Research article Open access Discontinuation of the herbal preparation Hypericum perforatum, also known as St John's wort, associated with improved intraocular pressure control in a patient on topical beta-blockers for primary open-angle glaucoma Magdalena Edington, Thomas Siempis, Donald Montgomery · Oman Journal of Ophthalmology · 2018 · 10.4103/ojo.ojo_165_2017