Pseudomonas aeruginosa is a common bacterium found in soil and water. It is an opportunistic pathogen that can cause a severe and rapidly progressing eye infection if it enters the eye, particularly when the cornea is compromised. The resulting infection, a form of bacterial keratitis, is aggressive and can threaten vision.
P. aeruginosa secretes enzymes called proteases that cause liquefactive necrosis, a process that rapidly breaks down corneal tissue. The bacterium’s virulence makes these infections more difficult to treat compared to those caused by other common bacteria.
Causes and Major Risk Factors
The most significant risk factor for a Pseudomonas aeruginosa eye infection is wearing contact lenses, especially for extended periods or overnight. Soft and extended-wear lenses provide a surface that the bacteria can adhere to. Over time, lenses accumulate coatings of proteins and other substances from tears, which can promote bacterial attachment.
The presence of a contact lens can shield bacteria from the natural cleaning action of the eyelids and tears. Lenses can also cause microscopic scratches on the corneal surface during insertion, removal, or from trapped debris. These injuries create a direct entry point for the bacteria to invade the cornea.
Poor hygiene, such as failing to wash hands before handling lenses, is a frequent contributor. Using contaminated lens solutions, “topping off” old solution instead of replacing it, or rinsing lenses and their cases with tap water can introduce the bacterium. Contact lens cases can also become breeding grounds if not cleaned and replaced regularly.
Recognizing the Infection
An infection with Pseudomonas aeruginosa is marked by the sudden and rapid onset of symptoms. One of the most prominent signs is intense eye pain that develops quickly. The eye becomes very red, vision may become significantly blurred, and patients often experience extreme sensitivity to light (photophobia) and a persistent sensation that something is in the eye.
A heavy discharge from the eye is another indicator. This discharge is often thick and may have a yellowish or greenish color. In some cases, a visible white or opaque spot may appear on the cornea, which is a sign of a developing corneal ulcer—an open sore on the eye’s surface.
An ophthalmologist diagnoses the infection through a comprehensive eye examination. To confirm the specific type of bacteria, the doctor will take a small sample by gently scraping the cornea. This sample is then sent to a laboratory to be cultured, which allows for the identification of P. aeruginosa and helps guide treatment.
Medical Treatment and Outcomes
A Pseudomonas aeruginosa eye infection is a medical emergency that requires immediate medical intervention to prevent severe vision loss. Treatment must be started promptly to control the infection’s rapid progression. The standard of care involves intensive antibiotic therapy administered directly to the eye.
This consists of high-concentration, fortified antibiotic eye drops, which are specially prepared by a pharmacy to be much stronger than commercial drops. In the initial stages of treatment, these drops may need to be applied as frequently as every hour, around the clock. Antibiotic ointments might also be prescribed for use overnight.
The outcome of the infection is directly tied to how quickly it is treated. Without prompt intervention, the bacteria can cause a rapidly enlarging corneal ulcer. This can lead to permanent corneal scarring, which can distort or block vision. In severe cases, the infection can cause the cornea to perforate, potentially leading to the loss of the eye. Even with successful treatment, some corneal scarring and vision impairment can remain.
Prevention for At-Risk Individuals
Preventing a Pseudomonas aeruginosa infection centers on meticulous hygiene for contact lens wearers. The most effective preventative measure is proper handwashing with soap and water before touching contact lenses or the eyes. This removes bacteria that could otherwise be transferred to the lens and then to the eye.
Strict adherence to lens care protocols is also necessary. This includes using a “rub and rinse” method with a disinfecting solution designed for the type of lenses being worn. Never use tap water or saliva to rinse or store lenses, as these can harbor P. aeruginosa and other harmful organisms.
Proper maintenance of the contact lens case is just as important as lens care. The case should be rinsed with fresh disinfecting solution—not water—and left open to air dry completely after each use. It is recommended to replace the contact lens case at least every three months. Following the wearing schedule prescribed by an eye doctor is also important, including avoiding sleeping in lenses unless they are approved for overnight wear.