DIPP Study

Improving the Diagnostic accuracy of referrals for Papilloedema (DIPP)

What is papilloedema?

Papilloedema is nerve swelling at the back of the eyes. It is caused by increased pressure in the brain and may be a sign of a brain tumour. Some patients may have no symptoms and some have visual symptoms or headaches.

As 50% of people with a brain tumour have no symptoms, optometrists (eye care professionals who are trained to spot abnormalities in your eyes) may be the first to notice a problem.

Man having an eye examination resting chin on machine as light is shone into one eye.

The challenge

It can be hard to tell if someone has nerve swelling or not because there are many normal variations in how healthy nerves look that can be mistaken for swelling. These normal variations in nerve appearance, for example, 'crowded' optic nerves in long-sighted people, are collectively called pseudopapilloedema.

Special types of imaging can help diagnose nerve swelling. In the past, imaging tests were only used in hospital eye departments, but now some optometrists have them.

The problem is that optometrists refer many people to hospital because the test results aren’t clear or they’re not sure how to interpret them.

In Bristol, these referrals have increased by 500-600% in four years. This means that people who really do have nerve swelling may wait longer for appointments because more people with suspected nerve swelling are being referred.

Also, some patients are told they “might have a brain tumour” when they don’t, which causes lots of unnecessary stress and anxiety.

The COVID-19 pandemic has added to the problem by making waiting times for appointments even longer.

What we will do

We will develop guidelines for optometrists and GPs (primary care) to help them refer the right patients to hospital for further tests and reduce delays in diagnosis and treatment. We will also produce information leaflets for patients and members of the public.

See Aims of the study.

Who is funding this work

This study is funded by the National Institute for Health and Care Research (NIHR) School for Primary Care Research. Reference Number: 581, awarded December 2021, and NIHR Programme Development Grants, Reference NIHR204231, awarded May 2022.


For further information, contact: dipp-study@bristol.ac.uk


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