SYMPTOM
Eye squinting
Owners may observe eye squinting in their pet.
Various conditions
This symptom can occur in multiple conditions and warrants further assessment.
Conjunctivitis
Inflammation of the pink membrane lining the eyelids and covering part of the eye makes blinking uncomfortable, prompting a narrowed or held-shut eyelid. In cats this is frequently linked to feline herpesvirus, while in dogs bacterial, viral or allergic causes are all recognised, with redness and discharge usually accompanying the squinting.
Eyelid Conformation Abnormalities (Entropion or Ectropion)
Inward rolling of the eyelid margin (entropion) causes the surrounding hair to brush continuously against the surface of the eye and is a genuinely painful cause of squinting. Outward rolling (ectropion) is not painful in itself, but the poorly protected eye it leaves behind is more exposed to dust, drying and secondary conjunctivitis, which can in turn lead to some squinting. Entropion is strongly breed-associated, seen more often in Shar Peis, Chow Chows, Bulldogs and Cocker Spaniels, and in British Shorthair and Persian cats, and tends to appear from a young age rather than developing suddenly.
Foreign Body or Eyelash Disorders
Grass seeds, dust or other debris trapped under the eyelid, or eyelashes growing in an abnormal position and rubbing against the cornea, produce persistent mechanical irritation. Affected animals often paw at the eye or hold it shut more tightly than would be expected from surface redness alone.
Uveitis
Inflammation within the eye itself, affecting the iris and surrounding structures, causes deep ocular pain and sensitivity to light that leads to sustained squinting rather than a brief blink response. It can arise on its own or reflect an underlying process elsewhere in the body.
Minor Trauma or Corneal Abrasion
A superficial scratch from play, grooming, or contact with vegetation can irritate the surface of the eye enough to trigger reflex squinting even where the injury itself is minor and self-limiting. Cats and dogs living alongside other pets that play roughly are particularly prone to this kind of minor surface injury.
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
Squinting reflects pain from the exposed corneal nerve endings in ulcerated tissue.
Glaucoma
Pain from pressure elevation causes squinting and reluctance to keep the eye open.
Uveitis
Inflammation inside the eye is painful and triggers reflex closing of the eyelids to protect the eye from light and further irritation.
Entropion
An inward-rolled eyelid causes hair to continually rub against the cornea, and the resulting irritation makes the pet keep the eye partly or fully closed.
Conjunctivitis
Inflammation of the membrane covering the eye causes discomfort and light sensitivity, leading the pet to squint.
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