Vigamox is a prescription antibiotic eye drop used to treat bacterial conjunctivitis, commonly known as pink eye. It contains moxifloxacin at a 0.5% concentration and belongs to the fluoroquinolone class of antibiotics. The standard treatment involves placing one drop in the affected eye three times a day for seven days.
How Vigamox Treats Bacterial Pink Eye
Bacterial conjunctivitis causes redness, swelling, and a sticky discharge from the eye, often making eyelids crusty in the morning. Vigamox works by blocking two enzymes that bacteria need to copy and divide their DNA. Without these enzymes functioning, bacteria can’t reproduce or repair themselves, and the infection clears.
This mechanism gives moxifloxacin broad coverage against many of the bacteria responsible for eye infections, including common culprits like staph and strep species. Because it attacks bacteria through two separate pathways rather than just one, resistance develops less easily compared to older antibiotic eye drops.
What to Expect During Treatment
The typical course is one drop in the affected eye, three times daily, for about seven days. You don’t need to shake the bottle before use. When applying the drop, tilt your head back, pull your lower eyelid down gently to form a small pocket, and squeeze one drop into that space. Try not to touch the tip of the bottle to your eye or any other surface, since that can introduce bacteria into the solution.
Most people notice improvement within the first two to three days, but finishing the full course matters. Stopping early because symptoms improve can allow surviving bacteria to bounce back and potentially become harder to treat. If your symptoms haven’t improved after a few days, the infection may be viral rather than bacterial, since Vigamox has no effect on viruses.
Common Side Effects
The most frequently reported side effects are mild and localized to the eye. These include a brief stinging or burning sensation right after applying the drop, along with minor eye irritation, dryness, or blurred vision that typically resolves within minutes. Some people notice a slightly unusual taste in their mouth shortly after application. This happens because the drops can drain through the tear duct into the back of the throat.
You can minimize this by gently pressing the inner corner of your eye (near the nose) for one to two minutes after putting in the drop. This blocks the tear duct and keeps more of the medication on the eye’s surface where it’s needed.
Contact Lenses and Other Precautions
If you wear contact lenses, you should generally avoid wearing them while you have bacterial conjunctivitis. The infection can contaminate lenses and cases, and wearing contacts over an inflamed eye slows healing. If your doctor does allow lens wear during treatment, remove your contacts before applying the drop and wait at least 15 minutes before reinserting them.
Vigamox is preservative-free in the sense that it doesn’t contain benzalkonium chloride, a preservative found in many other eye drops that can irritate the eye over time. This makes it a reasonable option for people who are sensitive to that particular ingredient.
Use in Children
Vigamox is approved for use in children, including infants as young as one year old. Bacterial pink eye is especially common in young children because of frequent hand-to-eye contact in daycare and school settings. The dosing for children is the same as for adults: one drop, three times daily, for seven days.
Vigamox vs. Moxeza
Moxeza is another moxifloxacin eye drop at the same 0.5% concentration, but it’s formulated differently to stay on the eye’s surface longer. The practical difference is dosing frequency: Moxeza requires only two drops per day instead of three. If remembering a midday dose is difficult, especially for children at school, Moxeza may be more convenient. Both products offer similar effectiveness against bacterial conjunctivitis.
One important distinction is that Moxeza contains xanthan gum as an inactive ingredient, which helps the drop stay on the eye longer but makes it unsuitable for any use inside the eye.
Off-Label Use in Eye Surgery
Ophthalmologists commonly prescribe Vigamox before and after cataract surgery to help prevent infection. This is an off-label use, meaning the FDA has not specifically approved it for that purpose. The drops are applied to the surface of the eye in the days surrounding surgery as a preventive measure.
Some surgeons have also used moxifloxacin directly inside the eye during cataract procedures to prevent a serious post-surgical infection called endophthalmitis. The FDA has raised concerns about this practice. Neither Vigamox nor Moxeza is approved for injection into the eye, and the FDA has received reports of a condition called toxic anterior segment syndrome (TASS) following intraocular use of compounded or diluted moxifloxacin products. TASS causes inflammation in the front of the eye and can damage vision. The FDA specifically warns that Moxeza should never be injected into the eye because its xanthan gum ingredient has been linked to causing TASS.
For patients, the practical takeaway is straightforward: if your surgeon prescribes Vigamox drops before or after eye surgery, applying them to the surface of your eye as directed is standard practice. Questions about any intraocular use are worth discussing directly with your surgeon.