What is Progressive Retinal Degeneration?
Progressive retinal degeneration is a rare condition in the United States, but has been known to affect purebred cats including the Siamese, Persian, and the Abyssinian. The American curl feline, Tonkenese, American wirehair, Bengal cat, Oriental Shorthair and the Javanese/Balinese cat breeds have also held reports of contracting PRA, but are a lower risk.
Progressive retinal degeneration is characterized by a progressive degeneration of the retina, or photoreceptors (rods and cones in the retina) within the eye that aid in the ability to see. A healthy feline’s photoreceptors will fully develop at roughly eight weeks of age, giving the kitten the ability to see. However, a kitten affected with the mutated gene of progressive retinal degeneration will develop photoreceptors at the same age as a healthy feline, but they will degenerate with age. The degeneration process of the retina is slow occurring, but will often lead to total blindness as early as age three and as late as age five.
Symptoms of Progressive Retinal Degeneration in Cats
A feline with progressive retinal degeneration will progressively lose the ability to see and may become more cautious about her/his surroundings. The feline may take more time to assess a situation, such as walking into a room and meeting new people or other pets. The feline may bump into objects around the house or move slowly in order to identify the space in which she/he is occupying. Additional symptoms of progressive retinal degeneration a pet owner may note include:
- Pupil dilation
- Nervousness with other pets/animals
- Visual deflect at night
- Increased tapetal reflex that can be seen through the pupil
Causes of Progressive Retinal Degeneration in Cats
Progressive retinal degeneration in cats is an inherited, autosomal recessive disorder, which requires two copies of the mutated DNA to affect the offspring. Meaning, if only one parent possesses the gene, the infant will not be affected by PRA. However, if both parents possess progressive retinal degeneration genetics, the kitten will be born with PRA compromised DNA.
Progressive retinal degeneration itself is caused by a single nucleotide mutation of the gene known as CEP290, which produces a defective cellular protein. The cellular defect inflicts the fetus during development, targeting the retina’s rods and cones, which reflect light-- providing the ability to see.
Diagnosis of Progressive Retinal Degeneration in Cats
A differential diagnosis, which is the act of testing and excluding possible causes of the feline’s symptoms, is the likely method your veterinarian will take to diagnose progressive retinal degeneration. The doctor will begin the diagnostic process by reviewing your cat’s medical history and conducting a physical examination. Upon physical examination, your vet will determine which ophthalmic tests he/she should conduct to locate the problem. Common ophthalmic examinations performed to detect progressive retinal degeneration include:
- Tonometry (measurement of intraocular pressure)
- Schirmer test (evaluate tear production)
- Fluorescein staining to detect eye trauma
- Pupillary light reflex test (the act of placing light in the eye to observe dilation and contractions of the eye’s pupil)
Progressive retinal degeneration itself can be detected through an electroretinogram test. Often conducted by a veterinary ophthalmologist, an electroretinogram uses flashes of light to evaluate the functionality of the eye’s photoreceptor cells during stimulation. A confirmed diagnosis of progressive retinal degeneration is then made when the results come back as abnormal, meaning the retina is diseased and unresponsive.
Treatment of Progressive Retinal Degeneration in Cats
Progressive retinal degeneration has no available treatment to cure, slow, or prevent the degeneration of the retina. The degeneration process is occurring due to mutated DNA, which cannot be readily accessed as this is the feline’s genetic makeup.
The veterinarian may advise that you have the affected cat spayed or neutered to prevent passing the progressive retinal degeneration gene on to offspring. Progressive retinal degeneration in cats leads to blindness, but a blind cat can have a better quality of life if accommodated by the pet owner. Talk to your veterinarian about the best way to aid a feline who is losing the ability to see.
Recovery of Progressive Retinal Degeneration in Cats
Progressive retinal degeneration in cats can be tested with a simple cheek swab and laboratory examination. Feline breeders who enter Siamese, Persian or Abyssinian felines into their breeding program should test cats prior to breeding. Any feline with a positive PRA test result should be spayed or neutered to prevent further generations from progressive retinal degeneration.
Progressive Retinal Degeneration Questions and Advice from Veterinary Professionals
My 3 years cat was treated with enrofloxacin for 14 days, from day one he showed dilated pupils in both eyes ..
Please help.. dilated pupil's of cat after enrofloxacin
2 days ago
Dear Dr. Shailen,,
I hope my email finds you well and that you can advise me in any possible way how to help my cat (Sashu) in not fully losing his sight
Sashu has suffered from intestinal inflammation due to food allergy, I followed up with his vet that treated him twice with Prednisolone, Metronidazole, and Antibiotic that was changed in each time of treatment.
while taking his second trial of treatment, he got Bronchitis suddenly, contacted his vet that told me to bring him tomorrow due to he got his last shot of antibiotic in that weekend and to bring him on a regular day... but in the night his breathing became so hard and I took him to another vet that opens as an emergency, they started to give him:
Enrofloxacin 5% 1 ml every 48 hours, 7 injections
and Methylprednisolone 0.1 ml, 3 injections within the 2 weeks in addition to antihistamine
From day one I have reported to the vet who is treating him that he has a very large dilated pupils, it reflects alot of green light in the full light and in the dark, also his pupil responds to the light but not as usual, it only got smaller to the half only, and respond better while explored to sunlight and natural light, he can't see very well, we feel he can see from far away but from near distances he can't (he got scared if we touch him as if he can't see someone near him), he spends alot of time in isolated dark places or watching birds on the window.
His vet answers me that it's normal, be patient and give him time to recover, but on the 6th shot I insisted to know the cause, that's when he told me it's because of his stuffed nose. I knew this is not as much of a scientific answer so I searched more to find that Enrofloxacin can cause severe side effects to cat's eye ..
I don't know what to do .. it's very painful to see him like this, In my country, there is no vet specialized in eyes, and his body is weak due to cortisone treatment, I'm afraid to lose him
Please help me how can I preserve/rescue the remaining part of his vision.
Thank you so much for your response .. I really wish Sashu can maintain some degree of vision..
Add a comment to Sashu's experience
Was this experience helpful?