Chris Miller, PHD
Vision plays a very important part of our lives. It provides about 75 percent of all sensory information transmitted to the brain. Thus, any factor that might affect vision quality such as environmental, biological or traumatic issues must be given immediate attention. Maintaining good vision is based upon regular visits to the eye doctor and use of proper protection whenever there is any chance for eye injury.
Chances for contamination
Hygienists and other dental team members have an increased chance for eye injury compared to many other professionals.
Working within a few inches of the patient`s mouth exposes dental team members to a shower of salivary aerosols and spatter droplets and projectiles of plaque, calculus, tooth structure, loosened restorative materials and pumice. Such materials can exit the mouth at high speeds causing body and environmental contamination and increasing the chances for traumatic eye injury.
The ultrasonic scaler, prophy angle and three-way syringe can cause great turbulence in the mouth generating contaminated aerosols (invisible fluid particles), spatter (larger fluid droplets) and injurious particulate matter. Although use of high-volume evacuation during prophys would greatly reduce contamination from this shower of oral materials, this technique is impossible to practice without a second pair of hands at chairside.
Potential eye injuries
Other chances for eye injury occur when handling chemicals of any type during patient care, operatory clean up, instrument processing, and developing X-rays. Liquid sterilants, disinfectants, surface cleaners, developer, fixer and detergents all deserve consideration as eye irritants from unsuspected splashes.
Direct contact eye injuries such as those caused by accidental encounters with a stray finger, thumb or instrument, operatory light handle or bracket table corner are fairly uncommon. However they can cause serious damage to unprotected eyes. Sharpening instruments with hand-held or stationary rotary devices and the use of rotary laboratory equipment also requires eye protection.
Most microbial contamination of the eye probably does not lead to harmful infections. However, it can be harmful if the contamination is heavy, if a highly virulent microbe is involved or if physical injury accompanies the microbial contamination that breeches the protective membranes of the eye.
One of the more serious harmful infections of the eye is a herpes virus infection that recurs like "fever blisters" causing more damage with each recurrence. A small number of people have herpes virus in their saliva in the absence of visual oral lesions and can serve as an unknown source of infection for unprotected eyes. Since hepatitis B was experimentally induced in chimpanzees through non-traumatic eye inoculation with infected serum, it appears that hepatitis B could develop in an unprotected person after initial contamination of the eye with virus-infected oral fluid.
Eye protection for patients also should be considered. Reports of patient eye injuries have included those involving impalement by an excavator; corneal abrasions from projectiles from an exploding anesthetic carpule and from a piece of acrylic denture tooth; and subconjunctival hemorrhage from contact with a dentist`s thumb.
Protective eyeglasses or face shields should be worn by all members of the dental team whenever there is a potential for eye contact with patients` oral fluids, projectiles or with chemicals used in the office. This potential exists during most intra-oral procedures and certainly for all of those involving the use of handpieces, ultrasonic scalers and the three-way syringe.
There may be good reason for the dental team to consider wearing protective eyewear for all chairside procedures. A mere cough by a patient can generate spatter and aerosols. This recently occurred, resulting in a dental student being sprayed in the face and eyes with bloody saliva. The student was even wearing glasses. However, they were small with prescription lenses the size of a quarter. Although, they looked good, they simply did not provide adequate protection during this unexpected incident.
Design of glasses
Protective glasses should be large enough to cover the eyes and should have side shields. Regular prescription glasses frequently offer minimum protection that can be enhanced with clip-on side shields. Face shields with curved sides to protect the sides of the eyes offer good protection from spatter, but they should be worn only with a mask.
Good eye and face protection by eyeglasses, goggles, and face shields are indicated when such products are designed, constructed, and tested in accordance with the American National Standards Institute`s (ANSI) Practice for Occupational and Educational Eye and Face Protection.
Decontaminating protective eyewear can be accomplished by wearing gloves and washing the eyewear with the antimicrobial handwashing agent used in the office. This is followed by rinsing with tap water and drying. Avoid splashing while cleaning.
If eyewear is decontaminated by washing and treatment with a disinfectant such as an iodophor, be sure to rinse away any residual chemicals to reduce chances for subsequent skin or eye irritation. Some eyewear may be adversely affected by chemicals in handwashing agents or disinfectants.
References are available upon request from the author.
Chris Miller is director of Infection Control Research and Services and professor of oral biology at Indiana University.