By Dr. Woody Dudley, DVM
Early Detection and Treatment of commonly seen eye conditions in our pets can prevent Blindness and Enucleation (surgery to remove the eye).
Vision and pain free eyes are so important to the quality of life in our pets. Many eye conditions can be prevented or delayed with eye screening.
Eye screening tests:
- Intraocular Pressure with Tonometry – Elevated pressure inside the eye is seen with Glaucoma. Low pressures are seen with inflammation of the inside of the eye, Uveitis. Increasing age late in life can also cause low pressure inside the eye.
- Schirmer Tear Test – This is a paper test that measures tears produced by the eye. Tears are important to protect the surface of the eye.
- Eye Staining – Stains such as Flourescein and Rose Bengal are used to visualize defects on the surface of the eye such as corneal ulcers.
- Slit lamp – Slit lamp provides magnification and a thin beam of light to detect problems in the anterior chamber, lens defects such as cataracts, and small defects on the cornea or surface of the eye.
- Ocular Ultrasound – Ultrasound uses sound waves to see detached retinas, defects inside the eyes, and masses behind the eye such as tumors or abcesses.
Health Conditions we can detect with eye screening:
Glaucoma – Glaucoma is a build up of pressure in the anterior chamber, the part of the eye in front of the lens. In dogs and cats it is almost always due to a blockage of the aqueous humor produced by the ciliary body as this fluid leaves the eye, much as a plugged drain hole in a sink prevents water to leave when the Fawcett is turned on. The pressure that builds up in the eye compresses the retina, the sensory area on the back of the eye, which is involved in vision and leads to damage and vision loss. The pressure stretches the eye and causes pain as well. If the pressure is not reduced in a timely manner, permanent blindness and long term pain can occur. There are many surgeries and treatments available through an eye specialist. Many of these cases will end up having the eye surgically removed to end the pain and long term medical treatment.
Complications of Glaucoma: Blindness, pain and inflammation, blood shot eyes, swollen eyes, fixed dilated pupils, rubbing eyes, Surgery or Enucleation.
Uveitis – Inflammation can occur inside the eye. You may see a blood shot eye or squinting with this. This can occur when the inside of the eye is affected by other systemic illnesses. Many of these may have an unknown cause. It is important that these cases are treated in a timely fashion because Uveitis can lead to Glaucoma and the need for eye removal. Certain dog breeds are more likely to develop Uveitis such as Golden Retrievers.
Complications of Uveitis: Pain and Inflammation, Blood Shot eyes, Rubbing Eyes, one pupil more constricted than the other, cloudy eyes, blindness, Glaucoma, Enucleation.
Cataracts – Cataracts are an opacity of the lens which blocks vision. Cataracts occur as our pets age. They can be due to certain systemic illnesses such as Diabetes. Certain breeds have a higher risk of cataracts. Cataracts need to be diagnosed and treated early to prevent lens induced uveitis. As a cataract gets larger and matures, our pets’ cataracts become inflamed by the pet’s own immune system. This inflammation of the inside of the eye causes discomfort which over time can lead to glaucoma. When glaucoma from cataracts becomes advanced many clients opt to have the eye removed rather than long term eye treatment options.
Complications of Cataracts: Cloudy Eyes, Blindness, Lens Luxation, Pain and Inflammation, Rubbing Eyes, Blood Shot Eyes, Glaucoma, Surgery or Enucleation.
Dry Eyes (Keratoconjunctivitis Sicca) – Just as in the case of humans, many of our pets produce less tears as they age. The cause is thought to be due to the body’s immune system adversely affecting the tear glands. The flat faced breeds with bulging eyes have this problem at higher frequency. The reduction in tears causes problems with the outer surface of the eye, the cornea, and infections and discharges that come and go.
Complications of Dry Eyes: Blood shot eyes, Black Pigment on the surface of the eyes which reduces vision, ulcers of the cornea (missing and damaged layers), rubbing the eyes, squinting, thick eye discharges, blindness.
Corneal Ulcers – Corneal ulcers are a painful loss of the outer layers of the cornea caused by many different things including trauma, irritants, viruses, bacteria, fungus, self-trauma from rubbing the eyes, and dry eyes. Staining tests, green or red, will help to see these. Corneal Ulcers will need aggressive treatment to prevent a rupture of the eye and scarring.
Complications of Corneal Ulcers: Pain, Eyeball Rupture, rubbing the eye, blood shot eye, discharges in the eye, permanent scar or blind spot, surgery.
Herpes in cats – According to Veterinary experts, greater than 80-90% of cats have been exposed to the virus Herpes. Many of these cats are carrying this virus in their bodies for their entire life. Herpes causes a painful infection and ulcerations to the surface of the eye. Many people have had Chicken Pox when they were young. Chicken Pox is caused by a Herpes virus. This virus stays dormant in the body and later in life many of these same people will develop Shingles from the same Herpes virus that caused the Chicken Pox. In a similar way, many cats have had a respiratory and eye infections caused by Herpes when they were kittens. The Herpes virus becomes dormant in the nerve tissue of the cat and later in life many of these same cats develop recurrent eye infections caused by Herpes. Fortunately Herpes in cats is not transmissible to humans.
Complications of Herpes in Cats: Squinting, eye discharge, rubbing eyes, winking, corneal ulcers, cloudy white or pink surface of the eye, scarring of eye surface or third eyelid, dry eyes, long term antiviral treatment for recurrent infections.