Last updated May 31, 2024
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Does your cat have a little eye goop? Or a full-blown infection with sneezing and crusty eye discharge? It’s important to know when eye drops are appropriate and the best eye drops to use. In this article, we’ll review five common types of eye drops used for eye infections in cats.
Eye Infections in Cats
Eye goop can appear for reasons such as conjunctivitis, feline herpes virus, or allergy. sophiecat / Shutterstock.com
Eye infections in cats can be either viral or bacterial growth that develops on the surface of the eye (keratitis) or in the conjunctival tissues around the eye and under the lids (conjunctivitis).
Infections can be primary or secondary. In a primary infection, a viral or bacterial organism enters the eye tissue and directly causes an infection. Two viruses and two bacteria, Mycoplasma and Chlamydia, and feline herpesvirus-1 (FHV-1) and feline calicivirus, commonly cause primary eye infections in cats.
In a secondary infection, there is some other primary cause responsible. This can include a range of eye conditions, such as a scratch or other trauma to the eye, foreign body, irritants and particulate debris like dirt or pollen, autoimmune disease, or eye/eyelid defects. This other primary cause affects the eye’s ability to repel infection. Many types of bacteria may contribute, including Staphylococcus, Escherichia coli, Pseudomonas, and Enterococcus.
How Eye Infections Are Diagnosed and Treated in Cats
When I see pets present for an eye infection, there are a few different things I look for.
Is it one eye or two? A sudden onset of one eye showing signs of infection as well as signs of pain like squinting, are more supportive of trauma or another underlying condition contributing to a secondary infection. If both eyes appear equally affected, a primary cause may be more likely.
What does the discharge look like?: Clear or watery discharge can be more supportive of a viral disease or allergy-related cause. Yellow, green, or white discharge is more concerning for bacterial infection.
Fluorescein stain: This test to check for an ulcer or scratch on the corneal surface of the eye involves applying a green dye to the eye surface, then rinsing it out. Any defect in the cornea, like a corneal ulcer, will take up the dye, which fluoresces under UV light. This is a common test performed at the vet’s office for eye infections, especially when a single eye is involved and the onset was very sudden.
Conjunctival cytology and culture: Your vet may perform cytology or cell sample collection to determine whether a bacterial infection is present. In cases where antibiotics are not effective but a bacterial infection is suspected, a culture may be performed to verify the infection and determine what antibiotic type may be most effective.
6 Best Eye Drops for Cats
Regardless of the type of eye drop used, most come in a small dropper bottle. Jarva Jar / Shutterstock.com
The following antibiotic eye drops are commonly prescribed as topical treatment for cats. You’ll see their ingredients, potential side effects, and additional info.
#1 Terramycin
- Key ingredients: oxytetracycline hydrochloride and polymyxin B sulfate
- Purpose: antibiotic eye ointment
- Possible side effects: a rare allergy or hypersensitivity may occur in any individual, but is considered rare. A very rare but serious anaphylactic reaction to polymyxin B has been reported in cats.
Terramycin is a brand name for the oxytetracycline and polymyxin B sulfate combination that is a common choice for cats. Oxytetracycline is very effective against suspected Mycoplasma and Chlamydia infections. Terramycin is only available as a topical antibiotic ointment.
#2 Erythromycin
- Key ingredients: erythromycin
- Purpose: antibiotic
- Possible side effects: may include stinging, burning, irritation, and redness of the eyes.
Erythromycin is usually effective against Mycoplasma and Chlamydia, as well as Streptococcus and Staphylococcus. It is typically available as a generic product under many different manufacturers. It is more commonly available as an ophthalmic ointment.
#3 Tobramycin
- Key ingredients: tobramycin
- Purpose: antibiotic
- Possible side effects: Burning and irritation on application as well as conjunctival swelling and redness. Cats are more sensitive to tobramycin’s drug class, the aminoglycosides, which can cause kidney and neurologic toxicity when used systemically.
Although toxic effects are unlikely with an eye medication form, close monitoring for systemic illness (changes in appetite and litter box use, lethargy, etc.) should be considered as a precaution.
Tobramycin has a large spectrum of activity and is often used as a first choice for secondary eye infections, especially ones caused by Escherichia coli, Klebsiella, Proteus, Pseudomonas, Salmonella, Enterobacter, Serratia, and Shigella.
#4 Ofloxacin
- Key ingredients: ofloxacin
- Purpose: antibiotic
- Possible side effects: blurred vision, tearing, eye pain, redness, and itching
Ofloxacin is considered a higher-line antibiotic that may be used in cases where a culture supports its use or if the desired result is not achieved with another antibiotic for a secondary infection. It has efficacy against susceptible strains of Staphylococcus, Pseudomonas, Streptococcus, Chlamydophila, and Haemophilus.
#5 NeoPolyDex
- Key ingredients: neomycin sulfate, polymyxin B, dexamethasone
- Purpose: antibiotic and steroid
- Possible side effects and precautions:
- Cats can rarely develop severe and life-threatening anaphylactic reactions to neomycin sulfate and polymyxin B requiring careful monitoring after first use. Signs can include itching, redness, and swelling of the conjunctiva and eyelid before progressing to an anaphylactic reaction.
- An eye drop with a steroid should never be used if an active wound or ulcer is present on the surface of the eye, as this will lead to delayed wound healing or worsening.
- While uncommon, topical corticosteroid ointment or eye drops can have systemic effects requiring caution in cats with diabetes or acromegaly, infectious diseases, kidney disease, heart failure, hypertension (high blood pressure), or stomach ulceration.
- Increased intraocular (inside the eye) pressure
Neomycin-Polymyxin-Dexamethasone contains two antibiotics and a steroid. It is a common first-line choice to use in cats if infection is suspected and an anti-inflammatory is needed, but there is no evidence of trauma or ulceration of the corneal surface (as topical steroid use can make such things worse).
#6 NeoPolyBac (Vetropolycin)
- Key ingredients: neomycin, polymyxin B, bacitracin
- Purpose: antibiotic
- Possible side effects:
- Irritation and swelling on application
- Individual cats can develop a severe and potentially life-threatening anaphylactic reaction to neomycin sulfate and/or polymyxin B. Though considered rare, close monitoring is important following a first dose.
NeoPolyBac has the same ingredients as Vetropolycin, which is labeled for use in animals. This is a common triple antibiotic ointment or eye drop approach, especially for secondary infections.
Neosporin’s ophthalmic preparations also contain neomycin and polymyxin B. But instead of bacitracin, gramicidin is the third ingredient. Although available over the counter, this medication can still present the rare side effect risk for cats.
How To Administer Eye Drops to Cats
Administer eye drops to your cat with them facing away from you and in as relaxed a position as possible to reduce stress for both of you. 135pixels / Shutterstock.com
Administering eye drops can sometimes be a bit of a daunting task. But I think one of the most common mistakes with trying to give cats medicine is to do it head on. If you get anything too close to a cat’s face their tendency is going to be to back up, or to take one of their furry mitts and whack your hand.
So whenever giving a medication (in the eyes, ears, or mouth) try doing it with your kitty facing away from you. One method is to have them sit in your lap. A strategy I use often is to kneel behind one of my cats.
To administer an eyedrop, tilt your kitty’s head up towards the ceiling. For the right eye, I use my left thumb to pull back the upper lid. With my right hand I use my middle finger to drop the lower lid, then my thumbs and forefinger to squeeze the bottle.
It takes a little practice, but when done quickly, your cat won’t see the bottle coming at them. This also keeps you out of the way of a swatting furry mitt.
I also think a distraction can help. I like to give my cat eye drops right after I put his food bowl down. Like many cats, he’s magnetized to his food bowl at mealtimes, which makes him reluctant to go anywhere else. A quick eyedrop and he’s back to his meal.
If your cat is already a bit difficult with medication, or if a food distraction isn’t helpful, you can wrap your kitty in a towel or small blanket, keeping just their head exposed.
It is very important when applying eye drops to not touch the corneal surface of the eye with the dropper bottle.
How Often Should I Give Eye Drops to My Cat?
When treating an eye infection with eye drops, it’s important to get 1-2 good drops in the affected eye(s) at least every 12 hours (each morning and evening). However, some infections may resolve faster with more frequent administration, as often as every 4 hours, if you’re able to.
How Long Do I Give Eye Drops to My Cat?
Many uncomplicated cases of bacterial conjunctivitis can resolve within 5-7 days. However, the full length of time needed may depend on the underlying cause. Cats with suppressed immune systems with viral flare ups of herpes or calicivirus may take longer for their secondary infections to clear up. If trauma occurred or a large ulcer is present, these will take time to heal.
If your vet is concerned about monitoring the healing process for your cat’s eye(s), make sure to follow your cat’s antibiotic medication instructions closely and keep any follow-up visits for rechecks. If an ulceration was present, your vet will repeat the fluorescein dye test to see if the ulcer has healed.
Drug Dosing Disclaimer: We are only able to provide doses for medications that are FDA approved for use in cats and only as the label guidelines dictate. For medications that are used off-label we can only provide guidelines and safety information for use. Safe and appropriate dosing for off-label medications can only be determined by a primary care veterinarian.
We encourage you to work with your veterinarian to determine if a particular medication is appropriate for your cat. Changing or adjusting a dose for your cat on your own without consulting with a veterinarian can carry risk. We do not encourage use of medications prescribed for human use in pets without first consulting with a primary care veterinarian.
Frequently Asked Questions
How can I treat my cat’s eye infection at home?
Many eye infections in cats are viral in nature and do not require antibiotic drops. Mild signs can be cared for with home remedies by keeping any eye discharge or residue at bay with a warm washcloth.
If signs of infection worsen after a couple of days of home care, or if any kind of trauma to the eye is suspected, you should have your cat examined by your vet.
Can I use human antibiotic eye drops on my cat?
There are antibiotic human eye drops that are the same type that are used in cats. However, none of them are labeled for use in cats, including Neosporin's ophthalmic preparations. Because of that and because there are non-infectious conditions that could be the cause of your cat's symptoms that may not require antibiotics, it is best to check with your vet before using any human medications you have at home for your cat.
Can Terramycin be bought over the counter?
Terramycin can be purchased without a prescription in most cases. The exception is in California, where purchase requires a prescription. Even though it can be purchased OTC, it should still be used judiciously and discussed with your vet prior to use. As the polymyxin B component may cause a very serious but rare reaction in some cats, careful monitoring after the first application is important.
What do vets prescribe for conjunctivitis in cats?
This depends on the suspected cause of conjunctivitis and its severity. Conjunctivitis may be viral (most common in cats), caused by an allergy or irritant, trauma, or a bacterial infection. Most cases of viral conjunctivitis like feline herpes virus infection resolve on their own and eye drops are rarely prescribed. If indicated, antibacterial eye drops may be prescribed based on a bacterial culture or the types of bacteria suspected to be involved.
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