Wavefront sensorless adaptive optics for optical coherence tomography guided femtosecond laser surgery in the posterior eye

摘要

Surgery with fs-laser in the posterior part of the eye could be useful for separation of tractional epiretinalmembrane and vitreous oaters treatment. However, focus degradation occurs near the retina due to inducedaberrations by cornea and lens. To overcome this issue, adaptive optics with wavefront sensor and wavefrontmodulator can be utilized. We demonstrate an alternative concept for image guided femto second laser (fs-laser)surgery in the posterior eye with wavefront sensorless adaptive optics (WFSLAO). Our laboratory setup consistsof an 800nm fs-laser and a superluminescent diode (SLD) with 897:2nm central wavelength. The SLD is used foroptical coherence tomography (OCT) whereby the light for the OCT sample arm and the fs-laser share the sameoptical path which contains a deformable mirror, scanner and focusing optics. Energy calibrated photodiodesare used to measure the threshold energy for a laser induced optical breakdown inside a water filled chamberthat acts as simple eye model. OCT image based metrics were used to determine a set of Zernike polynomialsthat describe a near optimal deformable mirror state. Such a mirror state improved OCT resolution and atthe same time lowered the required fs-laser energy for a laser induced optical breakdown inside the eye modelsubstantially.