Accurate Eye Operations Using Lasers and OCT

3-D OCT projection of an fs laser membrane cut (symbolic laser focus in red). The membrane in blue is only 300 µm from the prepared porcine retina in brown. Individual images from the middle show the geometry. (Source: LZH)

3-D OCT projection of an fs laser membrane cut (symbolic laser focus in red). The membrane in blue is only 300 µm from the prepared porcine retina in brown. Individual images from the middle show the geometry. (Source: LZH)

Several laser-based operations are already established for correcting defective vision. However, this highly precise and yet gentle method cannot be used yet for presbyopia and for adhesions on the retina. In the project IKARUS, Laser Zentrum Hannover and four project partners have combined femtosecond laser technology with optical coherence tomography as well as adaptive optics, to expand the range of laser surgery.

In the established femtosecond laser-assisted in situ keratomileusis (fs LASIK), the cornea is cut open using the laser to subsequently correct the defective vision. In order to treat presbyopia however, the tissue has to be cut deeper. The scientists at the LZH and their industrial partners use an fs laser for precisely cutting the lens, creating slip planes and thus making the lens more flexible.

This treatment becomes only possible through an effective visualization of the eye tissue. For this, the Image Guided Laser Surgery Group of the Biomedical Optics Department of the LZH has adapted an OCT imaging unit from Rowiak. With this and a special software it is possible to image the cutting of the eye as well as the laser beam delivery during the operation. Within the project cuts into the eye have already been done without damaging neither the front nor the rear part of the lens capsule. In current clinical studies, Rowiak is further examining this process.

In order to remove retina adhesions, currently the eye must be opened and the vitreous body removed. The scientists at the LZH have integrated adaptive optics into an fs laser system, to be able to cut close to the retina. First results have already been established on the retina of pig eyes: with this system, model membranes only a few hundred micrometers away from the retina have been cut; the retina tissue directly behind it showed no noticeable damage.

In the project “Innovative cataract, presbyopia and retinal treatment using ultrashort laser pulses”, the following partners apart from LZH and Rowiak, both Hanover, Germany, as the system manufacturer have been involved: Qioptiq Photonics, Göttingen, as optics designers, Arges, Wackersdorf, for laser scanner systems, and Laserforum Cologne for clinical consulting and for measuring of the eyes. IKARUS was supported by the German Federal Ministry of Education and Research BMBF within the research alliance “Ultrakurzpulslaser”. (Source: LZH)

Link: Projekt Innovative Katarakt-, Altersweitsichtigkeits- und Retinabehandlung mittels Ultraschnellem Laser IKARUS, research alliance “Ultrakurzpulslaser”

 

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