YAG:Er laser device for microsurgery treatment of a human lens cataract

We have designed a laser complex which is a combination of a YAG:Er laser operating in the free-running mode, a radiation delivery system based on a chalcogenide fiber with uniquely high damage threshold, and a diagnostic optical coherent tomography (OCT) device for in situ monitoring of surface layers of the tissue under treatment. A flexible chalcogenide glass multimode fiber operates with pulse energy 150 mJ at a repetition rate of 3 Hz. Neither degradation nor laser damage were observed after transmission of 10 4 laser pulses through the fiber delivery instrument. This complex was employed to study the effect of YAG:Er laser radiation on a cataract-suffered human lens. The laser ablation process has been monitored by OCT. During the lens treatment the image of ablation crater and inner layers with a scanning depth of several millimeters and spatial resolution of 15 micrometers was available. The kinetics of pulse-to-pulse ablation crater growth a well as of the adjacent thermally damaged zone formation were investigated.