Feline red eye: when to refer and what to watch for 

Specialist advice for vets from Clarity Referrals – Veterinary ophthalmologist in Dorset

Red eye in cats is a frequent yet deceptively complex presentation in veterinary practice. From viral conjunctivitis to uveitis and glaucoma, many feline eye conditions share overlapping signs but have very different outcomes if not promptly diagnosed and treated.

Our specialist ophthalmologist, James Histed, provides expert support for feline eye disease across the South West from our Sherborne-based practice.  His practical guide offers tips to help general practitioners manage red eye cases and learn how to recognise the signs that advanced investigation or surgical care may be necessary.

Common causes of red eye in cats

The term “red eye” refers to conjunctival hyperaemia, episcleral injection or visible inflammation in or around the globe. Key causes include:

  • Feline herpesvirus (FHV-1) – causing conjunctivitis, dendritic ulcers or stromal keratitis
  • Eosinophilic keratitis – immune mediated and often misdiagnosed as infection
  • Anterior uveitis – linked to FIP, toxoplasmosis, lymphoma or idiopathic inflammation
  • Glaucoma – often secondary and easily missed in cats
  • Corneal ulceration – especially chronic or non-healing ulcers
  • Intraocular tumours – presenting as a red, painful or cloudy eye

These conditions often look similar early on, making correct diagnosis essential to prevent permanent vision loss.

Feline anterior uveitis – lymphoma in this case

What to do in first-opinion practice

Early recognition and appropriate diagnostic steps help guide decision-making. A thorough feline ophthalmic exam should include:

  • Fluorescein staining – to check for corneal ulceration
  • Tonometry – essential to distinguish uveitis (↓IOP) from glaucoma (↑IOP)
  • PLRs and menace testing – to assess vision and pupil symmetry
  • Direct or indirect ophthalmoscopy – to examine the posterior segment
  • Schirmer tear test – especially in chronic conjunctivitis or keratitis

Always assess both eyes and take a full systemic history. Remember, cats may show few clinical signs even with serious intraocular disease.

A slit-lamp (or even the small line on a direct ophthalmoscope) is perfect for assessing aqueous flare

When to refer a feline red eye case

Some red eye presentations can be managed in general practice. However, the following situations warrant early referral to a veterinary ophthalmologist:

  • Non-healing or melting corneal ulcers
  • Suspected herpetic or eosinophilic keratitis
  • Anterior uveitis with no clear cause
  • Suspected glaucoma or unexplained vision loss
  • Intraocular masses, buphthalmos or chronic ocular discharge
  • Refractory or recurrent inflammation despite standard therapy

Early referral to a specialist ophthalmologist allows for diagnostics such as cytology, culture and sensitivity, slit-lamp examination and, in some cases, surgical management (e.g. corneal grafts or enucleation if required).

Dental microbrushes make perfect tools for corneal and conjunctival cytology

How Clarity Referrals can help

Located in Sherborne, we welcome feline ophthalmic referrals from across Dorset, Somerset, Wiltshire, Devon and beyond. Our practice is designed to be a calm environment with a cat-friendly waiting area and dedicated ward for feline patients. All cases are seen by James Histed, RCVS and ACVO-recognised Specialist in Veterinary Ophthalmology.

We offer:

  • Detailed diagnosis using advanced ophthalmic tools
  • Tailored medical and surgical treatment plans
  • Transparent communication with both referring vets and owners
  • Timely appointments for urgent or vision-threatening cases

Need advice or to refer a case?

We’re happy to provide free advice to referring vets about red eye cases or to help you decide when referral is appropriate.

📧 hello@clarityreferrals.com

📞 01935 677892

🌐 https://clarityreferrals.co.uk