Fine-tuning refractive outcomes before cataract surgery
Symposium will help surgeons get deeper insight in IOL power calculation. Dermot McGrath reports
Nino Hirnschall MD
Surgeons looking for valuable pointers to navigate the maze of current IOL designs and concepts and help improve their postoperative refractive outcomes will derive a lot of benefit from the symposium “Optimizing Your Refractive Outcomes Before Cataract Surgery” as part of the 25th ESCRS Winter Meeting Virtual 2021.
“This symposium will not only help surgeons to get a deeper insight in IOL power calculation but will also provide a peek into future developments,” said Dr Nino Hirnschall, who will be co-chairing the symposium with Dr Adi Abulafia.
The presentations from leading experts will provide a timely snapshot of a spectrum of key issues in fine-tuning refractive results, including optics and ray tracing, biometry, IOL power calculations, toric IOLs and extended depth of focus (EDOF) lenses.
While the technology has evolved, the fundamentals of hitting the target refraction has not altered, noted Dr Hirnschall.
“Many new different intraocular lens concepts have been developed over the years, treating corneal sphericity, astigmatism and even presbyopia. However, all these IOL concepts have one thing in common: if the desired target refraction is not met, visual quality without spectacles will be poor and the patient’s satisfaction will be low,” he said.
With this in mind, Dr Hirnschall said it is crucial to improve the prediction of the post-operative manifest refraction and to understand the underlying principles and recent developments in different associated fields.
“These fields include the understanding of the optics of different types of IOLs, biometry and IOL power calculation in regular, astigmatic and post-refractive eyes,” he said.
Although a lot of progress has been made in recent years in terms of improved biometry and better calculation formulae, there is always scope for further improvement, believes Dr Hirnschall.
“The old problem of the prediction of the post-operative lens position is still not solved. Modern formulae use more complex approaches to predict this post-operative IOL position, but refractive surprises do still exist. One approach we are working on is to use intra-operative OCT measurements of the aphakic eye. Therefore, we measure the position of the anterior lens capsule and use that as a prediction factor of the post-operative IOL position. The results are promising, but refractive surprises are still not eliminated,” he said.
Another problem, explained Dr Hirnschall, is the measurement of the cornea, which is particularly critical for toric IOLs
“Modern OCT devices combined with ray tracing have been shown to improve the results. In my opinion, toric IOL power calculation will improve due to better measurement techniques including the entire cornea,” he said.
With multiple IOL choices now available to fit the refractive needs of patients, patient education is probably more important than ever, said Dr Hirnschall.
“Chair time with the patient increases, as more different concepts have to be explained. Choosing also becomes trickier for the patient because of the range of choices. Selecting any IOL invariably involves an optical compromise. So, it is beneficial to start with explaining what a monofocal IOL provides and then explain the other concepts telling what a patient wins or loses with each lens. A second important factor is that IOL power calculation is crucial and a refractive surprise is always possible, no matter what kind of IOL is used,” he concluded.
Optimizing Your Refractive Outcomes Before Cataract Surgery, Saturday 20 February, 10.45 a.m – 12.45 p.m.