SYMPTOM
Enlarged eye
Owners may observe enlarged eye in their pet.
Various conditions
This symptom can occur in multiple conditions and warrants further assessment.
Why timing matters
Early observation
Early recognition allows prompt assessment and intervention if needed.
Later presentation
Persistent or worsening signs may indicate progression requiring attention.
The significance of this symptom depends on its context, duration, and associated findings.
Conditions commonly associated
Glaucoma
Chronic pressure elevation stretches the globe, causing visible enlargement (buphthalmos).
Feline Herpesvirus (FHV-1)
Feline herpesvirus infection can cause inflammation of the conjunctiva and other eye structures, leading to swelling that may make the eye appear enlarged. This ocular involvement often occurs alongside other upper respiratory signs such as sneezing and nasal discharge.
Feline Calicivirus
Feline calicivirus infection may cause conjunctivitis and periocular inflammation, which can result in visible swelling around the eye. The ocular changes typically occur as part of a broader respiratory illness affecting the nose, mouth, and airways.
Hyperthyroidism in Cats
Hyperthyroidism in cats can lead to elevated blood pressure, which in turn may cause bleeding or fluid accumulation within or behind the eye, sometimes resulting in visible enlargement. Retinal changes and other ocular complications are recognised sequelae of poorly controlled hypertension in affected cats.
Chronic Kidney Disease in Cats
Chronic kidney disease in cats often leads to systemic hypertension, which can cause haemorrhage or oedema within the eye or orbit, occasionally manifesting as apparent enlargement. Hypertensive ocular damage is a well-recognised complication in cats with advanced or unmanaged renal disease.
When to explore further
When the symptom is persistent or worsening
When other signs are present alongside
When daily activities or quality of life are affected
When there is uncertainty about the cause
Noting when this symptom occurs, any triggers, and how it changes over time can provide useful information for veterinary discussions.
Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS