Now that the early
mobility problems of my Parkinson’s are largely under control due to the
medication, a new problem has started to take centre stage: my eyesight.
A quick Google search
reveals that perhaps 15-20% of Parkinson’s sufferers have vision problems. In many cases these are brought on by dry
eyes – because of the reduced blink rate.
My problem, on the
other hand, is diplopia, or double vision.
Put simply, beyond one or two metres I see two of everything. Two sets of people walking down the street,
making the morning commute tricky. Two
whiteboards in the meeting room. And
double sets of lane markers and headlamps on the motorway. No doubt people on the tube think I’m a
weirdo with my strange gaze and my expressionless, robotic face…
It started gradually
about two years ago, coinciding with the early symptoms of the other thing, and
got steadily worse until, around Christmas time, I realised that I really needed
to stop driving. The diplopia has now
largely stabilised to a point where I pretty much have it all the time. You’ll be pleased to know I have largely
stopped driving, partially thanks to the joys of Uber. And when I do need to drive I wear a pair of
glasses I made up with the left eye obscured.
This is not amazing but it works, and as far as I know is legal.
After seeing three
specialists – an ophthalmologist, an orthoptist and an eye surgeon – I have
more or less got to the bottom of the issue.
Time for another quick
science lesson.
There are three pairs
of muscles that control each eye: three on the top and a matching three on the
bottom. When one of these muscles is
slightly weak, the natural tension in its opposite member pulls the eye in one
direction, leading to a squint. My
specific problem is with the left superior oblique muscle. This means the muscle in my left eye on the
inside top. My left eye transmits an
image to my brain that is out of line with my straighter right eye.
It’s actually not an
uncommon problem, but typically our muscles and our brains compensate for
it. In my case I’ve probably had it
since birth and always managed but now I am no longer able to adjust. The interesting thing is that among the
specialists I have seen, opinion is split as to whether this is caused by my
Parkinson’s or just natural degradation with age. As I am starting to learn, medical science is
riddled with uncertainties.
Now for the scary bit.
Normally this can be
solved with prisms in a pair of glasses, which can move one of the images
vertically or horizontally until they match.
But in my case, unfortunately, the inside muscle also causes torsion,
i.e. rotation of one of the images. And
no prism can correct for that.
So I have two options:
live with it (assuming it doesn’t get better with time – unlikely) or have eye
surgery…
I went to see an eye
surgeon, Mr A, who talked me through the procedure. It only takes about 45 minutes under general
anaesthetic and involves cutting one of the muscles and re-stitching it in a
new place. Significant vision
improvement is seen in about 75% of cases and there seems to be little downside,
other than a week or so off work. I
guess in the worst case I still have my right eye to fall back on – I got Mr A
to confirm he wouldn’t touch that one!
I provisionally booked
myself in for surgery in June. £3,500
but hopefully the insurance will pay.
However, I am unsure
whether to go ahead. The reason is my
nervousness about general anaesthetic.
The risk of death in surgery is extremely low. But I’ve heard a number of anecdotes about
postoperative cognitive dysfunction. For
example, my own mother-in-law went in for a routine hip replacement and came
out suffering from Alzheimer’s.
Presumably the surgery didn’t cause the Alzheimer’s but it certainly
exacerbated it.
I did an internet scan
for relevant research papers.
Postoperative cognitive dysfunction is a recognised condition but my
profile is low risk. However, I also
found out that different anaesthetics are often needed for Parkinson’s patients
due to their medication. Although I
couldn’t find any scientific evidence of increased risk because of my disease,
I remain uncertain.
Perhaps I will opt for
local anaesthetic, but will that traumatise my brain even more?
I need a second
opinion from The Professor. Luckily, I
am due to see him, or rather two of him, in about a week’s time.
