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Saturday / April 13.
HomemicontactEeny Meeny Miny Moe

Eeny Meeny Miny Moe

In the closing stages of his ophthalmic journey of retinopexy, cryopexy, vitrectomy and IOL surgery, Professor Nathan Efron sits down in a conference room to negotiate IOL selection for his left eye.

After a whole raft of measurements were performed on my left eye in preparation for IOL surgery, Suzanne and I returned to the clinic to meet up with Mike. He ushered us into the conference room and laid out all the relevant record cards and instrument print-outs containing measurements of ocular parameters that would be used to choose an IOL of appropriate specifications.

Our aim was emmetropia. I already had an Acrysof IQ Toric IOL inserted in my right eye, so we were certainly going to stick to the same lens type. We needed to determine the parameters to input into the Alcon IOL online calculator for the Acrysof lens. The Holladay one, Holladay two and ‘SRK/T’ calculations all pointed towards a 13.50D lens. That was easy.

But now came the choice of cylinder power. You will recall that I ended up with an unwanted cyl of about 1.00D in my right eye, although this was not the final cyl as my refraction still had not completely stabilised in that eye. Three weeks previously Suzanne measured my corneal astigmatism on two different instruments, which revealed values between 1.00D and 1.25D. On the day of decision making, the techs recorded values ranging from 1.20D to 1.67D. So, with a total spread of 0.67D, how was one supposed to choose an appropriate cylinder power? I penned the following adaptation of an old children’s rhyme to express my frustration:

I sat there in stunned silence, almost unable to speak. Everything was very clear and I had to keep reminding myself that I was not wearing glasses or contact lenses

Eeny, meeny, miny, moe

Choose an IOL to go

First pick power, then a cyl

And guess the axis if you will.

After some discussion, we decided to rely on the results of the Humphrey Autorefractor/Autokeratometer for cyl power, and opted for a 1.25D cyl correction. We also factored in predicted surgically-induced astigmatism of 0.2D, as this is what Suzanne and I calculated had occurred for the right eye. So, the on-line calculator spat out this result: Acrysof IQ Toric IOL 13.50D SN6AT3 Axis 94. This would result in an anticipated residual cyl of 0.42D axis 95. Now I could look forward to my (hopefully) final eye operation in two days’ time.

Benefits of Forearm Curls

Admission time was 6.30am, so I rose at 5.30am to instil a drop of Cyclopentolate Hydrochloride 1 per cent into my left eye, as instructed. I was feeling very relaxed, as I was about to experience the same pre-surgical ritual that I had been through five times over the past year or so. I filled out the admission form, chuckling to myself as I yet again entered the instruction for theatre staff not to bump the operating table during surgery. So here we go: shoe covers, gown, red hat, two paracetamol tablets, blood pressures taken, finger prick blood glucose test, pre-surgical mydriatic and anaesthetic. All set.

Figure 1. Doing my forearm curls

I was quickly taken through to the operating theatre where the assisting surgeon was pottering around making preparations for surgery. I seized the opportunity and asked him to verify they were inserting the correct IOL power; he obliged and we both cross-referenced his pre-surgical notes with the label on the IOL container. All good.

The anaesthetist soon arrived and proceeded to examine my arm in search of a suitable site to insert the anaesthetic feed. While doing so he remarked to my surprise, “These are pretty healthy looking forearms you have, Nathan. Do you play some sort of sport?” I blurted out a quick answer to the effect that I try and keep fit.

But in fact, it goes further than that. Ever since being diagnosed with type 2 diabetes in my early 30s, I have maintained a strict regimen of diet, exercise, weight control and medication compliance. As part of all this, I do a one hour work out in the gym about four times per week, with each session being 50 per cent aerobics and 50 per cent weights. For the past couple of years, somewhat arbitrarily, I have been doing forearm curls to strengthen my wrists and forearms. This involves resting my forearm on my thigh while seated, and raising and lowering a 15kg dumbbell just by flexing my wrist (Figure 1). This exercise is repeated 12 times each side, and then done two more times (i.e. three sets of 12 reps).

I guess anaesthetists must spend a lot of time examining forearms, so when my anaesthetist commented on the healthy state of my forearms, I was particularly chuffed [this is a quaint British expression meaning ‘pleased’; I picked it up after having living in the UK for 16 years (1990–2005)]. All those forearm curls had been worth it, at least from an anaesthetist’s aesthetic standpoint!

Reassuring Buzz of the Phaco Machine

As soon as the anaesthetic was administered, Bill turned up and got straight into it. I seemed to be quite conscious throughout. I could hear the faint buzz of the phaco machine and at one point I heard Bill saying he was carefully positioning the IOL axis. Before I knew it, I was being wheeled into the recovery room. The procedure could not have taken more than 15 minutes.

After scoffing down my coffee, sandwiches and biscuits in the recovery room, the assistant surgeon checked my eye using a binocular indirect ophthalmoscope. He declared that all looked good. I was given the usual pack of drugs: Chlorsig – four drops a day for two weeks; Pred Forte – four drops a day for four weeks, then two drops a day for another four weeks; Panadeine (500mg paracetamol and 10mg codeine phosphate) – to be taken if I was experiencing pain; and Lacrilube – up to four times a day as required if my eye felt dry and/or gritty.

I departed one hour and 40 minutes after entering the pre-surgical area. That’s what I call efficiency! My eye was starting to get a little uncomfortable, so I took two Panadeine tablets every four hours throughout the rest of the day. There was considerable tearing until early afternoon. By early evening my vision had gradually begun to return, but my pupils were still widely dilated, resulting in broad halos around lights.

By mid-evening I was getting very tired, so I decided to go to bed early. It had been a long day. As I dozed off, I wondered what my vision would be like the next day, as a bilateral pseudophake with clear vitreous chambers and pupils back to their normal size…

A Whole New Visual World

I woke up the next morning to a beautiful sunny day on the Gold Coast, with a cloudless, stark blue sky. After a quick bowl of cereal, Suzanne and I brewed up a nice frothy cappuccino and settled down on our back portico, overlooking a large still lake with smart houses lining the opposite bank about 200m away.

I sat there in stunned silence, almost unable to speak. Everything was very clear and I had to keep reminding myself that I was not wearing glasses or contact lenses. We have a beautiful vista out onto the lake and I was viewing all this unaided, on a glorious day, without any optical aids. I had not had a visual experience like this since I was about 14. It was indeed an emotional experience. I just sat there for about two hours in awe of the wonders of ophthalmic surgery.

The tranquillity of this enticing visual experience was rudely interrupted by the telephone ringing. It was one of the techs from the clinic, making her usual next-day, post-surgical, follow-up phone call. I reported that all was fine, and we reconfirmed my appointment at the clinic on Monday.

I decided to do a rough and ready check of my refraction. I put on a pair of +2.50D ready readers, closed my right eye, and held some fine print about 40cm away. It was a little unclear, but became clearer when I held the print a bit closer to my eye. “That’s great,” I thought. The literature suggests that there is typically a myopic shift following IOL surgery, which resolves over the following few weeks. So if that happens to me, I thought, then maybe I will be heading for emmetropia.

But the big question was whether or not there was any residual astigmatism. The literature also suggests that it can take two or three months for a refraction to stabilise following IOL surgery, so I was just going to have to be patient…

Professor Nathan Efron AC 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.