FIREFIGHTER’S VISIBILITY
FEATURES
SAFETY RESEARCH
A Closer Look at Contact Lenses
The authors of this article have conducted a first-hand, “real world” study of contact lenses in fire and smokefilled environments. Adhering to the Occupational Safety and Health Administration (OSHA) regulations requiring the use of self-contained breathing apparatus (SCBA) in hazardous atmospheres, the lenses were tested while wearing SCBA.
The OSHA recommendation prohibiting the use of contact lenses in contaminated atmospheres is being reevaluated, according to an OSHA official, and a questionnaire is being circulated to get input from firefighters who wear contact lenses in the field as to their comfort and the lenses’ performance inside SCBA. This survey, sponsored by OSHA, is being conducted by Lawrence Livermore National Laboratory.
To help gather this information on the benefits and drawbacks of contact lenses in firefighting, FIRE ENGINEERING has published a copy of the questionnaire on page 33. We ask that you take a few minutes to complete the survey and mail it to the Lawrence Livermore National Laboratory, R. A. da Roza, P.0. Box 808, L-386, Livermore, CA 94550. Thanks for your help.
The firefighting profession is the single most hazardous occupation in the United States today. It is also one of the most demanding occupations, requiring every sense to be alert to the dangers and the
Presupposing that the firefighter is in good physical condition and has no debilitating limitations, he must be able to hear the cry of a trapped victim or the call of a brother firefighter (see FIRE ENGINEERING, February 1984, “Don’t Turn a Deaf Ear to Hearing Losses”). He must be able to detect odors to assist in investigating and identifying the origin of the incident. He must be able to feel the fire’s intensity to know if he has gone in too far. And, above all, he must be able to see clearly, if only as far as the outside of his self-contained breathing apparatus (SCBA) mask, for his own safety as well as for the safety of others. Working at a fire in a smoke-filled atmosphere with an SCBA, good vision can mean the difference between successfully locating the fire or the victim and entrapment or possible death.
For firefighters needing corrective lenses, there are facepieces that allow for the wearing of eyeglasses inside the mask. However, these masks are specially designed and require special eyeglass frames. Other masks have an eyeglass frame insert in the facepiece itself.
However, the facepieces issued by many fire departments do not satisfy the vision needs of the firefighter who wears eyeglasses. This situation lends itself to the use of contact lenses.
Starting with the daily wear, hard plastic lens and evolving into the soft plastic/water extended wear lens, contact lenses have seen vast improvements in their size, shape, durability, and safety. Some of the advantages afforded contact lens wearers are clear vision in foul weather and unrestricted peripheral vision, something most difficult for the eyeglasses wearer.
The greatest vision difficulty encountered by any firefighter requiring corrective lenses is at night. For most of the firefighting force that works nights as well as days, the daily wear lens cannot serve their needs, and the benefits of extended wear lenses exceedingly outweigh the limited features of daily wear lenses.
In this study, three types of Federal Food and Drug Administration (FDA) approved, extended wear soft contact lenses having different chemical structures and water contents were tested for several months in both interior and exterior firefighting to determine comfort, protection, and, most important, overall vision. Worn with both positive pressure and demand-type SCBA, conditions ranged from the below freezing temperatures of winter fires to the extreme heat of fuel spill fires. Each set of lenses was worn on a continuous wear schedule of two weeks, after which the lenses were removed, cleaned by the chemical method of disinfection, and re-inserted for another 14-day period.
One major conclusion drawn from the testing was that all three lenses performed remarkably similar under firefighting conditions, rendering the wearer protection and, in all instances, better vision.
For the firefighter, the thickness of the lens and its water content might play an important role in the selection of the correct lenses. It was generally found during testing that the less water the lenses had, the easier and more stable they were to handle. This could be of value if the firefighter had to remove the lens on the fireground for whatever reason.
Contact lenses also offer a certain amount of eye protection. Because of the placement of this plastic/ water transparent lens on the surface of the cornea, it offers some safety from foreign matter coming in direct contact with the cornea. Should dirt or debris fall into the eye, the blinking of the eyelid will move the dirt to the corner of the eye where it can be removed, thus somewhat reducing the potential damage to the cornea.
Overall, comfortable wear was obtained with all three lenses during both night and day shifts. The only eye discomfort/irritation experienced with the contact lenses was after going from a cold atmosphere into a warm one. We are presently researching the effects that switching from one temperature extreme to another has on contact lenses.*
Comfort for the contact lens wearer is mostly subjective. The ability to even wear contact lenses is a matter that can only be answered after actual trial and error, wearing different lenses under the supervision of an eye doctor.
Nearly all firefighters have a tendency to remove their SCBAs prematurely. Some of the highest concentrations of fire gases are released during overhaul operations. Not only do these gases affect the respiratory system of the body, but they affect the eyes as well. Corneas need oxygen from the air. When exposed to smoke and fire gases, they can become infected or contract a conjunctivitis.
Through our testing, we’ve discovered that extended wear lenses can aid the firefighter’s vision in these smoke and gaseous conditions as well. Due to the increased tearing of the eyes as a result of a smoke environment, the eyes with contact lenses are not only lubricated, but actually increase in visual acuity. While other firefighters might have to leave a smoky atmosphere because of discomfort or pain, it was found that the wearing of contacts produced better vision and a certain lack of discomfort.
• It should be noted that contact lenses can melt at extremely high temperatures. However, the authors remarked that during firefighting operations in a superheated atmosphere with full SCBA, the temperature has no effect on the contact lenses. Despite inquiries to chemical companies, governmental agencies, and health facilities. FIRE ENGINEERING was unable to learn the melting temperature of soft contact lenses. However, both FIRE ENGINEERING and the authors of this article stress that SCBA must be worn during firefighting operations—whether or not contact lenses are used. See sidebar on the OSHA regulation regarding the use of corrective lenses and SCBA.
Regardless of the water content of the particular lenses tested, vision either improved or at least remained the same. This definitely is not a recommendation to remain in a hazardous atmosphere, but rather something to be considered when contemplating the use of contacts. Time and time again, the firefighter will need his eyes in a search and rescue operation. With the knowledge that contacts will protect his eyes and offer some degree of additional acuity, the firefighter may have an easier job.
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These extended wear contact lenses are not the final word in sight improvement for the firefighter. Even as this article goes to press, new lenses are being developed and sold on the market as a better aid to vision.
We tested these lenses in order to find any advantage possible for the firefighter in need of corrective lenses. If even one firefighter is aided, then all our jobs will be a little safer.
