Ophthalmic (eye) emergencies require fast diagnosis. Therapy must be appropriate and often aggressive to save the animal’s vision.
Traumatic proptosis is a bulging of the eye out of the bony socket (orbit) caused by injury. It may follow blunt trauma (such as being hit by a car or attacked by another animal), which dislodges the eyeball from the orbit. Eyelid spasms prevent the eyeball from returning to its proper position. Then, bleeding and swelling push the eye further from the orbit. The eye becomes dry, and vision may worsen or fail.
Treatment involves surgically replacing the eye into the socket. Stitches and stents placed during the surgery are removed when a brisk blink reflex returns (usually 7 to 21 days). Potential complications include corneal tears, optic nerve damage, vision loss, muscle injury, inflammation, and infection. Loss of vision is common and removal of the eye (enucleation) may be recommended.
Bleeding in the Eye
If trauma damages the blood vessels in the eye, intraocular bleeding occurs. Proptosis may also be present. Parts of the eye may swell, or the animal may not be able to close the eyelids.
Therapy usually includes topical and systemic (whole body) antibiotics, corticosteroids, or other drugs. The upper and lower eyelids may need to be sewn together to protect the cornea until a brisk blink reflex returns. Glaucoma is a potential complication.
Foreign Objects in the Eye
Foreign objects in the eye are common in dogs, cats, and horses. These can be organic material, sand, metal fragments, glass shards, or other small objects. Redness, tearing, and swelling of the eye are common. The eyelids may spasm, and the animal may rub the affected eye. The animal may need to be sedated for examination and treatment. Foreign objects can usually be removed by flushing the eye with saline solution or using small forceps that look like tweezers. Sutures may be used to close a wound, if present. Topical and systemic (whole body) antibiotics, pain medication, and other drugs may be prescribed. Vision is usually restored after the foreign material is removed.
Injuries due to objects penetrating the eye are most common in dogs and cats. Lead pellets, bullets, splinters, and plant spines (such as cactus) can cause this type of injury. The eye should be examined for evidence of lens injury and other damage. Lens rupture is common with cat claw injuries. If the lens has been penetrated, it should be removed as soon as possible because perforation of the lens leads to rapid cataract formation. Bleeding, swelling, and glaucoma may develop also. Retinal detachments are common and often cause at least partial loss of vision.
Therapy aims to control swelling and maintain normal levels of pressure within the eye. A variety of drugs, including antibiotics and corticosteroids, may be used.
Corneal ulcers may develop when the eye is not lubricated enough (tear production is inadequate) or be caused by trauma (scratches or other injuries). Ulcers can become complicated and serious if infections occur. If you notice any increase in tearing, squinting, discoloration of the cornea, bulging of the cornea, or other abnormalities, a visit to the veterinarian is warranted. Dogs, cats, and horses are more likely to develop these problems, but they can be seen in other small animals as well. Some conditions require immediate surgery to save the eye. Potential complications include scarring or pigmentation of the cornea, and cataract formation.
Corneal lacerations or tears are most common in dogs and horses and rare in cats. Bites, self-inflicted trauma, and other accidents can partially or totally penetrate the cornea. Partial-thickness corneal lacerations are usually very painful. The wound may need to be closed with sutures. To provide protection and support, the sutured laceration may be covered. This may include stitching the eyelids closed temporarily. Antibiotics and other medications may be prescribed. Potential complications include corneal scarring, cataracts, glaucoma, and other serious eye disease.
Glaucoma is characterized by increased pressure in the eye and can lead to loss of vision. Signs of early to moderate glaucoma are subtle and may not be noticed. High intraocular pressure that develops suddenly may be noticed due to a dilated, fixed, or sluggish pupil, corneal edema (cloudiness), or a firm globe. Eye pain due to glaucoma may be noticed as a behavioral change rather than squinting (eyelid spasms). Some dog breeds have a greater risk for glaucoma, but which breeds varies from study to study. Consult with your veterinarian to decide if regular monitoring of eye pressure is right for your dog. Glaucoma is diagnosed by measuring the pressure in the animal’s eyes, which can be performed during routine annual exams. The procedure is called tonometry. The goals of therapy are to lower pressure rapidly and to preserve as much vision as possible. Medication is usually tried first, but if the glaucoma does not improve, surgery may be needed. Referral to a veterinary ophthalmologist (eye specialist) may be required.
Dislocation of the Lens
The lens of the eye can become dislocated and push forward. Lens dislocation usually affects middle-aged dogs of the terrier breeds. It is most common in Smooth and Wire Fox Terriers and Jack Russell Terriers. The eye may bulge from excess fluid and high intraocular pressure and appear red. Spasm of the eyelid and tearing may be evident. Treatment consists of lowering the pressure within the eye to normal levels and removal of the lens. Complications of lens removal include glaucoma and retinal detachment.
Acute Vision Loss
Acute loss of vision may occur with many eye disorders, brain or nerve diseases, or generalized illnesses. Blindness may be sudden. Usually, vision is lost in both eyes at the same time, but loss of vision in one eye can occur. For acute vision loss, large amounts of the retina must be involved. The optic nerve may be damaged. Evaluation of vision requires a thorough examination. However, because visual field evaluation cannot be performed in animals, subjective tests of vision are necessary. The veterinarian may perform tests of your pet’s response to flashing lights, moving objects, and other images. Referral to a veterinary ophthalmologist may be required.
Inflammation of the Optic Nerve
There are 2 main types of inflammation that affect the optic nerve. One, papillitis, is an inflamed optic nerve head that can be seen with an ophthalmoscope. In the other, retrobulbar optic neuritis, the animal’s pupils are dilated, and blindness is common. The inflammation is usually due to an undiagnosed widespread disease. Examination, blood tests, and other diagnostic procedures are done to confirm optic neuritis and to determine the cause, and treatment will be directed to resolving that. During the course of treatment, your veterinarian will watch for the pupils to return to normal size and respond to light. It may take several days for vision to be restored. Unfortunately, in some cases, optic neuritis can cause permanent blindness.
Degeneration or Detachment of the Retina
In sudden acquired retinal degeneration, vision is lost over several days. The pupils are generally much larger than normal and do not respond well to light. Middle-aged dogs are affected most often. Dogs with liver disease and certain hormone disorders may be more susceptible. There is no effective treatment.
Retinal detachment can cause vision loss in one or both eyes. Once retinal detachment is detected, immediate treatment can help restore vision. Some breeds, such as the Shih Tzu, are more prone to retinal detachment. Collie eye anomaly may also be related, but this form of retinal detachment is usually treatable. Trauma can cause retinal detachment. Certain diseases, including high blood pressure in cats and dogs, also contribute. Some retinal detachments involve holes and tears in the retina. Referral to a veterinary ophthalmologist may be required.
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