Eye Safety of Laser and Light-Based Devices

24.1 I ntroduction

Ocular safety of both laser and intense-pulse light (IPL) devices is always important to protect both the user and patient from potential hazards. Questions also sometimes arise regarding the eye safety of the much lower power Light Emitting Diode (LED) devices. Safety has always been important for any laser application in surgical procedure, and sev­eral issues dominate. Two key issues arise: (1) wearing eye protectors by the clinical staff and (2) protecting the eyes of the patient. No one denies that lasers can pose a serious haz­ard to the eye, but other light-based systems may also pose similar hazards, particularly for the patient. For periorbital surgery in particular, the type of protector for the patient’s eyes can vary with the wavelength and the type of laser. Since the penetration of laser light through the lid and adjacent tissues vary, the criticality of the eye protector has not been fully appreciated, and the decision to use some types of eye protectors in some procedures has been frequently questioned. Fortunately, eye injuries are becoming much less likely because of the development of more contact applicators. Other ancillary safety issues include the need to properly deal with the plume of vaporized tissue during ablative proce­dures and controlling potential fire hazards. The choice of control measures to minimize the very serious risk from chronic breathing of vaporized tissue also requires judgment.

With the increasing variety of lasers and the number of wavelengths now available, safe laser use has become a more complex issue [1]. The extent of potentially hazardous reflec­tions, the type of eye protection, and the ancillary hazards can vary considerably with the type of laser used and the procedure. However, in all cases, the laser operator (the clinical user) and the staff must be concerned with both the protection of the patient, and the protec­tion of the persons in the vicinity of the procedure. Patient safety is assured by limiting needless exposure to adjacent tissues (by choice of wavelength and to a large extent by tech­nique), using noncombustible materials adjacent to the beam, and by properly protecting the patient’s eyes. Safety of the operator and assistants requires concern for both system-safety design and the means to limit potentially hazardous reflections. For ablative procedures, the environmental hazards from the smoke produced by vaporizing tissue must be minimized by local exhaust ventilation or fume extractors. The pathogenicity and chemical toxicity of vaporized tissue has been the subject of a number of investigations, as discussed later. Safety standards for medical laser applications have been issued, which consider all these potential hazards and their control measures [1-10]. The current consensus standard in the United States, that is, the American National Standard Z136.3-2005, Safe Use of Lasers in Health Care Facilities [4], and similar user guidelines have been crafted to provide a realistic and balanced approach to clinical laser safety, hopefully without needless control measures. Realistic safety procedures can be achieved only if the entire community of laser users par­ticipates in the development of consensus standards and codes of practice.

The one hazard that is truly unique to the laser, and that requires special attention results from the laser beam itself—the optical radiation hazard. Unlike other light sources, the laser beam may be collimated and directed over some distance; hence the area of potential hazard may not be limited to the immediate surgical site. Unwarranted fears often accom­pany the introduction of lasers into the clinical environment. Therefore, proper apprecia­tion of the real laser-beam hazard is necessary for each member of the professional staff so that realistic safety precautions are followed [10-18] . In most countries, occupational safety and health regulations emphasize the critical importance of informing and educating the worker on workplace risks, and this is clearly important regarding laser use [19].

Laser hazards depend on the laser in use, the environment, and the personnel involved with the laser operation (the operator, ancillary personnel, and the patient). The laser hazard is roughly defined by the hazard classification [1-4], while the other factors must be analyzed in each situation. A basic understanding of laser biological effects and hazards is necessary to assess each laser hazard in the operating room intelligently. Once the hazards are understood, the safety measures become obvious.

Updated: October 7, 2015 — 6:21 pm