Through my training and career, I’ve worked in 10 public hospital eye departments across Australia and New Zealand where an arbitrary threshold decides which patients are given toric IOLs for their astigmatism.
This threshold has usually required above two dioptres of corneal astigmatism. We know from large population studies that it’s rare to have this degree of astigmatism – and that residual, untreated astigmatism is detrimental to vision quality.
These thresholds meant, as a registrar, I never implanted a toric IOL. Use among trainees does appear to have improved since then. While teaching final year ophthalmology trainees from across Australasia, surveys indicated they had implanted toric IOLs in 1-2% of cataract surgeries before the end of their training.
However, in my private clinic where I have freedom to use appropriate toric IOLs for astigmatism, I use 85% toric versions of the various IOLs I implant. My toric IOL usage is not at all excessive. I’m not implanting toric IOLs in case of future development of astigmatism; I’m simply providing a refractive correction right now with as little residual refractive astigmatism as possible.
Why is there such a difference in refractive goals between the public and private systems? The best analogy for public hospitals is to imagine seeking glasses from your optometrist and being given a pair that only corrects spherical error for long or short sightedness but no cylinder correction of your astigmatism. Patients would immediately complain and return their glasses. You can think of other similarly ridiculous scenarios such as an orthodontist only straightening your upper teeth, or a plumber unclogging only the straight sections of plumbing.
A combination of factors have led to us only implanting toric IOLs in high astigmatism and this being acceptable.
The first common issue is cost. It’s true a toric version of an IOL costs significantly more than non-toric. On the scale of surgical prostheses, IOLs are cheap compared to artificial joints, and heart valves yet provide great improvement in quality of life. There have been plenty of cost-benefit analyses on toric IOLs which I won’t detail here, but basically the decreased need for glasses, lower falls risk and improved quality of life and productivity with toric IOL use, renders the added cost insignificant.
A major problem is the people who pay this extra cost for public hospital budgets don’t see the added benefit. Ophthalmology department budgets are limited yet can somehow cope with the escalating millions of dollars needed for intravitreal injections for macular degeneration, diabetes and vascular occlusions annually. Comparatively, lowering the arbitrarily set threshold for toric IOLs is a minor cost.
I’m fortunate to work in a public hospital department (The Queen Elizabeth Hospital, Adelaide) where we can implant toric IOLs without a threshold. In fact, we can implant trifocal toric IOLs without limit. This has developed through the immense work of our head of department, A/Prof Michael Goggin, and collaboration from IOL manufacturers, with special thanks to Zeiss.
This is a great model for examining what happens when cost is no longer an issue and artificial thresholds have been removed. Interestingly, there are still cases where an appropriate toric IOL version isn’t implanted. I know my colleagues well enough to understand this isn’t to create an artificial difference in quality to promote private surgery, nor to keep referring optometrists happy with patients still needing glasses.
Instead, my theory is there is still some hesitancy to implant low power toric IOLs due to uncertainty about dealing with potential problems. There’s also an apathy to do the best possible job, as for so long, leaving residual astigmatism has been acceptable. Anyone who implants low power toric IOLs realises this is a robust technology that works well and the need for further intervention is rare. The other side of this argument is that low power toric IOLs still haven’t been approved by the US FDA , as a clear visual benefit has not been proven in trials.
Unfamiliarity and uncertainty with toric IOLs would seem to be a driving factor of poor uptake in public hospitals. Further education, both from industry and colleagues, will be important in further improving uptake in departments like mine. Elsewhere, in departments with a threshold for toric IOLs, I simply ask surgeons to consider whether they would be happy for themselves or their family to be left with residual refractive error when the same operation could provide perfect unaided vision.
ABOUT THE AUTHOR:
Name: Dr Ben LaHood
Qualifications: MBChB PGDipOph PhD FRANZCO
Organisations: Ashford Advanced Eye Care and The Queen Elizabeth Hospital
Position: Cataract and refractive surgeon
Location: Adelaide, South Australia
Years in profession: 6
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