OSN Europe: Optimizing outcomes of refractive cataract surgery: Are we there yet?

ByRichard B. Packard, MD, FRCS, FRCOphth

by Richard B. Packard, MD, FRCS, FRCOphth

It is now more than 50 years since the first attempts to carry out biometry were made using an ultrasound A-scan. As we can see from the cover story in this issue, there have been huge advances in the technologies available to ophthalmic surgeons. However, as said by the surgeons interviewed on this topic, results are still not as good as we would like. Data from large national studies show a surprisingly low percentage of patients achieving emmetropia. Although it is suggested that there may be factors to explain this, such as comorbidities and low use of toric IOLs, these results are still disappointing.

By and large, the use of ultrasound, except for the most extreme cataracts, is no longer needed. In a study of multiple different devices using a range of technologies, the new IOLMaster 700 (Carl Zeiss Meditec) and OA-2000 (Tomey) seemed to be able to produce a satisfactory reading with almost all eyes regardless of cataract density. Even with this level of success in measurement, there are issues that may confound the achievement of the desired outcome. While the actual axial length measurements are consistently accurate, particularly with the IOLMaster 700, other measures are needed to populate the formulae used to calculate IOL spherical and cylindrical power and meridian of astigmatism. As has been shown in many studies, getting accurate keratometry can prove elusive, and even when multiple devices are used, there may be inconsistency, which can be confusing. Even if the corneal power measurements are accurate and the axis of astigmatism is clear, correct IOL positioning and lack of postoperative IOL movement are essential.

Richard B. Packard

There are now devices available to assist in getting the toric IOL where it should be without the need for crude ink spots. They can be used preoperatively, such as the Callisto (Carl Zeiss Meditec) and Verion (Alcon), to capture images of the eye, which are then used intraoperatively with a head-up display for the surgeon to place the IOL in the correct meridian. This should increase the accuracy and efficacy of toric IOLs.

There seems to be some disagreement between surgeons on either side of the Atlantic about the use of intraoperative aberrometry to determine IOL power for sphere and cylinder with devices such as ORA (Alcon). Most of the European surgeons quoted in the article are largely skeptical about the help that may be afforded by this type of device in relation to improved accuracy and interference in work flow. There certainly can be difficulties in preparing the eye for measurement in the aphakic state relating to the pressure of the speculum and the depth of the anterior chamber due to viscoelastic use. There is also the issue that you may have to change the anticipated IOL, particularly if multifocal and/or toric IOLs are used, and thus there is a requirement for a huge lens bank.

Finally, there is the issue of how we might predict where in any given eye the IOL will finish up, and this is what in the end will prevent us, as surgeons, from batting 100% despite all these new and ingenious devices.

For more information:

Richard B. Packard, MD, FRCS, FRCOphth, OSN Europe Chairperson of the Editorial Board, can be reached at Arnott Eye Associates, 22a Harley St., London W1G 9BP, England; email: eyequack@vossnet.co.uk.

Disclosure: Packard reports he is a consultant for Alcon, Excellens and Shire.

Click here to read the commentary by Richard B. Packard, MD, FRCS, FRCOphth, published in Ocular Surgery News Europe Edition, June 2015.