This is a water-borne bacteria that commonly sticks to contact lenses and can cause a corneal ulcer. Pseudomonas is the same bacteria that causes “swimmer’s ear” and it tends to proliferate in watery environments (such as contact lens solution and within contacts themselves). If this bacteria colonizes the cornea, it can cause a bad corneal ulcer. Pseudomonas infection can be challenging to treat as it tends to be resistant to many of the older antibiotics. For this reason, any infection related to contact lens use needs to be evaluated by an eye doctor and treated with aggressive antibiotics.