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CFS - Eye Problems
People with ME/CFS often complain of visual propblems, but a simple sight test may not show anything wrong. Opticians and doctors who are consulted may not be able to explain the symptoms.
Date: 3/6/2005 6:31:10 PM ( 19 y ) ... viewed 7643 times Eye Problems in ME/CFS
By Dr Anne Macintyre
Reprinted from Perspectives September 1997
People with ME/CFS often complain of visual propblems, but a simple sight test may not show anything wrong. Opticians and doctors who are consulted may not be able to explain the symptoms.
What sort of problems are experienced?
Short term blurring of vision
Difficulty reading eg. inability to focus clearly or jumping of the lines of print
Increased sensitivity to light (photophobia)
Intolerance of some visual patterns and moving objects eg. TV or computer screen
Floaters (bits which appear to float across the sight)
Discomfort, pain, redness or watering of the eyes.
The causes of the problems may be in the eyes themselves, or in the function of the eye muscles or from malfunctions in the brain. The abnormal easy fatigability of muscles and brain that is typical of ME/CFS may also apply to using the eyes and interpreting visual stimuli.
When you change focus from a distant object to a near one of from near to far, two things happen:
As in a camera, the lens in each eye must change focus in order for a clear image to fall on the retina. This work is done by the ciliary muscle which is attached to the lens of the eye behind the iris. With increasing age the lens becomes harder and this reduces the efficiency of the ciliary muscle which is why people over 40 often need reading glasses. people with ME.CFS may need earlier and stronger reading glasses than expected becauses their ciliary muslces fatigue easily.
The other effect of focusing on a near object is that the eyes have to look inwards, converging towards the nose. This is achieved by the work of the muslces attached to each eye on their nasal side. Each eye has 6 external muscles which ove the eyes in all directions. Normally, focusing and convergence are finely balanced, the co-ordination for these two actions taking place in the brain.
If the converging eye muscles are weak or tired, there is difficulty maintaining a clear single image on close vision - patients may find they shut one eye to read, or that the eyes ache after a time. Sometimes a prism in the glasses may help weak convergence, but most opticians prefer to teach eye exercises to strengthen the converging muscles (often difficult with ME/CFS because the muscles tire easily).
If you are fatigued, you may notice transient blurring on looking in the distance after close work. This can be caused by a delay in both the change of fucus on the eyes' lenses and the eye muscles which direct the eyes straight again - the eyes may overcompensate to give divergence, again leading to blurred or double vision.
An adult who gets ME/CFS may have had excellent control for year of both eyes, to give fused single image vision. This is achieved by miraculous co-ordination of the fine movements of all the eye muscles - a process we never need to think about. IF these eye muslces either fatigue, or do not work in co-ordination, we may see two images. The fault may be (rarely) in damage to one of the nuclei (nerve centres) in the brainstem which send impulses down nerves to the eye muslces: this happens in neurological diseases such as Multiple Sclerosis. In ME/CFS, double vision is more likely to be caused by eye muscle fatigue. If persistent double vision develops, a thorough neurological assessment should be carried out to look for other conditions.
Sometimes in ME/CFS, looking at moving objects causes discomfort, nausea and blurring - this applies especially to passengers in a moving car of train. The rapid flicking of the eyes in a person looking at moving objects is called 'saccadic eye movements'.
Such movements can become disturbed, if there is any problem with the reflexes in the brain that control them. This can happen in ME/CFS and other neurological conditions. Following a line of print when reading can also be a problem.
Sensitivity to light and visual patterns
These problems may not always come from the eyes themselves, but from some altered perception by the part of the brain that registers what we see. This is the visual cortex, which is part of the surface area of the occipital lobes at the back of the brain. Light and images may be perceived as too bright or too confused by people with ME/CFS eg. moving shiny lines on the steps of escalators or moving images on TV screens are a problem for many people.
Another reason for oversensitivity to light may be that when a bright light shines in the eye, there is normally a rapid contraction of the pupil to reduce the amount of light entering the eye. In ME/CFS, the light reflex may be delayed, or inadequate, due to faulty brain circuits or to weakness of the pupil constricting muscle in the iris.
Pain in the eyes
A condition of 'dry eye' is not uncommon in middle age and dry eye can cause severe pain. Artificial tears and lubricating ointment may help dry eyes, as does taking extra essential fatty acids. A few people with dry eyes may have a more widespread condition called Sjogren's syndrome, in which other glands are affected, and saliva dries up. This is thought to affect a small number of chronic MEE/CFS patients.
Less common, but more serious, are conditions which aching, pain, and redness, plus reduced vision. These require itmnediate referml to an eye clinic - a likely cause is uveitis, inflammation of a layer of the eyeball. Uveitis may rarely occur as well as a nonspecific immune response, similar to that in rheumatoid arthritis and ankylosing spondylitis.
Lastly, a mention of floaters, the bits of cobweb floating across the field of vision, more noticeable when looking at the sky. These are harmless, though annoying and happen more often if the subject is tired, also with increasing age. They are fragments of condensed coliagen in the jelly inside the eyeball. It is not known whether floaters are more common in ME/CFS than in other illnesses, or if people ue just more aware of them when unwell.
Reprinted from Emerge, Spring 1998.
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