Dog Squinting or Holding Eye Shut: Causes & What to Do

A dog who is squinting is usually showing eye pain. The medical term is blepharospasm, and it is a common reflex when the cornea, eyelids, or structures inside the eye are irritated. In many dogs, the problem is a corneal ulcer or abrasion caused by rough play, a scratch, plant material, dry eye, or an eyelid problem. Corneal ulcers are very painful, often cause tearing and redness, and are commonly confirmed with a fluorescein stain during the exam.

Other painful causes include a foreign body stuck under the eyelid, dry eye (keratoconjunctivitis sicca), uveitis (inflammation inside the eye), and glaucoma. Glaucoma is especially urgent because pressure inside the eye can rise quickly and threaten vision. Dogs with glaucoma may have a red eye, cloudy cornea, dilated pupil, reduced vision, or a firm-feeling eye. Uveitis can also cause marked pain, but it more often lowers eye pressure rather than raising it.

Some dogs squint because of eyelid or eyelash problems. Entropion causes the eyelid to roll inward so hair rubs on the cornea. Distichia and ectopic cilia are abnormal eyelashes that can irritate or even ulcerate the cornea. These problems may cause chronic tearing, intermittent squinting, and repeat ulcers until the underlying eyelid issue is addressed.

Less common but important causes include blunt trauma, chemical irritation, lens luxation, and orbital pain around the eye. Because several very different conditions can look similar at home, squinting should be treated as a symptom that needs an eye exam rather than something to guess at.

See your vet immediately if your dog has a red, cloudy, bulging, or suddenly blind eye, if the pupil looks unusually large, if there was trauma, or if the cornea looks soft, white, blue, or rapidly worsening. These signs raise concern for glaucoma, a deep or melting corneal ulcer, lens luxation, or a penetrating injury. These are vision-threatening problems and can become much harder to treat if care is delayed.

Same-day care is the safest plan for most dogs that are squinting, even if the eye still looks fairly normal. A simple corneal ulcer can be intensely painful and may deepen quickly if your dog rubs at it. Dogs with dry eye, uveitis, or a foreign body can also look only mildly affected at first. If there was possible shampoo, cleaner, or other irritant exposure, call your vet right away for guidance after flushing with sterile saline if available.

Home monitoring is only reasonable for a very brief period if the squinting is mild, your dog is otherwise comfortable, and the eye is not red, cloudy, swollen, or discharging colored material. Even then, if the squinting lasts more than a few hours, returns, or your dog paws at the eye, schedule an exam. Eye pain is one of those symptoms where early treatment often means a shorter, less intensive recovery.

Your vet will usually start with a focused eye exam and a few quick tests that provide a lot of information. A Schirmer tear test measures tear production and helps diagnose dry eye. A fluorescein stain checks for corneal ulcers or leaks in the cornea. Tonometry measures intraocular pressure and helps tell glaucoma from uveitis, since glaucoma raises pressure and uveitis often lowers it.

A magnified exam of the cornea, eyelids, anterior chamber, iris, and lens helps your vet look for foreign material, eyelid hairs rubbing the eye, corneal depth changes, inflammation, or lens movement. If an ulcer is deep, melting, infected, or not healing as expected, your vet may recommend corneal cytology or culture and more frequent rechecks.

Some dogs also need additional testing, such as blood work for systemic causes of uveitis or referral to a veterinary ophthalmologist. Referral is especially helpful for deep ulcers, indolent ulcers, glaucoma, lens luxation, or surgical eyelid problems. The goal is to identify whether the eye needs routine medical treatment, urgent pressure control, or a procedure to protect vision and comfort.

The most important home-care step is preventing your dog from rubbing the eye. Use the E-collar exactly as your vet recommends, even if your dog seems annoyed by it. A paw or a rub on the carpet can turn a small ulcer into a much deeper injury. Keep walks calm, avoid dusty or windy areas, and do not let your dog hang their head out of the car window while the eye is healing.

Give eye medications on schedule. Wash your hands first, avoid touching the bottle tip to the eye, and wait about 5 minutes between different eye drops unless your vet gives different instructions. If you are using both drops and ointment, drops usually go first and ointment goes last. Set alarms if the schedule is frequent. Eye medications often work only when they are given consistently.

Do not use human redness-relief drops, leftover pet eye medication, or steroid eye drops unless your vet specifically prescribed them for this episode. Steroids can seriously worsen some corneal ulcers. If there was possible chemical exposure, you can flush gently with sterile saline while arranging veterinary care, but do not keep trying home remedies if the eye remains painful. If the eye looks more red, more cloudy, more swollen, or your dog seems less able to see, contact your vet right away.