Abstract:
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic, debilitating disorder. With the exception of disabling fatigue, there are few definitive clinical features of the condition. As a consequence, patients often have difficulty gaining an appropriate diagnosis. As such, identifying distinct clinical feature of ME/CFS is an important issue. One under researched area of ME/CFS associated symptoms concerns problems related to vision.
People with ME/CFS consistently report a range of symptoms related to the quality of their vision including pain in the eyes, hypersensitivity to light, difficulty focusing on images, slow eye movements, and difficulty tracking object movement. However, there has been little attempt to verify patients’ self-reports using objective methods. The purpose of the experiments presented in this thesis was to determine the effects of ME/CFS on: (i) performance on a range of tests of visual sensitivity and (ii) the morphology of the retina.
Compared to controls, the ME/CFS group exhibited reduced accommodation, larger pupil diameters, reduced colour discrimination and poorer contrast sensitivity towards lower spatial frequencies. Thinning in the photoreceptor layers of the retina (the Outer Segment & the Outer Nuclear layer) was also apparent. These findings support the claims of people with ME/CFS that they experience problems related to their vision and its function. They also represent a potential marker of ME/CFS that may aid in its diagnosis.