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Saturday / March 2.
HomemicontactNot Waterboarding…Posturing!

Not Waterboarding…Posturing!

On three occasions during the course of his ophthalmic journey of retinopexy, cryopexy, vitrectomy and IOL surgery, Professor Nathan Efron was forced to endure a horrible procedure known as ‘posturing’.

The Saturday morning after my left eye vitrectomy, I woke up to great relief. Unlike my right eye vitrectomy six months previously, there was no appearance of ‘ink in the sky’ or any other visual phenomena that might suggest intraocular bleeding. I was aware of the large air bubble in my eye, but there was no brown haze like last time. Everything was bright and clear, albeit optically blurry as expected due to my high myopia and the presence of a large air bubble inside my eye. I could make out large objects, which had a shimmering appearance, like looking through water. I guess this is due to the fact I was partly looking through aqueous humour that was slowly beginning to fill my vitreous chamber.

At least my macula was attached and working, it appeared. I couldn’t really tell if I had another flying angel of death (my pet name for an annoying small blind spot in my right eye); that assessment would have to wait until the bubble resolved in 10 days to be sure.

Later in the morning I received the customary phone call from the tech at the eye clinic checking that everything was OK. I reported that I was fine, and that fortunately there was no repeat of the post-surgical intra-ocular bleeding that plagued my previous right eye vitrectomy. She reconfirmed my appointment for Monday morning, and wished me well with my posturing…

It didn’t take long to get used to watching doubly reversed cricket in the mirror, and I would recommend this anti-boredom strategy to anyone…

Posturing Torture

For three days following a vitrectomy and epiretinal membrane peel, it is necessary to undergo a procedure known as ‘posturing’. Now, if the CIA is ever looking for a new method of interrogation to replace waterboarding, I would highly recommend posturing. It is a truly horrible business.

For the uninitiated, the theory of posturing is simply this: you have just had surgery performed on your retina, a very delicate tissue that is easily torn and has a propensity to detach from the back of your eye, leading to vision loss. The large air bubble inserted into your eye following a vitrectomy slowly gets replaced by aqueous fluid, but while the air bubble is present, it will always rise upwards because it is lighter than the surrounding fluid (Figure 1). It is desirable that the air bubble presses against the posterior pole (the very back of the eye) to hold the retina in place as well as temporarily sealing off small holes that may be present. This is especially important around the macular area, which subserves sharp vision. Thus, you have
to adopt a face-down posture.

The upward pressure of the air bubble against the retina is referred to as a tamponade. The tamponade effect gradually wears off over the next 10 to 12 days as the globe fills with aqueous, which is associated with a commensurate decrease in the size of the air bubble. After three days the bubble is no longer large enough to act as an effective tamponade.

My instruction was to adopt a head-down posture for 30 minutes every hour for three days while awake; that is, the rest of the Friday after my early morning left eye vitrectomy, and all day Saturday and Sunday. Given that I had already been through a right eye vitrectomy and repeat procedure in the same eye, I was now about to endure my third stint of three-day posturing.

Given the brutality of this procedure, anything one can do to alleviate the two key annoyances associated with posturing are worth contemplating. These two annoyances are (a) physical discomfort of the head, shoulders, neck and arms, and
(b) sheer boredom. I shall deal with these one at a time.

Alleviating Physical Discomfort

The body is not designed to support a head positioned parallel to the ground, so additional means of support are required. In discussions with the tech at the eye clinic prior to surgery, I was told that it was possible to hire cushioned frames that would sit on a low table and support my head as I leant forward to rest my chin and brow upon it. Alternatively, I could hire a full length padded bench with a face-sized hole, through which I would peer when lying face down on the bench. The alternative to using such appliances, I was told, was to simply lean forward and rest my head on my hands while looking down.

I chose the last option. After much trial and error, I figured the best set up was to sit on a firm chair, place a cushion on each thigh, rest my elbows on these cushions, and rest my head in my hands. Figure 2 shows me adopting this configuration for my very first posturing session following my left eye vitrectomy.

This approach was only partially successful, as I developed great discomfort at the base of my neck and shoulders, which worsened over the three days of posturing. I tried various iterations of this basic technique (different chair, more cushions, supporting my head differently etc.), but to no avail; no matter what I did, the discomfort persisted. It took about two weeks before my neck and shoulder soreness had completely dissipated. Also, for some reason my nose kept running when looking down.

Think about it. Thirty minutes of this every waking hour for three consecutive days. Horrible! The rest of my daily activities – eating meals, having a drink, inserting eye drops, going to the toilet, showering, checking e-mails, making telephone calls etc. – had to be crammed into the alternate ‘non-posturing’ 30 minutes each hour.

Figure 1. Theory underpinning posturing. When looking down, the air bubble inside the eye rises up within the partially fluid-filled vitreous chamber to press against the retina at the posterior pole of the eye, exerting a tamponade effect.

There is another aspect of posturing that is equally important – and that is, what do you do when sleeping, which amounts to about one third of your day? It is, of course, impractical to sleep face down… one needs to breathe! So, this means sleeping with either the left or right cheek against your pillow. I was instructed to sleep with my right cheek down. Sleeping in essentially one position all night is a real pain. You tend to want to shift around subconsciously when asleep, so to avoid this you kind of have to be half awake to ensure that you don’t change positions. Two restless nights ensued.

Dealing with Boredom

Gazing down at the floor for 50 per cent of the time over three days is no fun, so an anti-boredom strategy was needed. One option was to watch movies on an iPad on the floor below. This could have worked, but I didn’t feel like watching movies.

As it turned out, a cricket test match was under way, and I am a big cricket fan. But how could I watch TV when gazing downwards. I thought of using a mirror angled at 45 degrees, but figured that everything would be upside down. When I ruminated over this out loud to my family, my son Bruce said that if looked through a mirror facing a TV positioned behind me, then this would amount to a double–reversal of the image and the TV would appear normal and upright. How he figured this out I will never know. Bruce is in the third year of a combined law/psychology degree, and knows nothing about optics. Why couldn’t I, the optometry professor, have worked that out?

Figure 2. Posturing set up. My elbows rest upon cushions on my thighs and my hands support my head. A large mirror supported by two cushions and a wooden beam (to prevent slippage of the base of the mirror on the floor) is positioned between my legs and angled at 45 degrees, so that I can watch cricket on the TV positioned behind me. A box of tissues is on hand to wipe my runny nose.

So, I got hold of a small hand mirror and gave this a try. As it happens, Bruce was only half right. Everything does indeed appear the right way up, but the image is laterally transposed (i.e. left and right are swapped around).

Some Trivia for Cricket Tragics

I adopted Bruce’s suggestion by positioning a large mirror angled at 45 degrees between my legs, facing a large screen TV behind me that could be viewed beneath my open frame chair (Figure 2). Watching cricket like this for three days was enjoyable and certainly alleviated the boredom, but there were some interesting challenges…

Any text on the TV, such as the score strip at the bottom of the screen, was back to front and thus difficult to read. If you are a cricket tragic like me you will appreciate the following observations. Right hand batsmen and bowlers appeared left handed, and vice versa, and the Freemantle Doctor (refreshing afternoon ocean breeze over Perth) comes in from the east instead of the west. However, positions on the field as called by the commentators were ‘correct’, because of course all cricket positions are specified with respect to the positioning of the batsman’s legs. So, mid-off, gully, point, cover, silly mid-on, deep fine leg, square leg etc. all appeared in the correct location relative to the batsman. Similarly, a bowler’s off-spin and leg-spin appeared the right way around. It didn’t take long to get used to watching doubly reversed cricket in the mirror, and I would recommend this anti-boredom strategy to anyone (but especially cricket tragics) who has to posture following a vitrectomy!

For 12 days after my vitrectomy surgery, the air bubble inside my eye slowly reduced in size and eventually disappeared, but provided endless episodes of entertainment while it was there… but that’s another story, which I’ll tell you all about in my next blog.

Professor Nathan Efron is a researcher at the Institute of Health and Biomedical Innovation and School of Optometry and Vision Science, Queensland University of Technology. He is currently president of the Australian College of Optometry and vice-president of the International Society for Contact Lens Research.