Granulomatous anterior uveitis associated with bimatoprost

Purpose: To describe a previously unreported case of anterior granulomatous uveitis in a patient using bimatoprost. Methods: A 72-year-old woman with a long-standing history of anisometropic amblyopia and pseudoexfoliative glaucoma in the right eye started therapy with bimatoprost 0.03% once a day in the right eye. She had no previous history of ocular inflammation or ocular surgery. Her medical history was negative for systemic diseases associated with ocular inflammation. Results: After one week, the patient developed severe conjunctival injection, cells and flare, and numerous ‘mutton fat’ keratic precipitates in the right eye. Examination of the left eye revealed no evidence of inflammation. Bimatoprost was discontinued; no topical steroid therapy was started. Systemic investigations were normal. The inflammation resolved over two weeks, solely with the discontinuation of bimatoprost. Conclusions: Bimatoprost is a synthetic prostamide, chemically related to prostamide F. Prostamides are naturally occurring substances, biosynthesized from anandamide in a pathway that includes COX2. Even though anandamide has proven suggestive potential pro-inflammatory effects, the mechanism of induction of inflammation by bimatoprost remains uncertain and speculative. In our report, the onset of acute uveitis in a patient using bimatoprost, after a long-term and well-tolerated treatment with a prostaglandin analog, suggests a distinct potential pro-inflammatory action of prostamides. This can indirectly support the concept that the target receptor of bimatoprost is different, and that the mechanism of action of prostamides is pharmacologically unique.