Severe Acanthamoeba Keratitis After Overnight Orthokeratology

Abstract

To document a clinical case of Acanthamoeba keratitis associated with orthokeratology overnight lens wear that resulted in severe, permanent vision loss. Case report. At the age of 11 years, a boy received a spectacle correction for the following refractive error: -3.25 -0.50 x090 in the right eye and -3.50 -0.25 x 040 in the left eye. Alternative wear of daily-wear, disposable, soft contact lenses and rigid gas-permeable lenses was used for athletic activities to the age of 16 years. Between the ages of 16 and 19 years, the patient wore Boston Equalens 2c27 (type Percision Corneal Molding - 51) lenses with a base curve of 9.25, power of +2.50 diopters (D), and diameter of 10.6 mm in the right eye and a base curve of 9.15, power of +3.00 D, and diameter of 10.6 mm in the left eye for overnight orthokeratology wear. A corneal ulcer in the left eye was noted on November 13, 2004 (age of 19 years) and confirmed as Acanthamoeba infection by confocal microscopy on February 15, 2005, when triple topical therapy (Brolene, polyhexamethylbiguanide, and chlorhexidene) was initiated. Vision deteriorated to light perception with accurate projection by cessation of therapy on March 28, 2006. Additional complications included secondary angle-closure glaucoma, treated with an Ahmed tube shunt on April 12, 2005, and a mature cataract. The important message conveyed by this case was the finding that for several years, unknown to his eye care physicians, the patient cleaned his lenses with the Boston Cleaning System, as instructed, but followed this step with a routine rinse with tap water and storage in tap water in his lens case, which was not replaced or cleaned. The tragic loss of vision in this case probably could have been prevented by focused attention to lens hygiene by the patient, parents, and practitioner. Such heightened scrutiny is critically important in orthokeratology rigid lens wear, especially in children, independent of the lens polymer or fitting algorithm used.