Due to the relative rarity of Acanthamoeba keratitis (AK) compared to other causes of keratitis (bacterial, viral, etc.), it is often misdiagnosed, especially in the early stages of the disease.[20] AK should be considered in all patients who use contact lenses, and following corneal abrasions or trauma. A thorough history should be obtained, especially relating to contact lens use and any recent changes contact in lens solution, exposure of the eyes to water or foreign objects, and symptoms that the patient is experiencing. The symptoms classically attributed to AK include decreased or blurred vision, sensitivity to light (photophobia), redness of the eye (conjunctival hyperemia), and pain out of proportion to physical exam findings.[15][6] Another clinical feature that can distinguish Acanthamoeba from bacterial causes of keratitis is a lack of discharge from the eye.[11][3]