Spatial Beam Shaping for Femtosecond Laser in Vitreo-Retinal Surgery

In ophthalmic surgery, femtosecond laser pulses provide a high precision tool for tissue dissection in the anterior part of the eye with little peripheral implications. However, for an application in the posterior part the precision is diminished by the aberrations of the eye which also cause higher pulse energy required for photodisruption. In order to increase the precision and decrease the pulse energy for vitreo-retinal surgery an adaptive optics system was designed for spatial beam shaping of femtosecond laser pulses. A Hartmann-Shack-Sensor was used for aberration measurement and a deformable mirror for aberration correction. The influence of an adaptive optics aberration correction on the resulting wave front and incision process was investigated in an eye model. The adaptive optics system designed for the requirements of vitreoretinal surgery provides a wave front correction with diffraction limited precision. The spatial confinement as a consequence of the corrected wave front decreases the pulse energy for the incision process in the model eye. As less energy is required for the incision process adaptive optics in a femtosecond laser scalpel potentially allow for tissue dissection with reduced peripheral damage. This offers new possibilities for non-invasive high precision surgery in the posterior eye segment and the treatment of vitreal and retinal pathologies.