As happens with other animals, rabbits can suffer from a wide variety of ophthalmological pathologies, which can affect different eye structures. Knowing the main clinical signs associated with these pathologies is crucial to detect any eye problem early, act quickly and avoid complications.
Do you want to know the main eye diseases of rabbits? If so, feel free to join us in the next article on our site.
Dacryocystitis
Dacryocystitis is a very common eye disease in rabbits. It is an inflammation and infection of the system responsible for the drainage of tears, specifically the tear duct and cistern. The nasolacrimal duct is a channel that connects the eye with the nasal cavity, which allows the drainage of tears. In rabbits, this duct has a tortuous route, with several sudden narrowings that often lead to total or partial obstruction of the duct. As a consequence, the tear begins to accumulate, creating the ideal conditions for the development of an infection.
In general, this pathology is usually secondary to an underlying dental disease, although it can also be due to rhinitis, granulomas or, less frequently to primary duct infections.
The most obvious clinical sign in these rabbits is the presence of a seromucous or mucopurulent exudate in the inner corner of the eyeAlthough the symptoms allow the diagnosis of the process, it is necessary to carry out complementary tests (X-ray, CT, etc.) to determine the cause of dacryocystitis. In addition, it will be necessary to take a sample to perform a microbial culture and be able to establish a specific antibiotic treatment.
Treatment
Treatment of dacryocystitis in rabbits should include:
- Nasolacrimal duct lavage (flushing) with physiological saline twice a week. This helps remove accumulated exudates from the duct and restores the normal flow of tears.
- Antibiotic treatment: the microorganism isolated in the culture will be taken into account to establish a specific antibiotic therapy.
- Treatment of primary cause (if known).
Glaucoma
Glaucoma is a pathology characterized by the increase in intraocular pressure, which ends up producing the degeneration of the optic nerve and with it loss of vision.
In rabbits, glaucoma can be a process:
- Primary: due to a congenital defect of the iridocorneal angle that prevents the aqueous humor from draining correctly. As a consequence, aqueous humor accumulates inside the eye and increases intraocular pressure. It is the most common type of glaucoma in domestic rabbits.
- Secondary to other ocular pathologies: such as cataracts, uveitis, intraocular neoplasms, etc., which also alter the drainage of aqueous humor and they favor the increase of intraocular pressure.
Ocular signs that can be observed in rabbits with glaucoma are:
- Eye pain: Rabbits often show pain with apathy and depression, often scratching or rubbing their head on the side of the affected eye.
- Buphthalmia: Enlargement of the eye due to excess intraocular pressure.
- Diffuse corneal edema: opacity of the cornea.
- Mydriasis: pupil dilation.
- Vision loss.
The diagnosis is based on three points:
- Complete ophthalmological examination.
- Tonometry: consists of measuring intraocular pressure.
- Gonioscopy: consists of exploring the iridocorneal angle (point through which the aqueous humor drains) with an instrument called a gonioscope.
Treatment
The goal of glaucoma treatment is to maintain intraocular pressure at normal values to prevent damage to the optic nerve and loss of vision.
- In acute glaucomas: there is a chance of recovering the animal's vision, so emergency treatment should be instituted to reduce the Intraocular pressure. For this, eye drops with carbonic anhydrase inhibitors (such as dorzolamide), beta-adrenergic receptor blockers (such as timolol) or hypotensives (such as mannitol) can be used.
- In chronic glaucomas: blindness is irreversible, so therapy is only aimed at reducing eye pain through surgery as aesthetic as possible. Depending on the case, an enucleation can be performed (remove the eyeball and close the eyelid) or opt for a more aesthetic option, such as emptying the eyeball and placing an intraocular prosthesis.
Uveitis
Uveitis is another of the most common eye diseases in rabbits and consists of inflammation of the uvea, the layer vascular system of the eye composed of the iris, ciliary bodies, and choroid.
Although there are multiple causes capable of producing uveitis, in rabbits there are two that are especially frequent:
- Traumatic causes.
- Infectious causes: due to Encephalitozoon cuniculi (produces the so-called phacoclastic uveitis), Pasteurella spp. or Staphylococcus spp.
The most frequent signs in cases of uveitis are:
- Blepharospamus: eye closed due to ocular pain.
- Hyperemia: red eye.
- Epiphora: tearing.
- Miosis: pupillary contraction (not always produced).
- Diffuse corneal edema: opacity of the cornea.
- When the process progresses you can see hyphema (deposit of blood in the anterior chamber), hypopion (deposit of white blood cells in the anterior chamber) or cataracts(lens opacity).
The diagnosis of uveitis in rabbits is made by a complete ophthalmological examination, but it will also be important to perform a battery of complementary tests to find out the cause of uveitis (blood and urine tests, ultrasound and eye X-ray, etc.).
Treatment
The treatment plan should focus on three aspects:
- Treatment of the primary cause of uveitis: especially when there are infectious causes, which will require specific antibiotic or antiparasitic treatment.
- Inflammation control: using anti-inflammatory drugs (corticosteroids or NSAIDs), topical or systemic. It should be noted that treatment with corticosteroids is contraindicated when the cause is infectious.
- Ocular pain control: with tropicamide cycloplegic eye drops.
The prognosis fundamentally depends on the cause of the uveitis, so uveitis of traumatic origin have a much better prognosis than those of infectious origin.
Waterfalls
A cataract is a opacity of the lens which, depending on its size and degree of maturity, can produce different degrees of vision loss.
Your diagnosis requires:
- Pupil dilation with tropicamide to be able to explore the entire lens.
- Backlight scanning: Allows you to clearly observe the opacity of the lens.
- Ocular ultrasound and electroretinography: to confirm that the loss of vision is due to the cataract and not to another ocular disorder.
Treatment
The treatment is necessarily surgical since there is no medical treatment capable of eliminating the opacity of the lens. Specifically, the surgery of choice is phacoemulsification, which consists of removing the lens and replacing it with an intraocular lens.
The prognosis after surgery is very good, such that between 90-95% of rabbits recover their vision.
Conjunctivitis
Conjunctivitis is defined as inflammation of the conjunctiva, the mucous membrane that covers the back of the eyelids and the front of the eyeball.
There can be multiple causes of conjunctivitis in rabbits, some of the most relevant being:
- Bacterial infections: The rabbit's conjunctival sac contains physiological microbial flora that can become pathogenic under certain circumstances. The pathogen Staphylococcus aureus is frequently isolated from rabbit conjunctivitis.
- Viral infections: such as that caused by the myxomatosis virus, especially in unvaccinated rabbits.
- Parasitic infections: such as that caused by the microsporidium Encephalitozoon cuniculi.
- Dental disease: such as overgrowth of dental roots or dental abscesses.
- Foreign bodies: such as hay, straw, grass or seeds, which can stick to the eye and irritate the conjunctiva.
The most frequent signs of conjunctivitis in rabbits are:
- Conjunctival hyperemia: red eye.
- Chemosis: edema of the conjunctiva.
- Epiphora: tearing.
- Serous exudates, mucous or purulent.
- Conjunctival hyperplasia and follicle formation.
Treatment
The treatment of conjunctivitis will depend on the primary cause, so that antibiotics, antivirals or antiparasitics may be administered in case of infection, surgical treatments in cases of dental pathologies, etc.
Corneal ulcers
Corneal ulcers are also among the most common eye diseases in rabbits. The cornea is the outermost transparent layer of the eye, which covers the iris and frontally delimits the anterior chamber. As in other species, the rabbit cornea is made up of 4 layers: the outer epithelium, the stroma, Descemet's membrane, and the inner endothelium. When this structure suffers external aggression, a wound called a corneal ulcer is produced, which can affect one or more layers of the cornea. In rabbits, sores often occur as a result of fighting with other animals or rubbing their facesagainst cage bars or against abrasive materials (carpet, bedding, etc.).). However, they can also appear as a consequence of other pathologies, such as dry keratoconjunctivitis (or dry eye), entropion, buphthalmia, etc.
Depending on their depth, corneal ulcers are classified as:
- Superficial ulcers: Only the outer epithelium and the superficial layer of the stroma are affected.
- Deep ulcers: a significant part of the stroma is lost.
- Descemetocele: when they reach Descemet's membrane.
- Perforated ulcer: when the cornea is completely perforated and the iris protrudes through the wound.
The most common clinical signs of corneal ulcers in rabbits are:
- Epiphora: tearing.
- Blepharospasm: eye closed due to pain.
- Conjunctival hyperemia: red eye.
For the diagnosis it is necessary to carry out:
- A complete ophthalmologic examination: In addition to tissue loss, focal corneal edema may be seen. In chronic cases, it is possible to observe the formation of new vessels and cellular infiltration in the cornea.
- A fluorescein stain: this dye will delimit the corneal ulcer by attaching to the stroma, however, it must be taken into account that this This technique will not be effective in cases of very deep ulcers in which all the stroma has been lost (descemetocele or perforation).
Treatment
Treatment of corneal ulcers in rabbits depends on the cause, depth/extent, and severity:
- In case of superficial ulcers: administer an antibiotic eye dropBroad-spectrum (such as combinations of neomycin, polymyxin B, and gramicidin) to prevent infection and promote healing. In addition, a cycloplegic eye drop (such as tropicamide or cyclopentolate) should be given to reduce pain.
- In case of deep, complicated or infected ulcers: the frequency of administration of the antibiotic eye drops should be increased (every 1-2 hours) and must apply an autologous serum to stop the destruction of the corneal tissue. If the animal does not respond and the ulcer continues to progress despite medical treatment, surgical treatment may be necessary
In addition, an Elizabethan collar should be placed in either case to prevent the animal from self-traumating when scratching, as this could further complicate corneal damage.
As you can see, the different eye diseases of rabbits require veterinary treatment, so it is very important to go to your nearest center if you observe any of the symptoms mentioned.
