REFRACTIVE TARGET

We’re getting closer and closer to the best possible surgical results regarding refractive target after cataract surgery, Stephen Lane MD, Minnesota, USA, told the XXXIII Congress of the ESCRS in Barcelona, Spain.

His presentation, entitled “New & Precise Technologies to Evaluate Astigmatism”, described several commercially available machines that can help cataract surgeons achieve the desired results.

“Each modality provides different measurements, so we have to take this into consideration when planning surgery. No one system is perfect, and there are variabilities between the measurements of each one. But when the results are all different, you can tell your patient, ‘We have the best equipment available, and they’re each telling us something different. So it’s possible that we’ll have to come back to perform a second procedure to perfect the result’,” he said.

For example, the Cassini uses multicoloured LED point-to-point ray tracing, combined with second Purkinje imaging technology and high-resolution images utilised for surgical guidance. Second Purkinje reflections are present on the posterior cornea. “Cassini allows you to import directly to Truevision, which is very convenient,” said Dr Lane.

Alternatively, the Galilei combines Placido-disk function with a dual-Scheimpflug analyser and ray tracing through the anterior and posterior corneal surfaces, leading to more accurate representations of total corneal power, he said.

Dr Lane next discussed the Verion Image Guided System, a comprehensive astigmatism planner that is not only a measurement guidance tool, but also includes a microscope-integrated display.

He pointed out what he considers to be a very useful feature in the interface: the astigmatism slider bar, which allows surgeons to select their preferred balance of astigmatic correction between toric intraocular lens (IOL) power and relaxing incisions in a single calculation.

WAVEFRONT ABERROMETRY DATA

The ORA System with VerifEye, the last system discussed, uses wavefront aberrometry data in the measurement and analysis of the refractive power of the eye.

“It has a real-time, intraoperative refractometer and a working algorithm supported by a large clinical database of more than one hundred thousand cases,” said Dr Lane.

“And now, the question that you may want me to be able to answer definitively is, ‘Is there a gold standard?’ While many of these tools give us excellent information, the most important factor is the surgeon’s capacity to gather the correct information from what’s available and use it in the best possible way to achieve great outcomes,” asserted Dr Lane.

Stephen Lane: sslane@associatedeyecare.com