Denial A, Hanley M
New England College of Optometry, Boston, Massachusetts, USA.
Optometry. 2001 Jan;72(1):45-51.
The purpose of this study was to calculate the retinal irradiance and maximum permissible exposure time (MPE) using high plus fundus biomicroscopy lenses.
Four Volk handheld condensing lenses (+78 D, +90 D, Superfield NC, and Super 66) were tested with biomicroscopes from three manufacturers (Nikon, Topcon, and Zeiss) on both high and medium illumination. Using the conservation of radiance theorem, the retinal irradiance was calculated and. with guidelines from the American National Standard Institute (ANSI). the maximum permissible exposure time was determined.
The range of MPE time across all lenses and biomicroscopes was from 23 seconds to 74 seconds on high illumination setting. The average MPE times were: for the +78 D, 36 seconds; the Superfield NC, 57 seconds; the Super 66, 32 seconds; and the +90 D, 52 seconds.
Retinal irradiances and safe exposure times are useful guidelines in both the clinical and academic setting. Fundus biomicroscopy with non-contact high plus condensing lenses produced calculated retinal irradiances and MPE times similar to those of other commonly used ophthalmic equipment. Awareness of the maximum permissible exposure time increases the safety of this valuable technique.
本研究的目的是使用高屈光度眼底生物显微镜镜片计算视网膜辐照度和最大允许暴露时间（MPE）。
使用来自三个制造商（尼康、拓普康和蔡司）的生物显微镜，在高、中两种光照条件下，对四种沃克手持聚光镜片（+78D、+90D、Superfield NC和Super 66）进行测试。利用辐射守恒定理计算视网膜辐照度，并根据美国国家标准学会（ANSI）的指导方针确定最大允许暴露时间。
在高光照设置下，所有镜片和生物显微镜的MPE时间范围为23秒至74秒。平均MPE时间分别为：+78D镜片36秒；Superfield NC镜片57秒；Super 66镜片32秒；+90D镜片52秒。
视网膜辐照度和安全暴露时间在临床和学术环境中都是有用的指导原则。使用非接触式高屈光度聚光镜片的眼底生物显微镜产生的计算视网膜辐照度和MPE时间与其他常用眼科设备相似。了解最大允许暴露时间可提高这项重要技术的安全性。
