CASSINI and LENSAR revolutionize cataract surgery

“For a passionate eye surgeon like me, these new technical options offered by LENSAR in combination with Cassini, that is to literally ‘tailor’ cataract surgery, are a huge progress. I do not want to keep my patients from these possibilities.”

Dr. Detlev Breyer

More and more patients are making use of the possibility to have their astigmatism corrected by toric intraocular lenses (IOL) or toric multifocal lenses (MIOL). Nevertheless, according to a survey performed by DGII, toric IOL only accounted for 3.1% of all IOL implanted in 2014. This might be due, among other things, to the fact that the calculation and exact positioning of toric lenses are quite demanding. Dr. Breyer specializes in this field and developed auxiliary devices and described techniques that facilitate implantation some years ago. He even was one of the first surgeons to implant them by means of minimally invasive microincision surgery.

Since August 2015, we have been one of two refractive centers in Europe to offer an improved laser surgery of cataract and presbyopia that could not be more individual. This possibility is provided by a new technique of corneal diagnostics, a so-called corneal topography using the new Cassini color LED shape analyzer. The term “topography” comes from the Greek words τόπος tópos (place) and γράφειν grafeïn (draw, describe) and means site sketch or site map. The Cassini corneal shape analyzer measures the anterior and the posterior surfaces of the cornea and visualizes them like a relief by means of 672 color-coded LEDs in red, green, yellow, and blue arranged in exactly defined patterns. A “corneal mirror image” is assigned to every spot. Cassini identifies astigmatism and even the smallest high-order aberrations from the normal surface of a sphere precisely and reproducibly with an unprecedented accuracy of less than 1 μm.

Subsequently, this data is fed in LENSAR’s Streamline laser system by wireless transfer. By the way, the LENSAR^® laser is the first cataract laser to offer this function since the update of its “Streamline” laser system received clearance from FDA in spring and the CE marking in June 2015. The system visualizes the degree of opacification of the natural lens (cataract density) exactly and calculates adapted patterns according to which the lens is fragmentized using laser energy to enable a gentler removal by the surgeon. The true axis of astigmatism presented by Cassini is marked by the laser in a way to enable the surgeon to align the artificial lens congruently later. This possibility perfects the implantation of a toric lens since, by its very nature, laser marking is far more precise than the manual marking used so far.

If mild astigmatism is found during diagnostic examinations, the program suggests arcuate corneal incisions using the laser for correction. More pronounced astigmatism must be corrected by so-called toric lenses. Toric lenses are shaped like the counterpart of astigmatism in order to compensate for it. This procedure, however, can only be successful if the lens is implanted exactly in the axis of astigmatism. For doing so, the cornea was simply marked up to now. Thus, despite this marking, the exact positioning remained one of the greatest challenges for the surgeon. Here, Cassini offers a very intelligent solution: it orients itself by the iris of the person, which is as individual as a fingerprint, in order to recognize the eye and shows the surgeon the previously measured axis of astigmatism both in the laser and under the microscope very precisely. This facilitates arcuate incisions or the orientation of the toric lens considerably and reduces inaccuracies to a minimum.