Contact Lens-Induced Peripheral Ulcer (CLPU)
Contact Lens-Induced Peripheral Ulcer (CLPU) is a unilateral response of the cornea occurring as a result of colonization of contact lens surfaces by pathogenic Gram-positive bacteria, primarily Staphylococcus aureus and S. epidermidis. (Your dirty contacts actually have bacteria growing on them) Although seen with daily wear lens use, CLPU is more commonly observed with EW usage. (People who chose to sleep in there contacts have more problems more frequently) Toxins released by the bacteria warranty an on sight response of your body’s protective white blood cells, which gives rise to a whitish/gray focal anterior stromal infiltrate in the periphery or mid-periphery of the cornea. (The bacteria growing on your dirty contact produces toxic waste that is damaging to your eye) The round infiltrate can range in size from 0.1mm to 2.0mm,22 and during the acute presentation will show a full-thickness loss of epithelium. (The top protective layer of your eye is damaged and open for an infection to set in) Symptoms may be absent, or may be significant with moderate foreign-body sensation, redness and tearing.
Symptoms rapidly decrease, and the epithelium resurfaces over the lesion, leaving a well-demarcated grayish scar. This scar often assumes a “bulls-eye” appearance and gradually fades after six months. A common clinical observation in contact lens practice is the presence of a newly discovered round scar in the peripheral cornea of an established patient wearing EW hydrogel lenses. This shows that the inflammatory events associated with CLPU are often so mild as to escape patients’ attention. Approximately 50% of CLPUs present as scars in the absence of symptoms.9
Patients who experience repeat episodes of CLPU are likely to have high levels of S. aureus and/or S. epidermidis on their lids and lashes. Overnight lens wear is best avoided in these patients.23,24 CLPUs are seen in patients wearing EW hydrogel lenses and CW silicone hydrogels. The elimination of hypoxia does not eliminate the risks of this complication. (Wearing the overnight approved, “breathable” contact lenses does not prevent this serious event from happening). This is suggestive that it may be strongly related to the duration (not the material) of the contact lens being on the eye, in particular, how long a dirty contact remains in contact with the eye.
To summarize: Although serious and potentially vision threatening, this is not an active infection in your eye. CLPU and the associated symptoms result from an attack on the cornea and the body’s immune response to that insult. Please be advised that a more serious type of active infection can occur via a similar pathway.
My treatment program requires an immediate, yet temporary discontinuation of contact lens wear. A prophylactic and supportive treatment with an antibiotic/steroidal eye drop to prevent infection, will also help to heal the cornea and make the eye more comfortable. The course of treatment is usually from 3-5 days, with an average of a week without contact lens use. Once the cornea has healed, (re-established its top protective layer), contact lens use can be restored. Hopefully, it will be in a daily disposable contact lens, which will provide the lowest risk of reoccurrence and the highest risk for maintaining healthy eyes.