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Ocular FIP in Cats: Symptoms and Treatment

Feline Infectious Peritonitis (FIP) is a serious and often misunderstood disease in cats, caused by a mutated form of the feline coronavirus (FCoV). One of its less common but highly impactful manifestations is ocular FIP, where the virus affects the eyes, leading to inflammation, pain, and potential vision loss. Early detection and proper treatment are key to improving a cat’s prognosis.

Ocular FIP in Cats: Symptoms and Treatment

What is Ocular FIP?

Ocular FIP is a manifestation of the dry (non-effusive) form of FIP. It occurs when the mutated FCoV infects the eye tissues, particularly affecting the uveal tract (which includes the iris, ciliary body, and choroid). This immune-mediated inflammation results in visible ocular symptoms and discomfort for the affected cat.

Ocular FIP is often accompanied by neurological symptoms but can also present alone. It is more commonly seen in cats under two years of age or in immunocompromised animals.

Symptoms of Ocular FIP

Recognizing ocular symptoms early can help with quicker diagnosis and treatment. Common signs include:

  1. Anterior Uveitis

    • Inflammation of the front part of the eye (iris and ciliary body)

    • May cause the eye to appear cloudy or reddish

  2. Iris Color Changes

    • Discoloration or darkening of the iris

  3. Aqueous Flare

    • Light scattering in the anterior chamber of the eye due to increased protein

  4. Keratic Precipitates

    • White blood cell clumps are seen on the corneal endothelium

  5. Miosis (constricted pupils)

    • Often due to discomfort and inflammation

  6. Vision Loss or Impairment

    • Partial or complete blindness may occur

  7. Retinal Detachment or Hemorrhages

    • More advanced cases may show internal bleeding or retinal detachment

Diagnosis: How to Confirm Ocular FIP

Diagnosing ocular FIP is complex and often requires a multi-modal approach. Vets may use:

  • Ophthalmic Examination: Using slit lamp biomicroscopy and indirect ophthalmoscopy

  • Ocular Ultrasound: To assess internal eye structures

  • Fluorescein Staining: To rule out corneal ulcers

  • Tonometry: To measure intraocular pressure (usually low in uveitis)

  • Blood Tests: High globulin levels, anemia, and elevated protein levels

  • PCR Testing: On aqueous humor (fluid from the eye) to detect FCoV RNA

  • CSF Analysis: If neurological symptoms are also present

A definitive diagnosis of FIP remains challenging and often relies on a combination of clinical signs, laboratory findings, and exclusion of other diseases.

Treatment Approaches: Systemic + Local

1. Antiviral Treatment: EIDD-1931 (MolnuFIP)

MolnuFIP's EIDD-1931, a nucleoside analog, is one of the most promising antiviral treatments for ocular FIP. It inhibits viral replication and crosses the blood-ocular barrier, making it effective for eye involvement.

  • Dosage: Higher doses may be needed for ocular and neurological FIP

  • Duration: Typically 84 days of daily oral or injectable administration

  • Monitoring: Regular bloodwork and eye exams during treatment

2. Systemic Supportive Care

  • Anti-inflammatory medications: Prednisolone or NSAIDs may be used short term

  • Immune support: Supplements like lysine, vitamins C & E

  • Nutritional care: High-quality diet and hydration support

3. Topical/Ophthalmic Treatments

  • Steroid Eye Drops (e.g., prednisolone acetate): Reduce inflammation

  • Mydriatics (e.g., atropine): Relieve pain from uveitis

  • Antibiotic Drops: To prevent secondary bacterial infections

All ophthalmic medications should be prescribed and monitored by a veterinary ophthalmologist.

Monitoring Vision and Eye Health

Cats with ocular FIP need regular follow-ups with a vet or veterinary ophthalmologist:

  • Ophthalmic exams: Every 2–4 weeks during treatment

  • Imaging: If vision impairment progresses

  • Behavioral signs: Monitor for difficulty navigating, eye rubbing, or light sensitivity

Owners should maintain a log of observed symptoms and changes to help the vet assess progress and adjust treatment.

Real-World Outcomes and Recovery Stories

Though once considered fatal, many cats with ocular FIP now recover with early diagnosis and antiviral treatment like MolnuFIP.

  • Case Example: A 10-month-old kitten presenting with sudden vision loss and anterior uveitis was treated with EIDD-1931. Within 6 weeks, inflammation reduced significantly, and partial vision was restored by week 10.

  • Owner Testimonials: Many report improvements within the first month, including brighter eyes, more alert behavior, and regained sight in one or both eyes.

However, outcomes depend on early intervention, the cat’s immune response, and adherence to treatment protocols.

Conclusion

Ocular FIP is a serious but treatable condition in cats, especially with the emergence of antiviral therapies like EIDD-1931. Early recognition of symptoms such as uveitis, iris color changes, and vision impairment, combined with systemic and topical treatment, offers a real chance of recovery. With proper care, monitoring, and support, many cats can regain quality of life and even vision.

For more information or to explore antiviral options like MolnuFIP, visit our Treatment Page.

 
 
 
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