Blind spots appear when glaucoma damages the fibers of the optic nerve. If the entire nerve is destroyed, you can become completely blind in that eye. The optic nerve is made up of many nerve fibers that carry images to the brain. It's like an electric cable, with many wires bundled together.

When there is more damage to the optic nerve, more, larger blank spots begin to appear in your field of vision. Many people don't notice these blank spots until the optic nerve is very damaged and these spots become large. This unnoticed vision loss is why people with glaucoma or are at risk for glaucoma should have regular eye exams as their opthalmologist suggests.

Is it possible to guard yourself against glaucoma?

Though there are currently no known ways to prevent glaucoma, recent research has indicated that a low carb, high fat diet may actually help guard against glaucoma—at least in mice. The ketogenic diet appears to protect retinal ganglion cells and their axons from degeneration, according to a May 14 report in the Journal of Neuroscience.

Scientists have known for years that the meticulously portioned diet, which shifts the body's metabolism into a state mimicking starvation, can protect against neurodegeneration. The diet staves off seizures in some people with drug-resistant epilepsy and has benefited patients with brain trauma, Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis.

The new study supports an additional benefit: prolonged maintenance of a ketogenic state may prevent degeneration of the optic nerve head in people with glaucoma.

Researchers from Northeast Ohio Medical University tested this idea, first proposed by a separate group in 2012, on a strain of mice that were destined to develop glaucoma. The DBA/2J mice were fed a diet of nearly 90% fat for 2 months. After 8 weeks, the diet boosted mitochondria production, increased energy availability, induced a strong antioxidant response and slowed degeneration of retinal ganglion cells and their axons.

"The intervention was successful despite the animals being on the cusp of significant glaucoma progression," the investigators stated.

The findings shed light on the metabolic underpinnings of glaucoma, the authors say, and suggest the diet could potentially benefit people with the condition. More studies are needed to confirm the findings.