Retinian Athrophy progressive (Pra) – Pets Stuff

Author: Veterinary Doctor – Lia Ion.

The atrophy of the progressive retina includes a group of conditions that can be found in different breeds of dogs, the most common found in the United States in the country in Golden/Labrador Retriever, Cocker Spaniel, German Brac, but also for their tea. It can influence cats in the Persian breed, but also those of the common breed. Progressive retinal atrophy has a genetic component, which is why it is recommended that affected patients are not used in assembly.

The disease affects the photocercers (cells with cones and sticks), those who capture light and help form the image in the retina. The cells with sticks, those that deal with night vision and are more numerous in dogs and cats, are more frequently affected than cones cells. Therefore, the vision in seeds -grave or night is the first to suffer.

Pra is a bilateral condition, changes that occur equally in the two eyes. There are different forms of illness, which causes an abnormal development of the photoreceptors, which leads to the early use of clinical signs and a degenerative form, which appears later in the life of patients.

In the initial form, patients show visual acuity for 4-6 months, can be completely blind at the age of 6-12 months. In degenerative form, the first signs of visual acuity reduction can occur at the age of 2, 6 years, sometimes even at 10 years.

Initially, the owners can see the dog’s refusal to lower the stairs or go out when it is dark. As the disease advances, affected individuals begin to affect objects, visual acuity is reduced or even absent during the day. The best changes are better observed when patients are brought to an unknown place.

From a clinical point of view, the condition is characterized by the appearance of mydriasis (dilated pupil), with the absence of the pupillary reflection (the pupil does not tighten the use of a stimulus of light). The owners can see a more intense glow of the eyes, due to the increase in reflectivity in the retina. The veterinarian can use a specialized device, called Irisvet, with which to evaluate the reply of the pupil to the red light (light with a wavelength of 630 Nm). If there is a impairment of the retina, the pupil does not hold because of the stimulation with this type of light. Furthermore, with the help of the Oftalmoscope, hyperreflectivity is observed in the lucidum wallpaper (the upper part of the bottom of the eye) and a decrease until the absence of the retinal vessels.

Fig. 1. Exam with Irisvet. It is observed that Miosis gets due to stimulation with red light.

(Labrador, male, 3 years old)

Fig 2. Exam with Irisvet. Negative response to the stimulation of red light, the pupil remains in the mydriasis.

(Heatwave, female, 6 years old)

Fig. 3. Exam with panoptic ophthalmoscope

To certainly evaluate the degree of diseases of retinal cones and sticks, the ophthalmologist can use electroretinography, a diagnostic method that records electric stimuli from the retina. This examination provides for sedation or even general anesthesia and is particularly recommended in the situation in which the patient also presents the cataract and must be established if it is a candidate for the functioning of the facehemulting (specific surgery for the removal of the crystalline with the cataract).

The disease has a serious prognosis, all patients affected eventually reach blindness. It can be attempted to administer antioxidant drugs specially designed for veterinary ophthalmological use, which will cause a less faster evolution than the disease. There is also a genetic test with which individuals of the genes are detected leading to the appearance of the atrophy of the progressive retina. It is recommended to be performed in the predisposed breeds, the patients concerned can therefore be removed from the breeding.

The owners should know that their pets can do very well and if they do not see, in the dog and in the cat the smell and hearing are better developed than the sight. These patients should be helped by keeping a well -known environment (if it is possible to live in the same house or courtyard, not to change the place of furniture or other objects) and when they are brought to unknown places to be kept on a leash and smell new things.