What is glaucoma?
The optic nerve is located at the back of the eye and contains all the nerve fibres responsible for your eyesight. Glaucoma is an eye disease that happens when these sensitive nerve fibres are affected by a rise or imbalance in the eye’s pressure, resulting in damage to the optic nerve and vision loss.
You can discover more about the several different glaucoma types here.
Risk factors for glaucoma
Lifestyle choices were never previously considered a risk factor for glaucoma, but recent studies1 have shown that lifestyle factors can influence eye pressure. Although high eye pressure does not necessarily cause glaucoma, it is a prominent risk factor.
Genetic factors are also thought to play a key role in all major forms of glaucoma. People at a higher risk include:
People of Afro-Caribbean descent above the age of 40
People across all ethnicities over the age of 60
People with a family history of the disease
In fact, primary open-angle glaucoma is considered largely hereditary.
What is your genetic risk?
Studies2 have shown that if members of your immediate family (a parent or a sibling) have glaucoma, your risk of developing early-onset glaucoma increases by almost ten times. The risk increases if your identical twin has glaucoma. The Finnish Twin Cohort Study (FTCS)3 first published in 1987 confirms that genetic factors play a role in glaucoma.
Troublesome genes and types of glaucoma they can cause
Congenital glaucoma is a condition that children are born with. The onset of congenital glaucoma happens before the age of three and is caused by mutations in two genes (CYP1B1 or LTBP2). These genes are inherited as an autosomal recessive trait, where both parents are carriers of the mutation but do not have glaucoma themselves. Their children can inherit both copies of the mutation, one from each parent, leading to the development of glaucoma.
Developmental glaucoma is another type of childhood glaucoma that appears between 10 to 20 years of age. It is associated with mutations in genes involved in the development of the eye — particularly in the front part of the eye and in structures draining the eye fluid. These developmental issues are usually inherited from one of the parents carrying a dominant gene, and may be associated with other developmental anomalies. For example, someone with developmental glaucoma may also have abnormal teeth or hearing loss.
People diagnosed with glaucoma before the age of 35 may have a form of glaucoma associated with a mutation in a myocilin gene. Mutations in this gene are also inherited as autosomal dominant traits, meaning that there’s a chance that parents with this form of glaucoma could pass it on to half of their children.
However, any form of glaucoma can have multiple gene variants that can place you in the risk group. It’s also important to note that even if someone in your immediate family has glaucoma, it doesn’t necessarily mean that you will develop it yourself.
Other risk factors
Aside from genetics, there are a number of other risk factors for glaucoma. Some of these include:
Age: you are six times more likely to develop glaucoma if you’re over 60
People with other general health conditions such as diabetes or blood pressure
Eye conditions, surgeries or injuries: injury to the eye may cause secondary open-angle glaucoma, immediately after the injury or some years later. A history of multiple eye surgeries for chronic eye conditions can also increase the risk because any eye surgery leads to inflammation. If the inflammation is particularly elevated, it damages the drainage structures, increasing the risk of glaucoma.
Regular users of asthmatic steroids: a study reported in the Journal of American Medical Association5 showed a 40% increase in the occurrence of open-angle glaucoma in adults who took 14 to 35 puffs of steroid inhaler to keep acute asthma in check.
Healthy lifestyle and exercise can reduce glaucoma risk
Even though glaucoma may be largely hereditary, most symptoms may not show up until later in life. Particularly if you have a family history of glaucoma or are above the age of 40, you should have an eye test at least every two years, or whenever your optician recommends it. Additionally, a recent study6 has shown that regular exercise can help to reduce the risk of glaucoma by improving blood flow in the body and your eyes.
For more information on glaucoma causes and risk factors, you can discover similar content in our dedicated glaucoma causes resource.
4. https://www.aao.org/topic-detail/congenital-glaucoma-europe and Taylor RH, Ainsworth JR, Evans AR, Levin AV. The epidemiology of pediatric glaucoma: the Toronto experience. J AAPOS. 1999 Oct;3(5):308–315. [PubMed] [Google Scholar]