Myers J S, Trevisani M G, Imami N, Herndon L W, Wolbarsht M L, Allingham R R, Straub K D, Shields M B
Duke University Eye Center, Duke University, Durham, NC 27710, USA.
Arch Ophthalmol. 1998 Apr;116(4):488-91. doi: 10.1001/archopht.116.4.488.
To measure scattered laser energy reaching the posterior pole during transscleral cyclophotocoagulation.
Transscleral cyclophotocoagulation was performed on 4 cadaver eyes with Nd:YAG noncontact, Nd:YAG contact, and diode contact lasers. Energy was measured with a photodiode through a 7-mm trephined hole in the posterior pole. Average percentage power, average power, and average energy transmission were calculated. American Conference of Governmental Industrial Hygienists (ACGIH) guidelines were used to calculate allowable energy exposures for each laser.
All 3 lasers transmitted 3% to 5% of the power to the posterior pole. The average energy transmission was 240 to 260 mJ for all lasers. The contact lasers had an average power transmission of 120 mW. The noncontact Nd:YAG laser, with shorter pulse duration, had an average power transmission of 13,000 mW, significantly greater than that of the other lasers. The ACGIH guidelines for allowable energy exposures were 93 mJ for the noncontact Nd:YAG laser, 1300 mJ for the contact Nd:YAG laser, and 440 mJ for the contact diode laser.
Three percent to 5% of laser power delivered during cyclophotocoagulation reaches the posterior pole. Exposure energies may approach or exceed ACGIH guidelines. The clinical significance of these findings remains to be shown.
测量经巩膜睫状体光凝术期间到达后极部的散射激光能量。
使用钕:钇铝石榴石非接触式、钕:钇铝石榴石接触式和二极管接触式激光对4只尸体眼进行经巩膜睫状体光凝术。通过后极部一个7毫米的环钻孔，用光电二极管测量能量。计算平均功率百分比、平均功率和平均能量传输率。采用美国政府工业卫生学家会议（ACGIH）指南计算每种激光的允许能量暴露量。
所有3种激光均将3%至5%的功率传输至后极部。所有激光的平均能量传输为240至260毫焦。接触式激光的平均功率传输为120毫瓦。脉冲持续时间较短的非接触式钕:钇铝石榴石激光的平均功率传输为13000毫瓦，显著高于其他激光。ACGIH指南规定的非接触式钕:钇铝石榴石激光允许能量暴露量为93毫焦，接触式钕:钇铝石榴石激光为1300毫焦，接触式二极管激光为440毫焦。
睫状体光凝术期间传输的激光功率有3%至5%到达后极部。暴露能量可能接近或超过ACGIH指南规定的值。这些发现的临床意义尚待阐明。
