Glaucoma risk factors and the case for targeting screening programmes

Glaucoma is symptomless in its early stages and, because of this, it is estimated that at any time 50% of cases are undetected. Eye health professionals and patients need an understanding of risk factors in order to detect undiagnosed cases, to conduct early screening and treat the condition before it advances.

Knowing the risk factors for any condition also allows a healthcare professional to educate patients as early as possible. If a patient knows they are more at risk they are more likely to have sight tests and if an eye care professional knows about these risks they can encourage the right groups to have regular tests.

Risk factors for glaucoma

There are two major types of glaucoma, angle closure glaucoma and primary open-angle glaucoma. Both kinds have common risk factors associated with them, but there are risk factors are unique to each type.

Risk factors for angle-closure glaucoma:

  • Aged 40 or older
  • Family history of glaucoma
  • Farsightedness
  • History of eye injury or eye surgery
  • East Asian or Inuit ethnicity

Risk factors for primary open-angle glaucoma:

  • Elevated eye pressure
  • Family history of glaucoma
  • Aged 60 or older, for general population
  • Aged 40 or older for those of African descent
  • Thin corneas (less than 0.5mm)
  • ‘Increased cupping’ in the optic nerve – i.e., the space at the centre of the optic nerve is larger than normal

Other risk factors for these major types of glaucoma (as well as normal tension glaucoma) include cardiovascular disease, low eye pressure, diabetes and low blood pressure.

At this stage, elevated eye pressure (or IOP, intraocular pressure) remains the only modifiable risk factor for glaucoma. It was previously thought to be the only reason glaucoma develops, but this has since been recognised to be untrue, other factors play a role. IOP can be controlled with eye drops or pills, which the patient must adhere to in order to prevent glaucoma progressing further.

How understanding risk factors improves patient care

Once a person reaches the age of 40 they should have an eye test annually in order to pick up early signs of glaucoma or other eye diseases. Early detection is very important for conditions like glaucoma. Treatments have now become very effective, so there is no need for sight to be lost in many cases.

Family history plays a large role in glaucoma risk, so it is important for eye health professionals to know as much as possible about a patient’s background. This information allows them to single out groups most at risk of glaucoma and invite them for glaucoma screening more regularly than others.

Along the same lines, if a patient has regular sight tests their eye doctor is more likely to know about any past or current eye conditions. Having this information, about farsightedness or previous eye injury, helps an optometrist or ophthalmologist assess the risk of glaucoma more effectively.

What is obvious here is that good communication with patients will help detect glaucoma earlier and optimise patient care. A patient who is comfortable having a sight test is more likely to continue seeing you in older age when complications are more likely to occur.

Targeted screening

In a survey by the RNIB, it is reported that fear of sight loss is stronger than the fear of other disabilities. 94% of survey respondents feared blindness more than deafness, and 95% feared it over having to use a wheelchair. Despite this 47% of respondents over 60 years of age said they did not have an annual sight test.

Why is this? The study reported that 60% did not go because they didn’t perceive any problem with their eyes. Glaucoma is symptomless in the early stages – so many of these people may have had the condition but assumed they were healthy, due to lack of symptoms. When symptoms do occur the condition is much more advanced and sight is harder to save.

Sight loss from glaucoma is unnecessary in most cases, and given the negative impact it can have on a person.

Ideally, everyone who is over the age of 60 should have a glaucoma screening test at least once a year. As you can see from the above figures, this can be hard to achieve, so the next best step is to target those most at risk.

Knowing the common risk factors for glaucoma helps us single out groups in a clearer, more organised way. This information then helps eye health professionals to select a group of people as part of a targeted screening programme. Taking an approach like this helps increase the probability of finding those with early glaucoma, without the huge costs associated with screening the general population.

visual field screening, visual field analysis, ZATA test

How can we improve glaucoma screening rates?

Currently, many glaucoma cases are detected on an opportunistic basis, rather than as a result of a targeted screening programme. Screening the general population requires massive resources that most healthcare systems simply do not have. Cases of glaucoma are increasing, however – especially with our ageing western population – so action should be taken.

Accurate and portable equipment, like our Henson 9000, can be used to quickly screen those most at risk, in a clinic or within the community. Developing patient relationships and awareness programmes, as well as investing in efficient equipment, creates the ideal scenario for improving early screening rates for glaucoma.

Alongside this, knowledge of the risk factors for glaucoma allows professionals to cost-effectively screen the right people, and diagnose as many early cases of glaucoma as possible within a community.

Read more about targeted screening programmes for glaucoma in our free whitepaper, or learn more about the Henson 9000 perimeter.