first UK centre dedicated to treating eye conditions in cats in September, is highlighting the main eye conditions affecting felines in a bid to keep our pets’ eyes healthy.
Leading feline eye specialist, Dr Ursula Dietrich, who will run the clinic’s ophthalmology service, revealed: “Cats’ eyes have great visual acuity, as they are predators first and foremost. There are a number of eye conditions affecting cats, some of which are caused by the Feline Herpes Virus, which affects around 80% of all cats, some conditions specific to the brachycephalic or flat-faced breeds such as Persian or Burmese cats and injuries caused by other cats, or while roaming.”
Here, Ursula highlights the main problems affecting cats’ eyes, and how to recognise the signs and symptoms of these conditions.
A variety of eye conditions in the cat are linked to an infection with Feline Herpes Virus (FHV). The virus is very common and easily transmitted among large cat groups, such as catteries, multiple cat households and boarding facilities. Most cats get infected at a very early age after maternal antibodies have waned around 8-12 weeks. After an initial infection (often clinically manifest as an upper respiratory tract disease) the virus goes dormant. Stressful events will trigger re-activation of the virus causing ocular disease, such as conjunctivitis and corneal ulcerations.
There are four key, potentially very serious conditions when left untreated related to FHV, which are: conjunctivitis, corneal ulcerations, keratitis (inflammation of the cornea) and corneal sequestrum ('dead' area of the cornea):
Recurrent bouts of conjunctivitis are the most common symptoms of a herpes virus infection in younger cats. The cat may present with tearing, eye discharge and red, irritated eyes. The cat may also have an episode of sneezing during this active infection. The condition is often self-limiting and may recur from time to time.
2. Corneal ulcerations
Corneal ulcerations are a very common eye condition in cats and often linked to a recurrent herpes virus infection. If a herpes infection is suspected, anti-viral therapy is recommended either with topical drops/ointments or as an oral application. Other causes of ulcerations could be injuries due to sharp or blunt trauma, which could result in secondary infections and corneal damage. A corneal ulcer always requires immediate attention and frequent eye medications to prevent infection and to support the corneal healing.
Keratitis is an inflammation of the cornea. The cornea will become cloudy and is infiltrated by blood vessels, which may cover the entire surface of the eye. One of the causes might be an infection with the herpes virus causing an immune-mediated reaction to the virus deeper in the cornea. A very unique form of keratitis “eosinophilic keratitis” is seen in cats with white plaques appearing on the surface of the cornea. There is significant cloudiness and it may affect the entire cornea in advanced stages. It is believed to be an immune-mediated condition and can be treated with topical anti- inflammatory and immune-modulating medications. It requires long-term and often life- long treatment but in many cases, the cornea will become clear and transparent.
4. Corneal sequestrum
A corneal sequestrum is a ‘dead’ area of the eye and is easily detected as a brown/dark brown or black spot on the cornea, which causes ongoing discomfort and a significant corneal reaction in the cornea with cloudiness and blood vessel ingrowth. In very rare circumstances, a corneal sequestrum may slough off the corneal surface, but in most cases corneal surgery and removal of the sequestrum is recommended. Depending on the depth and extent of the corneal necrosis a grafting procedure may become necessary.
There are four additional non FHV related conditions affecting cats' eyes that are also potentially very serious, some of which are prevalent mainly in flat-faced felines:
5. Eye injuries
Cats (particularly if going outdoors or cats in multiple cat households) are prone to corneal or other ocular injuries. “Cat scratch” injuries are the most common reason for emergency referrals but other sharp objects (e.g. thorns) may also cause perforating corneal damage. In many cases, surgery is required to seal the corneal or scleral wound, which is performed under the operating microscope. This gives the ophthalmic surgeon a high magnification of the ocular structures and the necessary aid to place the sutures, which are usually as fine as a human hair. The animal is under general anaesthesia during this procedure and monitored by an anaesthesiologist or experienced theatre nurse.
Glaucoma is a condition where the intraocular pressure inside the eye rises above the normal level and which will cause blindness of the eye over time due to retinal and optic nerve damage. Primary glaucoma (there is no underlying ocular condition causing the rise in intraocular pressure) has been considered a rather rare condition in cats and is being investigated in some purebred cats, such as Burmese and Siamese cats. More often, glaucoma in the cat is secondary to an underlying ocular disease, such as chronic inflammation or undetected lens injury. However, because many cats do not show symptoms of pain, particularly in earlier stages, glaucoma in cats is often overlooked. Anti-glaucoma medications may help to lower the pressure inside the eye; but depending on the severity of the underlying condition and if vision is still present, the eye may need to be removed.
The eye will become cloudy and the iris will appear darker or more reddish-brown in colour. This condition requires intensive topical treatment with anti-inflammatory medications to prevent serious complications, such as glaucoma, which may lead to blindness and even loss of the eye.
8. Intraocular neoplasia
Intraocular neoplasia in cats may affect particularly the iris. Brown spots on the iris which grow bigger and darker over time could be indicative of diffuse iris melanoma. Unfortunately, there is no cure for this condition and the eye may need to be removed in advanced stages as the tumour will readily spread inside the eye and may also lead to secondary cancer.
For more information, including photos, please visit: https://www.thelondoncatclinic.co.uk/ophthalmology
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