All you wanted to know about cataract in dogs
Cataract in dogs is a disease that causes the lens of the eye to become cloudy and causes visual impairment. Severe cases of cataracts can lead to blindness, so it is important to detect and treat the disease before it progresses.
Types of Cataracts in dogs
Cataract is a condition in which a portion or the entirety of the normally clear lens in the eye becomes cloudy and white. It is believed to be caused by the degeneration of the proteins that form the lens, causing it to become opaque.
Cataracts in dogs are classified into four categories according to the degree of progression as follows
- Early cataract There are no symptoms, and the level of lens degeneration cannot be seen without an ophthalmic microscope.
- Immature cataract A condition in which part of the lens becomes cloudy, but there are no symptoms of visual impairment.
- Mature Cataract A condition in which the entire lens is completely cloudy, resulting in visual impairment.
- Hypermature cataract A condition in which the lens proteins have melted. In many cases, this condition is accompanied by inflammation in the eye.
Causes of cataract in dogs
- Aging Age-related cataracts Implies the gradual whitening of the eyes as a dog gets older. In veterinary medicine, it is necessary to differentiate it from lens nuclear sclerosis, which will be mentioned later. Age-related cataracts, which are thought to be mainly caused by aging, are most seen in dogs aged six and older.
- Inheritance In general, many owners believe that cataracts develop in older dogs, but some dogs are already showing cataracts at the time of their first vaccination, and others develop cataracts by the time they are two years old. These “juvenile or young adult cataracts” are thought to be caused by an inborn failure of the lens to be properly produced in the fetal stage, or by an inability of the metabolic functions within the lens to function properly early in life, resulting in a cloudy lens.
- Uveitis In dogs Inflammation of the uvea, the tissue surrounding the lens, can affect the lens' metabolism and cause it to fail to metabolize properly, resulting in the development of cataracts. Uveitis, which is an inflammation of the uvea of the eye, is another cause of cataracts. In some cases, however, it is not clear whether uveitis or cataracts develop first.
- Progressive Retinal Atrophy in Dogs (Hereditary Retinopathy in Dogs) Progressive retinal atrophy in dogs is an inherited disease in which the retina at the back of the eye gradually atrophies. As the disease progresses, cataracts may develop.
- Trauma Cataracts They may develop if the eye is scratched by a cat, or if the eye is injured in an accident.
- Effects of radiation The crystalline lens is susceptible to damage from radiation, so cataracts may develop some time after radiation therapy to the head or nose, where the eye is exposed to radiation. In addition, ultraviolet rays are thought to be one of the causes of cataracts in humans. When exposed to ultraviolet rays, reactive oxygen species (ROS) are produced in the body, which damage cells and cause aging. At present, however, it is not known for certain whether or not ultraviolet rays cause cataracts in dogs.
- Toxic substances Poisoning with chemicals such as naphthalene and dinitrophenol can also cause cataracts. Naphthalene was used in the past as a mothballing agent for clothing. Dinitrophenol is an industrial preservative.
- Complications of underlying diseases Cataracts can develop from underlying systemic diseases such as diabetes and low calcium crystals.
- Diabetes (diabetes mellitus) As diabetes progresses, cataracts may develop because the metabolism in the lens does not work properly. The speed at which the cataract progresses depends on the severity of the diabetes.
- Hypocalcemia A drop in the level of calcium in the blood causes changes in the metabolism of the lens, which may lead to the development of cataracts.
Treatment for cataract in dogs
- Medical Treatment (Eye Drops) Unfortunately, there is still no treatment that can restore the clarity to the cloudy white lens caused by a cataract. When age-related cataracts are first detected, eye drops are used to control the progression of the disease. For post-mature cataracts, anti-inflammatory drugs (non-steroidal and steroidal) are used as symptomatic treatment. In any case, eye drops, along with regular examinations and visits to the doctor, can slow down the progression of cataracts, delay blindness, and treat uveitis resulting from cataracts.
- Surgical treatment (surgery) Cataract surgery for dogs is used to make the lens that has developed a cataract transparent so that light can reach the retina. The “lens phacoemulsification and aspiration technique” used in the treatment of canine cataracts is a surgical procedure in which high-frequency vibrations are used to break up and suck out the cloudy white lens, and an artificial lens is implanted where the lens used to be. Several days of hospitalization are required. After the surgery, the dog needs to undergo lifelong treatment with eye drops and regular visits to the hospital for check-ups and examinations.
Prevention of cataract in dogs
Unfortunately, there is no established way to prevent cataracts yet. If your dog has diabetes and has not yet developed cataracts, the first thing you should do is to treat his diabetes well to manage his blood sugar levels so that it does not worsen. Also, if your dog has uveitis or any other disease that can cause cataracts, it is important to treat it properly. Some people purchase expensive supplements on the Internet to prevent cataracts, but there are currently no effective supplements that have been shown to be medically effective in treating cataracts in dogs.