Mrochen M, Petersen H, Wüllner C, Seiler T
Augenklinik im Universitätsklinikum Carl Gustav Carus der TU-Dresden.
Klin Monbl Augenheilkd. 1998 Jan;212(1):50-4. doi: 10.1055/s-2008-1034831.
Vitrectomy performed by conventional guillotine devices includes the risk of mechanical damage to retina as well as other ocular structures. The present study aims to investigate the efficacy of the Er:YAG laser for vitreous liquefaction.
Vitreous liquefaction by means of Er:YAG laser pulses was performed using a special handpiece. The output of an Er:YAG laser operating at 2.94 microns was coupled into a ZrF optical fibre (length 2 m) which ended inside a cavity located at the quartz tip (diameter 320 microns) of the handpiece where tissue ablation took place. The viscosity of the liquefied vitreous was determined by rotation viscosimetry and compared to liquefied vitreous obtained by mechanical vitrectomy. In addition, the aspiration flow (ml/min) was correlated to the repetition/cutting rate of the laser and the cutter. The temperature rise at the handpiece was recorded with a micro thermocouple.
The cutting threshold was determined to 5 mJ +/- 3 mJ at a pulse duration of 200 microseconds. The viscosity of the vitreous liquefied with the Er:YAG laser was 31 +/- 10 mPa s which is similar to the results of mechanical vitrectomy (42 +/- 19 mPa s) but significant less than that of normal vitreous (880 +/- 280 mPa s). The aspiration of the laser handpiece in dependence to the repetition rate increases linear up to 2.6 ml/min at 30 Hz. The temperature increase at the handpiece was < 1 K under vitrectomy conditions (aspiration and irrigation) with an averaged laser power of 0.3 W (10 mJ at 30 Hz).
The decreased vacuum forces used by the laser vitrectomy system may result in less mechanical stress to the retina as well as intravitreal structures which may be attached to it. An Er:YAG laser vitrectomy system may offer the potential of fewer complications during vitrectomy.
使用传统的断头台式设备进行玻璃体切割术存在机械损伤视网膜以及其他眼部结构的风险。本研究旨在探讨铒激光对玻璃体液化的疗效。
使用特殊手持件通过铒激光脉冲进行玻璃体液化。波长为2.94微米的铒激光输出耦合到一根ZrF光纤（长度2米）中，该光纤末端位于手持件的石英尖端（直径320微米）内的一个腔中，组织消融在此处发生。通过旋转粘度测定法测定液化玻璃体的粘度，并与通过机械玻璃体切割术获得的液化玻璃体进行比较。此外，抽吸流量（毫升/分钟）与激光和切割器的重复/切割速率相关。用微型热电偶记录手持件处的温度升高。
在200微秒的脉冲持续时间下，切割阈值确定为5毫焦±3毫焦。用铒激光液化的玻璃体粘度为31±10毫帕·秒，这与机械玻璃体切割术的结果（42±19毫帕·秒）相似，但明显低于正常玻璃体（880±280毫帕·秒）。激光手持件的抽吸量随重复频率增加而线性增加，在30赫兹时可达2.6毫升/分钟。在玻璃体切割术条件（抽吸和冲洗）下，平均激光功率为0.3瓦（30赫兹时为10毫焦）时，手持件处的温度升高<1开尔文。
激光玻璃体切割系统使用的真空力降低，可能会减少对视网膜以及可能附着在其上的玻璃体内结构的机械应力。铒激光玻璃体切割系统可能在玻璃体切割术中提供并发症更少的潜力。
