The senses are an essential tool for survival in natural selection. Domesticated animals live longer than wild ones, thanks to the care of the owners, but this has a “flip side” - diseases, sometimes lifelong and irreversible. Blindness in dogs is a serious pet affliction and the death sentence of a stray animal. It is almost impossible to predict a congenital abnormality or its development, however, it is necessary to know and be able to interpret the signs of vision loss.
Causes of Dog Blindness
Any disease, trauma or developmental abnormality that completely or partially blocks light from entering the retina leads to blindness. The eye is a complex device, a fairly autonomous organ with its own protection tools. Given that eyeballs are directly related to the brain, there are three main causes of blindness:
- Nervous disorders.
- Pathology of the eyes.
The brain perceives information in the form of nerve impulses so that the dog can see, the following algorithm must occur:
- Rays of light hit the object and are reflected from it.
- Reflected rays of light pass through the cornea, the anterior chamber of the eye, the pupil and the vitreous.
- Refracted and scattered rays reach the retina - an organ consisting of receptors (rods and cones), which transform the light signal into a nerve impulse.
Note! In fact, the process of reproducing the image takes less than a second, while the brain manages to "weed out" the excess information.
How to detect blindness or decreased vision in a dog
A standard veterinary examination does not reveal most of the disorders that affect visual acuity. You may notice signs of vision loss while watching your pet in everyday life:
- The dog moves uncertainly, especially if the pieces of furniture are not in the same places.
- Going down or climbing stairs, the ward throws his paws high or stumbles.
- The pet refuses active games and aport offerings, eschews other dogs, especially those with which confrontations may arise.
- During walks, the animal most of the time keeps its head tilted to the ground.
- There may be problems with the perception of commands given by gestures.
- There is a concentrated look (the dog looks through objects).
One method to detect blindness in a dog is a test in a dark room. In a small room, several obstacles are placed, after which the light is turned off in the room. An animal caught in an unfamiliar environment will rely on scent and touch, and only then on vision. Watch whether the ward stumbles on obstacles or can avoid them. Turn on the light, if the dog does not see, it will follow the same route, the sighted animal will perk up noticeably and will behave more confidently.
Congenital blindness in dogs is a rare occurrence, diagnosed at the age of 6-8 weeks. Only a veterinarian-ophthalmologist can accurately determine blindness in puppies; on your own, you can conduct the following tests:
- A large piece of cotton wool is tied to a thread. At a time when the puppy is not busy with anything, it is necessary to stand in front of him and swing the cotton wool in the air. If you observe eye movement or a more pronounced reaction - the baby sees.
- Use a laser pointer or flashlight. Aim the beam toward the front legs of the pet and observe the reaction.
- Response to the threat - cover one eye of the animal with a bandage and make a sharp gesture with your hand in the direction of the dog's face. The ward should blink and dodge. Repeat the test with the other eye.
Important! Even the undisturbed vision of dogs is not particularly sharp. For orientation in space, the dog uses a sharp sense of smell and hearing, so vision tests should be carried out in complete silence and with odorless irritants.
Dog Blindness Diseases
Animals with visual impairment are not allowed until breeding, please note that when buying a puppy, you have the right to require a document confirming the health of both parents. Night blindness in dogs is a disease transmitted by inheritance, including through one or several generations. The course of the disease can be expressed in partial loss of vision in the light or in the dark, complete blindness from birth or due to the progression of the disease. A dog is born sick if both of its parents have a damaged gene - confirmed by a DNA test.
Increased intraocular pressure (glaucoma) is the most common cause of vision problems in young pets. The problem is that the disease proceeds covertly until the onset of a “critical moment”; often, sudden blindness in dogs is a consequence of glaucoma. Treatment of deviations depends on the root cause of the development of the disease, usually the veterinarian prescribes complex symptomatic treatment - drugs that reduce blood pressure, increase blood flow, and prevent blood clots.
Detachment or atrophy of the retina due to hormonal imbalance and hyperactivity of the thyroid gland occurs with diabetes mellitus or adrenal dysfunction. The process of atrophy can be stopped, but it is impossible to restore lost vision without surgical intervention.
Neoplasms in the brain or eyeballs exert direct physical pressure on the blood vessels and nerve endings. Blindness can be a symptom or complication of a nervous disorder due to damage to parts of the brain. Often, vision loss is a temporary and reversible disorder. For example, a dog may partially go blind after epilepsy or stroke, but with proper treatment, vision can be restored.
Cataracts are considered a disease of older dogs, however, they can develop after an injury to the cornea or anterior eye chamber, for example, from a cat’s claw. The disease is accompanied by a clouding of the lens, which refracts and scatters light rays. Cataracts develops gradually, most often, irreversibly. The only cure option is a surgical lens replacement, but such operations are rare.