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Saturday / January 29.
HomemicontactVisual No-Man’s Land

Visual No-Man’s Land

Professor Nathan Efron recounts his experience in ‘visual no-man’s land’ – a particularly stressful phase of his ophthalmic journey of retinopexy, cryopexy, vitrectomy and IOL surgery attributed to extreme surgically-induced anisometropia.

Business consultant Michael Jacobs reflects on lessons learnt from a high profile career in optics, giving mivision readers his ‘two cents worth’ on the future for independent optometry, Australian-style. In this article he talks about how to mitigate the isolation of independent practice.

Three days after my left eye vitrectomy it was time to return to the clinic for a post-operative evaluation. At this stage I still had a large air bubble in my eye, but I was starting to see the world over the top of the bubble. The tech measured my visual acuity as R 6/5-3 L 6/18+1. Intra-ocular pressures were R 13 L 7 mmHg. I then saw Mike (the optometrist who works in the clinic), who had a good look around with the Volk lens and declared all looked as it should three days after a vitrectomy. It was not possible to perform optical coherence tomography (OCT) at this stage as the bubble was still too large. Mike said that he would see me again after two weeks and then both he and Bill (my ophthalmologist) would see me after four weeks.

Ten days after my vitrectomy, when my air bubble was very small, I went to Suzanne’s optometric practice to see if we could do OCT. Visual acuity was now R 6/5 L 6/9, and my intra-ocular pressures were R 14 L 14 mmHg. We could in fact get a good OCT image of my left eye, which revealed an intact retina, albeit with a little oedema at the macular area, which was not unexpected. Using the anterior eye attachment on the OCT, central corneal thickness was measured at about 530 µm in each eye.

I recalled from my optics training 40 years ago that aniseikonia is significantly reduced with contact lenses

Sensing that I might be getting an IOL placed in my left eye sooner rather than later, I asked Suzanne to get a good handle on my level of corneal astigmatism. The Nidek Autokeratometer/autorefractor showed a 1.25D corneal cyl. The Medmont Topographer indicated a 1.20D cyl and then 1.00D cyl on a repeat reading.
I made a careful note of this for subsequent comparisons with what Bill’s team would find when I would be eventually worked up for IOL surgery.

Galloping Myopia (Again)

When I saw Mike again two weeks later (now 17 days post vitrectomy), we discovered that there had been a 1.50D myopic shift in my operated left eye. This also was not unexpected, as a similar myopic shift had occurred following my right eye vitrectomy. My refraction was now R -1.25/-1.25 x 90 L -7.00/-1.50 x 170; visual acuity was measured as R 6/6-2 L 6/5-2 and my intraocular pressures were R 13 L 11 mmHg. Early nuclear sclerosis was noted in my left crystalline lens. He also performed OCT and declared that
all looked fine.

Now visually, I was facing somewhat of a dilemma. The large myopic shift in my left eye meant that I had to somehow deal with 5.50D of anisometropia. With the full correction in both eyes in a trial frame, I was unable to fuse the two images to achieve binocular vision. I also noticed that everything seemed about 20 per cent smaller when looking with my highly myopic left eye compared with my right eye. So how was I going to cope visually?

Well, there was no easy answer. Mike didn’t bother discussing this with me, presumably because he knew I was an optometrist and would be well aware of all possible options. I recalled from my optics training 40 years ago that aniseikonia is significantly reduced with contact lenses. However, I didn’t want to wear a contact lens in my recently operated left eye. So, one option would be to wear a distance contact lens in my right eye, leave my left eye uncorrected, and pop on a pair of +2.00D ready readers for close work. This worked to some extent, but I felt uneasy using my right eye for distance vision given that I had been using this eye for near vision for the past decade with monovision contact lenses.

After putting up with this for about a week I became fed up and decided to try something different. It was now three weeks since my left eye vitrectomy and I felt confident to insert a contact lens in my left eye. So I managed to acquire a box of daily disposable contact lenses to use as a left eye distance correction, and wear nothing in my now-pseudophakic right eye which was corrected for near. And true to what I had learned in Optics 101, there was no noticeable aniseikonia.

A remaining problem was what to do in the evenings. By this stage I was back at work and I did not want to over wear the contact lens in my left eye. I am an early riser, so by 5pm I had been wearing my contact lens for about 12 hours. I didn’t want to have a spectacle lens made up to correct my left eye as it was probably going to keep getting more myopic. I already had glasses made up that corrected my right eye for distance, but I was unable to wear these due to eikonic effects and general visual disorientation, even with the left lens removed. So what to do now?

The only real option was to wear my glasses with a tissue in place over the left lens that would block the view from that eye. However, this was uncomfortable as I found the tissue irritating. At this point Suzanne recalled that at work she had a specially designed occluding patch to cover one eye of a spectacle lens for children undergoing orthoptic treatment.

Suzanne brought the patch home the next day and it worked perfectly. However, the front of the patch had brightly coloured stripes, a design that probably works fine by way of appeasing children, but one which was not really suitable for wearing in public as an adult. Anyway, I decided, I could get through the evenings OK with this solution for now…

IOL Replacement Sooner Rather than Later

Five weeks after my left eye vitrectomy I fronted up to the clinic, this time to see Bill. This was the first time I would be seeing him following the vitrectomy. After being worked up in the usual way by the tech and one of the attending optometrists, I met with Bill and bemoaned my discomfort at being in ‘visual no-man’s land’. He fully understood my dilemma.

Bill carefully examined my eyes with the good old Volk lens, and confirmed that all was fine. After scanning though my clinical records he paused, looked me in the eye and asked, in hopeful anticipation, if the flying angel of death was still noticeable in my right eye. “Alas, it’s still there,” I replied to his disappointment.

Bill went on to say that for refractive reasons alone it was worthwhile going ahead with IOL surgery in my left eye right away. He added that I would need to have this procedure sooner or later as a posterior subcapsular cataract would inevitably form following my vitrectomy. Although that process can take up to 18 months, there was no requirement to wait this length of time. I queried whether a period of five weeks was too soon after a vitrectomy to be having another operation, but Bill assured me that my eye was now quite stable and proceeding with IOL surgery would not pose any problems.

It was Wednesday, and we agreed to go ahead with surgery two days later, on the Friday. I was very happy with this decision, as I could now see the light at the end of the tunnel.

Before I knew it, I was handed over to the techs to have the usual pre-surgical work-up. There was a flurry of activity, but I insisted on writing down all corneal power findings. Both the Humphrey Autorefractor/Autokeratometer and Nidek Hand-Held Keratometer indicated astigmatism of 1.25D; the Zeiss IOL Master indicated 1.67D, and the Pentacam gave a value of 1.20D.

I was then handed over to the surgical administrative team, who gave me the usual briefing and information packages, and the now familiar warning not to engage in strenuous physical activity for a few weeks following surgery (nudge, nudge, wink, wink). I was also handed a single dose of mydriatic to instil in my left eye one hour before my surgical appointment time. Once again I asked for the earliest surgical slot, and this wish was granted.

The big challenge now was to try and choose an IOL that would render me perfectly emmetropic in my left eye. I was determined this time to fully involve myself in that decision-making process. The last thing I wanted was to end up with residual astigmatism, as occurred previously in my right eye following IOL surgery. Combining Suzanne’s earlier measurements and these findings, my corneal astigmatism could be anywhere between 1.20D and 1.67D – over a half dioptre spread. Not a good start!

Anyway, Mike said that if Suzanne and I could come back to the clinic at the end of the day after his last appointment, he would be able to sit down with us and ‘negotiate’ a suitable set of IOL specifications.
We gratefully accepted his offer.

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.

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