Feature Of The Week 3/7/10: OCT Guidance for Femtosecond Laser Treatment of Presbyopia
Feature Of The Week 3/7/10: Despite the clear and continually growing commercial success of Optical Coherence Tomography (OCT) in a wide range of clinical fields including ophthalmology, cardiology, and microscopy there remain few commercialized examples of OCT integrated with real-time surgical treatment procedures. However, those examples cannot be too far off based on some of the interesting advances in the OCT research world. One recent example was the demonstration of OCT guidance for femtosecond laser treatment of presbyopia which was demonstrated by The Biomedical Optics Department at the Laser Zentrum Hannover e.V. A short description and slide show of some of their work is given below.
Based on the Helmholtz theory the loss of accommodation is only due to the hardening of the lens. The accommodation apparatus (cilliar body and lens capsule) stays active. Therefore the concept of creating gliding planes in form of micro cuts inside the lens to increase or in best case re-establish the flexibility seems a promising tools to cure presbyopia.
An ultrashort pulse laser (fs laser) is especially suited for the creation of the micro cuts inside the lens based on the nonlinear interaction of ultrashort pulses and tissue, the so called photodisruption effect. Thereby arbitrarily three dimensional structures can be cut inside the lens. A suitable cutting pattern for the treatment of presbyopia was developed, the so called “steering-wheel”-pattern. This pattern comprises gliding planes in all directions in space and leaves the central field of view unaffected. While generation of cutting patterns inside crystalline lenses has already been presented as well as the optimum laser parameters have been choosen, a new combined optical setup for the cut alignment is shown here.
The aim of the project "The guided scalpel" is to build a combination of a surgical laser and OCT-imaging. By combining the two optical paths and using the OCT for detecting tissue structure and providing coordinates for the cutting process this system is capable of precise laser-surgery and online-therapy-control.