Eye health could help diagnose people with ME
- Type of funding: Fight for Sight / Thomas Pocklington Trust Small Grant Award
- Grant Holder: Dr Claire Hutchinson
- Institute: University of Leicester
- Region: East Midlands
- Start date: June 2015
- End Date: May 2016
- Priority: Emerging threats
- Eye Category: Other
People with myalgic encephalomyelitis (ME) consistently report having trouble focussing on images, eye strain, vision-related headaches, slow eye movements and tracking moving objects, in addition to hypersensitivity to light and dry eye. So it’s possible that one or more of these symptoms experienced together with fatigue could be a defining feature of the condition. If so, it would make it easier for doctors to diagnose it, especially as none of the other symptoms people may experience are specific to ME.
In this project, the research team is testing 50 participants who have been diagnosed with ME to get an objective picture of eye problems that may be linked to the condition. They’ll be looking for information such as
- how often and how severely dry eye happens,
- how the participants’ pupils respond to light,
- how well they can focus on objects at different distances,
- clarity and depth of vision and
- the ability to perceive colour.
The team will also scan images of the participants’ eyes to find out whether the shape of the eye is affected and examine the retina at the back of the eye (which contains the ‘photoreceptor’ cells that detect light). This information will be compared to results from a control group of 50 participants without ME.
ME is also sometimes known as ‘chronic fatigue syndrome’.
On standard tests of functional vision, a number of notable problems were evident. ME patients showed deficits on ocular motility (the ability to move the eyes effectively), particularly when they had to move their eyes in an upwards direction. They were also less able than the control group to bring objects into focus (accommodation). Their pupils did not respond to light in the same way as controls, being narrower in diameter. Patients were also less able to discriminate between different colour hues.
When the researchers measured the ability to distinguish contrast (the smallest detectable difference between light and dark), patients' contrast sensitivity was worse in that they needed more contrast difference between adjacent parts of an image to be able to tell that they were different. The findings suggest that contrast sensitivity deficits may represent a visual marker of ME.
The researchers also took high resolution pictures of the different parts of the retina and preliminary findings suggest that there is some thinning in the photoreceptor layers of the retina in our patient group. These findings may represent useful biomarkers for ME and, as such, have potential diagnostic value.