Glaucoma in high myopia

Abstract

High myopia is associated with an increased prevalence of glaucomatous or glaucomatous-like optic neuropathy after adjusting for intraocular pressure and other glaucoma-related parameters. The reasons for the assumed increased susceptibility for glaucomatous optic nerve damage in highly myopic eyes may be morphological changes in the intrapapillary and parapapillary region of the optic nerve head. This includes an elongation and thinning of the lamina cribrosa with a de-arrangement of the lamina cribrosa architecture, a steepening of the trans-lamina cribrosa pressure gradient, an exposure of the peripheral posterior lamina cribrosa surface to the orbital cerebrospinal fluid space, an elongation and thinning of the peripapillary scleral flange as the biomechanical anchor of the lamina cribrosa, and potentially a backward pull of the optic nerve dura mater on the peripapillary scleral flange in adduction. The clinical diagnosis of glaucomatous changes in the highly myopic optic nerve head is difficult due to the marked changes in the optic nerve head appearance by myopia itself. Glaucomatous optic nerve damage may be detected late in the course of the disease, in particular since the intraocular pressure is often within the normal range. The therapy of glaucoma in highly myopic eyes is similar to the treatment of open-angle glaucoma in non-highly myopic eyes, with the exception of a potentially increased risk of expulsive hemorrhage after glaucoma drainage surgery.