title: A hypothesis to suggest that light is a risk factor in glaucoma and the mitochondrial optic neuropathies.
abstract: The authors propose that light entering the eye interacts with retinal ganglion cell (RGC) axon mitochondria to generate reactive oxygen intermediates (ROI) and that when these neurons are in an energetically low state, their capacity to remove these damaging molecules is exceeded and their survival is compromised. They suggest that in the initial stages of glaucoma, RGCs exist at a low energy level because of a reduced blood flow at the optic nerve head and that in the mitochondrial optic neuropathies (MONs), this results from a primary, genetic defect in aerobic metabolism. In these states RGCs function at a reduced energy level and incident light on the retina becomes a risk factor. Preliminary laboratory studies support this proposition. Firstly, the authors have shown that light is detrimental to isolated mitochondria in an intensity dependent manner. Secondly, light triggers apoptosis of cultured, transformed RGCs and this effect is exacerbated when the cells are nutritionally deprived. Detailed studies are under way to strengthen the proposed theory. On the basis of this proposal, the authors suggest that patients with optic neuropathies such as glaucoma or at risk of developing a MON may benefit from the use of spectral filters and reducing the intensity of light entering the eye.
authors.affiliation: Nuffield Laboratory of Ophthalmology, University of Oxford, Walton Street, Oxford OX2 6AW, UK. neville.osborne@eye.ox.ac.uk
authors.forename: N N
authors.initials: NN
authors.lastname: Osborne
authors.forename: G
authors.initials: G
authors.lastname: Lascaratos
authors.forename: A J
authors.initials: AJ
authors.lastname: Bron
authors.forename: G
authors.initials: G
authors.lastname: Chidlow
authors.forename: J P M
authors.initials: JP
authors.lastname: Wood
mesh_terms: D017209:Apoptosis / Q000528:radiation effects; D005901:Glaucoma / Q000378:metabolism*; D006801:Humans; D008027:Light / Q000009:adverse effects*; D008928:Mitochondria / Q000378:metabolism / Q000528:radiation effects*; D009898:Optic Disk / Q000098:blood supply; D009901:Optic Nerve Diseases / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012039:Regional Blood Flow; D012165:Retinal Ganglion Cells / Q000378:metabolism / Q000528:radiation effects*; D012307:Risk Factors
chemical_list: D017382:Reactive Oxygen Species