Fluorometholone eye drops are a mild corticosteroid used to treat inflammation on the surface of the eye and in the front chamber behind the cornea. They’re typically prescribed for conditions affecting the conjunctiva (the clear membrane covering the white of the eye), the cornea, and the anterior segment of the eye. Because fluorometholone is less potent than stronger steroid eye drops, it’s often chosen when inflammation is moderate or when a gentler, lower-risk option is preferred.
Conditions It Treats
Fluorometholone is FDA-approved for steroid-responsive inflammatory conditions of the eye. In practical terms, that covers a broad range of situations: allergic conjunctivitis that hasn’t responded to antihistamine drops, inflammation following minor eye procedures, irritation from contact lens wear, and certain types of keratitis (inflammation of the cornea). It’s also used after some eye surgeries to manage swelling and redness during healing.
The key phrase in the approval is “steroid-responsive,” which means the inflammation needs to be the kind that calms down with a corticosteroid. Not all eye inflammation fits that description. Infections caused by bacteria, viruses, or fungi generally require different treatment, and using a steroid on an active infection can make things significantly worse.
How It Reduces Inflammation
Fluorometholone works by blocking the production of chemicals your body makes during an inflammatory response. Specifically, it triggers your cells to produce proteins that shut down the release of arachidonic acid, a fatty acid that serves as the raw material for prostaglandins and leukotrienes. These are the molecules responsible for the swelling, redness, pain, and heat you feel when tissue is inflamed.
By cutting off that chain reaction near the beginning, fluorometholone reduces swelling, limits the migration of immune cells into the affected area, and slows the growth of new blood vessels that can cloud the eye’s surface. One tradeoff: because corticosteroids dampen the immune response, they also slow healing. That’s why your prescriber will typically taper the drops rather than stop them abruptly, and why the duration of treatment matters.
Why It’s Considered a Milder Steroid
Among ophthalmic steroids, fluorometholone sits on the gentler end of the spectrum. Prednisolone acetate 1% is the stronger, more commonly used option for serious inflammation like post-surgical flare-ups or aggressive uveitis. Fluorometholone 0.1% is less potent, which is both its limitation and its advantage.
In a clinical comparison of patients recovering from corneal transplant surgery, only 2% of those on fluorometholone needed to switch to a stronger steroid, while 8% of those on prednisolone had to switch to a weaker one because of pressure-related side effects. That tradeoff captures the drug’s profile well: it’s less likely to spike eye pressure, but it may not be strong enough for the most aggressive inflammation.
For post-cataract surgery inflammation specifically, fluorometholone may not be the best standalone choice. In one multicenter trial, over half of eyes treated with fluorometholone alone after cataract surgery developed cystoid macular edema (a type of retinal swelling), compared to under 6% in the group using a nonsteroidal anti-inflammatory drop. For major surgeries, stronger steroids or combination regimens are often preferred.
How You’ll Use It
The standard dose is one drop in the affected eye two to four times daily. During the first 24 to 48 hours, your prescriber may have you use it as often as every four hours if inflammation is significant. You’ll need to shake the bottle well before each use, since the active ingredient is a suspension that settles at the bottom.
As your symptoms improve, the frequency gets gradually reduced. This tapering is important. Stopping corticosteroid drops suddenly after extended use can cause a rebound flare of inflammation. For chronic conditions, the step-down is especially gradual, sometimes stretching over weeks.
Side Effects to Watch For
The most common side effect is a brief stinging or burning sensation right after you put the drop in. Some people also notice a temporary change in taste (the drops can drain through the tear duct into the back of the throat) or a feeling like something is in the eye. These are generally harmless and short-lived.
The more serious concern with any steroid eye drop is elevated pressure inside the eye. Fluorometholone causes this less frequently than stronger steroids, but it still happens. Sustained high eye pressure can damage the optic nerve, the same mechanism behind glaucoma. Prolonged use can also contribute to cataract formation, specifically a type called posterior subcapsular cataract that develops on the back surface of the lens.
Other effects that warrant attention include blurred vision, increased light sensitivity, eye pain or redness that worsens rather than improves, and any noticeable change in vision. If the drops are used for more than a couple of weeks, periodic pressure checks are standard practice.
When It Should Not Be Used
Fluorometholone is contraindicated in several specific situations:
- Herpes simplex keratitis: The most common viral infection of the cornea. Using a steroid can allow the virus to spread deeper into the eye.
- Fungal eye infections: Steroids suppress the local immune response, giving fungal organisms room to grow unchecked.
- Vaccinia and varicella infections: Viral conditions related to smallpox vaccination and chickenpox, respectively.
- Untreated bacterial infections: A steroid can mask the symptoms of a worsening infection, making it look like things are improving when they’re not.
- Mycobacterial eye infections: Rare but serious infections that require targeted antimicrobial treatment.
This is why fluorometholone is a prescription medication rather than an over-the-counter option. The conditions it treats and the conditions it worsens can look similar on the surface, so an accurate diagnosis before starting treatment is essential.
Available Formulations
Fluorometholone comes in two main concentrations. The standard version is a 0.1% suspension, sold under various brand and generic names. A stronger version, 0.25%, is available as FML Forte for cases that need a bit more anti-inflammatory power while still staying below the potency of prednisolone. There’s also fluorometholone acetate 0.1% (sold as Flarex), a slightly different chemical form that may penetrate the cornea more effectively.
All versions are ophthalmic suspensions, meaning the medication particles are suspended in liquid rather than dissolved. That’s why shaking the bottle is not optional. If you skip that step, the first few drops will be mostly liquid with little active drug, and the last drops will be overly concentrated.