Q: My cat’s eyes are excreting a mucus like-fluid. My veterinarian said it could be an infection or allergies and gave me a very small tube of ointment to apply to her eyes, but I wonder what the cause of this is discharge? Can you provide any insight into this?
A: Thanks for getting in touch, and I very much understand your concern. Ocular (eye-related) discharge is a common problem in cats, and causes vary from relatively benign conditions to more serious ones that require prompt intervention. Perhaps a brief discussion of the more common causes of ocular discharge in cats would be helpful to you.
Feline ocular discharge can be broken down into two general categories:
- clear and runny (thin and not viscous)
- greenish/yellowish and thick (viscous)
Clear ocular discharge is most commonly seen in conditions that do not involve large amounts of dead white blood cells. Fluid with large numbers of these are generally referred to as purulent, characterized by the development of greenish or yellowish pus or discharge.
These include allergies to airborne allergens, environmental irritants, early trauma without bacterial infection, foreign bodies or ulcers in the cornea or conjunctiva (pinkish tissue that surrounds the eye), early/uncomplicated viral upper respiratory infections (i.e., herpesvirus, calicivirus), abnormal eyelids/lashes causing corneal trauma, and, in some cases, blockage or abnormal development of the nasolacrimal duct, a structure that normally drains tears from the eye to the nasal cavity.
In the latter case, the “discharge” is really just tears that cannot flow normally through the nasolacrimal duct (the tear duct) and spill out of the eye.
Greenish/yellowish, thick ocular discharge is caused by the accumulation of large numbers of white blood cells that respond to foreign microscopic invaders, such as bacteria and viruses, and to the presence of foreign objects such as plant material in the eye.
Generally speaking, whitish/yellowish discharge is of greater concern, and it is not uncommon for discharge to change from clear to greenish/whitish and thick as a disease process progresses (i.e., when a viral infection is complicated by secondary bacterial infection).
With respect to what to do if you notice ocular discharge in your cat, if everything else (appetite, activity level, temperature) is normal, it is OK to monitor your cat for a few days.
Things that should prompt seeking veterinary consultation include:
- an increase in the amount of discharge
- a change from clear to whitish/greenish discharge
- signs of discomfort including pawing at the eye
- squinting
- excessive blinking
Signs of systemic illness also warrant a call to your veterinarian. These signs include lethargy, loss of appetite, difficulty breathing, nasal discharge, swelling of the eyelids or the conjunctiva, and cloudiness of the eye.
The treatment of feline ocular discharge will depend upon its cause and the severity of signs and may include just keeping the eye clean by regular cleaning with a cotton ball moistened with saline solution, antibiotic or antiviral drops or ointment, system antibiotics, flushing of the eye to remove foreign material, antihistamines, and/or steroids to address inhalant allergies (like hay fever in people).
In less common cases, surgical intervention may be required to repair damage to the cornea of the eye, congenital defects of the eyelids and/or eyelashes, or blocked nasolacrimal ducts.
It is important that you work closely with your veterinarian and, in some cases, your veterinarian may refer you to a board-certified veterinary ophthalmologist to provide the best care for your cat.
If there is ever any doubt about whether a cat’s ocular discharge warrants veterinary examination, it is always best to err on the side of caution and contact your veterinarian.
I hope that this is helpful to you, and please send us an update about your cat when you can.
