• Understanding Antibiotic Resistance and Eye Infections

    Written By:
    Reviewed By: Ronald C Gentile MD
    Sep. 21, 2014

    Eye infections can turn serious, but is it always wise to take antibiotics?

    The problem of bacteria becoming resistant to antibiotics has long been a public health concern, but has grown into a serious issue in eye care because bacterial infections that do not respond to drugs can result in blindness.

    Any incisions or punctures to the eye can lead to infection. That means common eye procedures such as LASIK and cataract surgery inherently carry an extremely small risk of infection. In addition, injectable drugs, such as those commonly used to treat age-related macular degeneration and diabetic retinopathy, also carry a very small chance of infection.

    With approximately 3 million people undergoing cataract surgery annually and more than a million age-related macular degeneration injections being performed each year, the need to understand the issue of antibiotic resistance and eye infections has never been greater.

    How bacteria become resistant to antibiotics

    It used to be common practice for physicians to prescribe antibiotics for many types of infections, from the common cold to pink eye (also known as conjunctivitis). Physicians sometimes give antibiotics before surgery to prevent infection from occurring in the first place. Similarly, doctors have also used antibiotics following injections for treating age-related macular degeneration. All these practices, in addition to many other factors, are thought to have contributed to the increase in antibiotic-resistant bacteria. The more organisms become exposed to antibiotics, the more of a chance that a few will mutate in such a way that they can survive the drug’s attack mechanism.

    Drug companies continuously create new types of antibiotics to help fight infections, knowing that bacteria may eventually become resistant. However, these quickly-evolving organisms are finding ways around these drugs at an alarming rate, outstripping the pace of drug development.

    More bacteria are becoming resistant

    While the chances of eye infections for most individuals remains low, studies show that fighting these infections with available drugs is becoming harder and harder. Overall, bacteria have become increasingly resistant to many types of antibiotics. A 2014 study from the journal Ophthalmology that looked at drug resistance over a 25-year period found that more than half of all bacteria causing endophthalmitis, one of the most severe eye infections, are now resistant to the commonly-prescribed antibiotic cefazolin. Among the two most common Staphylococcus species encountered, bacterial resistance to the drug methicillin proved greater than 50 percent.

    With that in mind, healthcare providers have steered away from using antibiotics so freely in the last few decades. Physicians no longer provide antibiotics at the first sign of conjunctivitis because that is understood to contribute to resistance. (Also, conjunctivitis can be caused by allergies and viruses, neither of which can be cured by antibiotics.) Rather than apply antibiotic drops before drug injections to treat age-related macular degeneration or diabetic retinopathy, it is recommended to use iodine instead as a topical antiseptic, which has been shown to effectively cut the chance of infection.

    Get your doctor's advice about antibiotics for you

    Even so, there are times when drugs are needed to control infection, as in the case of a corneal ulcer or post-operative endophthalmitis. For some, the benefit of using antibiotics may outweigh the risk to help avoid losing vision.

    If you are undergoing eye surgery or getting treated with eye injections, talk to your ophthalmologist about what is appropriate for you and your situation. Each patient is different and has different risk factors, based on age, overall health condition and other considerations.