Godts et al: Binocular Vision in Chronic Fatigue Syndrome

[mango]

Binocular Vision in Chronic Fatigue Syndrome

Godts D1, Moorkens G2,3, Mathysen DG4,2.

Author information
1 From the Antwerp University Hospital, Department of Ophthalmology, Edegem (Antwerp); godts@uza.be.
2 University of Antwerp, Faculty of Medicine and Health Sciences, Wilrijk (Antwerp).
3 Antwerp University Hospital, Department of Internal Medicine, Edegem (Antwerp), Belgium.
4 From the Antwerp University Hospital, Department of Ophthalmology, Edegem (Antwerp).

Am Orthopt J. 2016 Jan;66(1):92-97.

Abstract
INTRODUCTION AND PURPOSE:
To compare binocular vision measurements between Chronic Fatigue Syndrome (CFS) patients and healthy controls.

METHODS:
Forty-one CFS patients referred by the Reference Centre for Chronic Fatigue Syndrome of the Antwerp University Hospital and forty-one healthy volunteers, matched for age and gender, underwent a complete orthoptic examination. Data of visual acuity, eye position, fusion amplitude, stereopsis, ocular motility, convergence, and accommodation were compared between both groups.

RESULTS:
Patients with CFS showed highly significant smaller fusion amplitudes (P < 0.001), reduced convergence capacity (P < 0.001), and a smaller accommodation range (P < 0.001) compared to the control group.

CONCLUSION:
In patients with CFS binocular vision, convergence and accommodation should be routinely examined. CFS patients will benefit from reading glasses either with or without prism correction in an earlier stage compared to their healthy peers. Convergence exercises may be beneficial for CFS patients, despite the fact that they might be very tiring. Further research will be necessary to draw conclusions about the efficacy of treatment, especially regarding convergence exercises. To our knowledge, this is the first prospective study evaluating binocular vision in CFS patients.

KEYWORDS:
Chronic Fatigue Syndrome (CFS); accommodation; binocular vision; convergence

https://www.ncbi.nlm.nih.gov/pubmed/27799582

 

[trishrhymes]

How odd, and interesting. I wonder

1. Why they chose to study CFSpatients in particular
2. Whether they have done the same for any other condition
3. What biology they think might be causing this.

Any idea?

I guess I should read the whole paper but it's behind a paywall.

 

[RogerBlack]

I've noticed this - when I'm particularly tired, binocular vision is hard.
No need to get exotic on the biology - just everything takes more neurological effort when tired, and stuff gets dropped on the floor that would normally be considered essential, in order to just keep on pretending to be human and not a carpet.

 

[worldbackwards]

I think it's something to do with fatigue in the eye muscles. My own vision has been affected since I've been ill, to the point of double vision at its most serious.

 

[OverTheHills]

Since ME I cannot wear polarised sunglasses without getting migraine, and several others have the same issue.
So it looks like we have both muscular and neurological (processing two slightly different images into one) issues affecting our eyesight.

 

[Deepwater]

I have visual problems too. Very shortsighted to start with, so it's a pain. When I'm feeling bad, particularly, being out in large spaces like shopping malls is confusing, everything seems a jumble. My sense of depth often badly affected - I can't tell how far away the ground is. Had convergence problems even in my 20s, in the years after glandular fever. Optician gave me convergence exercises. I did them religiously but they didn't help - just made my eyes hurt and my brain feel sick.
Optician's appointments are hard. My eyes get too tired to keep doing what they're asking of me.
I miss the good 3D vision. Used to be ace, and I got a lot of aesthetic pleasure from that sense of spaces behind spaces in forests, cathedrals, etc.

 

[IreneF]

I'd rather have CFS/ME resources go toward something more fundamental than binocular vision.

 

[RogerBlack]

I'd rather have CFS/ME resources go toward something more fundamental than binocular vision.

This assumes that a cure will be rapid.

Many people find managing their energy levels really hard, and would like a concrete simple and rapid test that can be used every 5 minutes to work out if you are just feeling tired, or you're pushing too far.

ME/CFS would (for me) be much more managable with a little sensor that went 'bing', which was clinically proven, and could even be used as evidence that you could refer care or other professionals to for reasons why you were not able to do things.

I note the many million dollars spent on XMRV, which was basically wasted.
Picking 'obvious' routes to a cure, which may not lead to one, and neglecting symptom managment completely can destroy quality of life.
There has been almost no research into the 'trajectory' of PEM for example - cognitive, emotional and physical triggers, onset delay, persistance, long-term changes.

This research could have been done in 1995, and completely cut CBT off at the knees before it started as it would have been much more clearly physical.
As far as I can see, the early ME/CFS literature generally doesn't define PEM as much that is very clearly different from 'feeling overly tired after exercise'.
This made it way too easy for the fear-avoidance crowd to leap in.

 

[Forbin]

I think this is actually pretty important. It may well bear on everything from dizziness, to loss of depth perception, to feelings of "unreality." Basically, it seems like ME may either be inducing "strabismus" (the inability of both eyes to work together), or it is reducing the ability of ME patients to compensate for pre-existing "latent strabismus" (i.e. strabismus that is only noticeable when one eye is covered).

One of the ways people compensate for conflicting images from each eye is to suppress the image from the less dominant eye. This create more-or-less monocular vision, interfering with depth perception.

People also have something called "fusional reserve," which is the brain's capacity to deal with errors (up to a point) in the convergence of both eyes. It's somewhat like the brain's ability to fuse disparate images from the left and right eye into a single 3D image. In otherwise healthy individuals, fusional reserve is diminished by lack of sleep, tiredness or alcohol. It's conceivable that this threshold is lowered in ME patients.

A failure to properly converge the eyes could also induce a sense of motion, as convergence is one of the key cues by which we perceive the distance of near objects. This effect is used in 3D movies when something comes out of the screen at you. The angel of convergence of the focal point of the left and right images increases as the object approaches.

- - -
​

In the days between my triggering viral infection and the sudden onset of ME, one of the first things I started to notice were fleeting distortions in my visual field, as though I was looking through curved glass. I also began to notice that, when I was tired, or on the point of day-dreaming, my left eye would lose "lock" with the right eye and it would swing outward until I roused myself into state of greater alertness.

After the onset of ME, my most debilitating symptoms were unrelenting dizziness and a sense that I was constantly bobbing forward and back. This was diagnosed as an inner ear problem, but it seems likely to have been associated in some way with my visual problems as well.

Your eye doctor tests for latent strabismus when he tells you to cover one eye with a shield and then to remove it. The covered eye may have lost "lock" with the uncovered eye, and he can see if two eyes struggle to return to lock when you remove the shield.

I'm familiar with this because, 10 years after the onset of ME, an ophthalmologist told me that I had severe latent strabismus in both eyes.

No eye doctor ever mentioned that to me prior to the onset of ME.

 

[me/cfs 27931]

Interesting study. I had prism glasses and eye exercises from about age 6-10 (for strabismus). The eye exercises seemed to help.

Eye issues are one of the most work-disabling features of this disease. Eye problems for me persist even during disease remissions when other symptoms subside.

My optometrist currently recommends against prisms. I will have to revisit this issue with him.

Two past articles on eye issues in ME/CFS:

Vision-related symptoms as a clinical feature of chronic fatigue syndrome/myalgic encephalomyelitis? Evidence from the DePaul Symptom Questionnaire
http://www.meresearch.org.uk/our-research/completed-studies/vision-related-symptoms/

Visual Problems with ME/CFS
http://www.fightingfatigue.org/visual-problems-with-mecfs/

 

[Daisymay]

If the findings are highly significant, if they can be replicated could this be used diagnostically along with other things I wonder?

 

[soti]

I periodically have to do the orthoptics convergence stuff (about every 5 years or so). It helps my eye fatigue.

 

[Effi]

The CFS/ME Medical Centre in Amsterdam has decided to add an eye test to their standard list of tests, based on the info in this paper. Not sure if it is done for research purposes, or for diagnostic purposes. They are trying to distinguish between convergence weakness as a consequence of ME, and convergence weakness as the cause of a patient's exhaustion (which would mean they don't have ME to begin with).

Convergence weakness, a supplement to our diagnostics

We know that ME patients cope badly also with non physically straining work.
We already did measurements of the delay in the thinking process with clear differences with healthy controls, but that does not really explain the exhaustion.

Maybe an article by Godts, Moorkens and Mathysen from the University of Antwerp can help us. They showed that ME patients may have a problem with eye alignment.

The result is fatigue, tired eyes, eye pain, a pulling feeling around, blurry or double vision, the feeling that the letters move and losing track of sentences.

When reading something at close proximity, the eye must focus (accommodate), the eyes turn towards each other (converge) and the pupil opening narrows (miosis). That convergence turned out to be a problem in 22 of the 41 ME patients and in 3 of 41 healthy controls. The accommodation was also significantly reduced, compared with healthy controls. The result is that work that does not seem to be tiring turns out to be exhausting.

We think that "to measure is to know", so we have expanded our research with an expert. We screen all patients for convergent insufficiency complaints with the Convergence Insufficiency Symptom Score and with a measurement of convergence. When combining complaints and deviating values in the measurement, we refer to optometric research by our expert.

We expect to find more convergence weakness in ME patients and possibly also see people who are tired because of convergence weakness and don't have ME.

Godts D, Moorkens G, Mathysen DG: Binocular vision in chronic fatigue syndrome. Am Orthopt J 2016, 66 (1): 92-97.

 

[Esther12]

The first thing that came up when I googled 'convergence exercises': https://www.wwl.nhs.uk/Library/All_...rcises_for_convergence_insufficiency816v3.pdf

I find the reading things close to me can trigger problems.

 

[Snow Leopard]

See also:
http://me-pedia.org/wiki/Visual_dysfunction

I'd rather have CFS/ME resources go toward something more fundamental than binocular vision.

For some of us the eye problems are a major symptom - for me eye pain and difficulty reading has become my worst symptom in terms of quality of life.

Additionally, specific eye symptoms means the lazy hypotheses of CFS being due to sensory defects or anxiety are falsified, and it may give clues to pathology.

 

[ash0787]

I noticed some differences but its hard to explain, on occasions its difficult to conceptualize 3D space correctly, and I often don't like seeing lots of reflections and multiple light sources etc, also sometimes when really tired I can make my eyes lose tracking entirely and just sort of vibrate, for some reason it seems to make me feel less tired

If you use VR though it will force binocular vision and seems to conserve energy, basically faking being in a pitch black room with just a TV as a single light source

 

[RogerBlack]

I wonder about flicker fusion frequency. (the frequency at which a flickering light appears solid)

http://www.tandfonline.com/doi/full/10.1080/00140139.2016.1242782

Nine measures were found to be significantly responsive over the 8-h period, including: ratings of perceived fatigue, postural tremor, blink frequency and critical flicker fusion frequency threshold.

https://www.ncbi.nlm.nih.gov/pubmed/24505277

However, significant differences were observed in the standing-position balance and CFF tests among the subjects, suggesting that psychophysiological indexes can reflect mental changes caused by workload to a certain extent. The CFF test was the simplest and clearly indicated the occurrence of workload influences on pilot performances after a simulated flight.

(I'm wondering as CFF is in principle moderately easily and cheaply measured, and takes ~0 effort to do. - look at a light and say if it's flickering.)

 

[RogerBlack]

Skimming the paper in question.
The CFS selection criteria look not unreasonable.
six months illness, four of sore thoat, tender lymph nodes, muscle pain, multi-joint pain, PEM, unrefreshing sleep, impaired memory or concentration.

The ocular tests are simple one-off tests at a point in time, and I get the impression that the whole procedure is quite brief.

There is no mention of if they explored the correlation between severity and optical shortcomings.