Non-glaucomatous Optic Disc Cupping: A Brief Review

Abstract

Although optic disc cupping is mostly seen in glaucoma patients, it can occur in non-glaucomatous optic neuropathies (NGON). The characteristics of NGON are cupping toxic optic neuropathies, optic neuritis, compressive ischemia, and hereditary nature. The basic components of optic disc cupping are prelaminar and laminar. Prelaminar thinning, which seemed to be non-specific, occurs in all types of retinal ganglion cell axon loss; such as compressive, ischemic, and inflammatory events; glaucoma; and aging. This form of cupping is usually shallow, with less excavation of the optic disc. Laminar type of cupping which is a clinically profound type of cupping, may damage peripapillary scleral and lamina cribrosa. Sometimes experienced clinicians cannot clearly distinguish glaucomatous from non-glaucomatous cupping. The non-glaucomatous optic neuropathy has more neuroretinal rim pallor with less excavation of the disc than in glaucoma. It also involves central visual acuity and color vision in primary levels with visual field defects aligned vertically and respecting the midline. Evaluation of the patient’s medical records, disease presentation, ocular function, and examination are also crucial. Secondary examinations, including visual field examination and optical coherence tomography (OCT) or neuroimaging, facilitate the disease’s differentiation. This review presents the methods of examining a patient with an increased cup-to-disc ratio.