SYMPTOM
Corneal cloudiness
Owners may observe corneal cloudiness in their pet.
Various conditions
This symptom can occur in multiple conditions and warrants further assessment.
Corneal Ulceration and Trauma
A break in the corneal surface allows fluid to seep into the stroma, producing a hazy or white patch centred on the site of injury. Triggers include foreign bodies, self-trauma, and eyelid conformation problems such as entropion in Shar Peis and Bulldogs. In cats, herpesvirus infection is a frequent underlying driver of recurrent ulceration and associated cloudiness.
Raised Intraocular Pressure (Glaucoma)
Elevated pressure within the eye overwhelms the corneal endothelium's ability to pump fluid out of the stroma, giving the whole cornea a diffuse blue-grey haze rather than a localised patch. Primary glaucoma has recognised breed patterns in dogs, including Cocker Spaniels and Basset Hounds, while secondary glaucoma can follow uveitis or lens luxation in either species.
Immune-Mediated Keratitis
Chronic superficial keratitis (pannus), most recognised in German Shepherds, involves pigmented and vascular tissue spreading across the cornea from the outer edge inward. Eosinophilic keratitis in cats produces raised pink-white plaques from eosinophil infiltration and is often linked to underlying herpesvirus. Both processes cloud the cornea gradually rather than acutely.
Corneal Sequestrum
Specific to cats, a sequestrum is an area of dead corneal tissue that turns brown or black and sits within a zone of surrounding oedema. It is seen more often in brachycephalic breeds such as Persians and Himalayans, usually following chronic irritation, breed conformation, or previous herpesvirus keratitis.
Age-Related Lens Change (Nuclear Sclerosis)
From around eight years of age, a normal hardening of the lens fibres gives the pupil a hazy blue-grey appearance that owners often mistake for corneal cloudiness. Vision remains largely unaffected and the corneal surface stays smooth and clear, distinguishing this ageing change from true corneal disease.
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
Corneal Ulcers
Oedema and cellular infiltration of the damaged cornea create visible opacity.
Glaucoma
Corneal oedema from elevated pressure creates characteristic haziness.
Corneal Sequestrum in Cats
The sequestrum itself appears as a dark, opaque patch on the surface of the cornea.
Eosinophilic Keratitis in Cats
Pink to white plaques build up on the corneal surface in this condition, giving the eye a cloudy or hazy look.
Pannus (Chronic Superficial Keratitis)
The abnormal tissue growth across the cornea in pannus produces a grey-pink haze that thickens over months.
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