How does a cell’s ability to make energy affect glaucoma?

Glaucoma is the most common form of damage to the optic nerve (optic neuropathy). It’s the leading cause of irreversible sight loss worldwide.

High eye pressure is the main risk factor for glaucoma, but it can happen at any level of pressure, high or low, so this is not the whole story. Older age is the second most important risk factor. Higher eye pressure is not linked to older age, however, so age seems to be a factor of its own.

A good measure of ageing is how well our mitochondria work. Mitochondria are the little compartments inside cells that make a chemical that the body uses for energy. They are vital for cell life and death.

The optic nerve is actually a bundle of connections from retinal ganglion cells – they connect the eye to the brain. These are the cells that die off in glaucoma.

Retinal ganglion cells have a high demand for energy and have sections that contain extra mitochondria. So it is likely that if mitochondria work less well with age, the optic nerve will suffer from not having the energy it needs.

The facts that a family history of the most common type of glaucoma is more likely on the mother’s side and that some people with high eye pressure and efficient mitochondria are glaucoma-resistant also point to mitochondria being involved in glaucoma. Mitochondria are passed on from mother to child.

In this study the research team want to find out whether mitochondrial function can predict who will be most at risk of optic nerve damage in glaucoma. Results should tell us how strong a link there is between mitochondria and the way glaucoma develops. We could have a blood test that can tell us whose sight to monitor most closely. It may also lead to a new approach to treating glaucoma.