According to the Contact Lens Institute, today there are 26 million contact lens wearers, and this number is expected to rise. In determining policies that involve corrective eyewear and eye protection, employers must face the facts: An increasing number of employees are likely to wear contact lenses and employees have the right to choose their own eye accommodations.
In making these decisions, chemical health and safety professionals, lab supervisors, and management must consider both the risks and benefits of contact lenses, and they must differentiate objectively between perceived and actual risks. In this article, I summarize the current status of the use of contact lenses in the chemical workplace.
Have policies concerning contact lenses in chemical-use areas changed significantly since I last addressed this issue (1)? A search of this topic in the Safety archives netted 146 hits from July 7, 1991, through Sept. 26, 1996. All these messages show that there still is a lot of confusion, variability in policies, and arbitrary enforcement.
To begin this update, I sent a query to the Safety listserv asking for current policies on the wearing of contact lenses in chemical-use areas. Although the responses varied, the following comments are representative:
After summarizing the responses, I compared them with a similar survey in June 1994 (1). In academia, restrictions on contact lenses are being relaxed as long as the proper eye protection is used. In 1994, 21 institutions allowed contact lenses and 16 banned them. In 1997, 20 institutions responded that they allow contact lenses; the number banning their use was 6. In industry in 1997, I found that 15 companies allowed the use of contact lenses and 11 banned them (corresponding figures for 1994 are not available).
PPE Standard. In recent years, the hazard assessment feature of this OSHA standard (2) has had a significant effect. Employers are required to assess the workplace to determine if hazards that require the use of PPE are present or likely to be present. If hazards or the likelihood of hazards are found, employers must select and have affected employees use properly fitted PPE suitable for protection from existing hazards. It is imperative to note that the standard emphasizes that PPE should not be used as a substitute for engineering, work practice, and/or administrative controls. What this means is that hoods and ventilation should be available for hazardous work, so the risk of any contact with chemicals is minimal. People should not have to work in contaminated areas.
Eye and face protection is covered under 29 CFR 1910.133 and must be in accordance with ANSI Z87.1 (USA Standard Practice for Occupational and Educational Eye and Face Protection). Because OSHA has codified the voluntary ANSI Z87.1 consensus standard, compliance with ANSI Z87.1 is mandatory. In reference to contact lenses, Z87.1 states only that, "Wearers of contact lenses shall also be required to wear appropriate covering eye and face protection devices in a hazardous environment. It should be recognized that dusty and/or chemical environments may represent an additional hazard to contact lens wearers." The ANSI guidelines are in the process of revision; the target date for release of the revised document is October 1997. No revision to the contact lens statement is anticipated.
Respirator standard. Another impact came from OSHA when it turned its back on its ban on contact lens use with respirators (3). After an OSHA-funded research project at Lawrence Livermore National Laboratories assessed the hazards associated with the wearing of contact lenses with full-facepiece respirators by firefighters, OSHA in 1994 adopted the policy that "violations of paragraph (e) (5) (ii) involving the use of soft (hydrophilic) contact lenses with any type of respirator shall be characterized as de minimis if it has no direct or immediate relationship to employee safety or health. Citations are not issued for de minimis violations, and there is no monetary penalty or requirement for abatement" (3).
Another Proposed Rules publication included the statement, "OSHA believes the Lawrence Livermore contact lens study of fire fighters supports removing the prohibition on the use of contact lenses with respirators. No evidence shows that wearing contact lenses with respirators increases safety hazards. Therefore, OSHA is proposing to remove the prohibition in the current standard on the use of contact lenses with respirators." (Note that it is easier to make regulations than to remove them.)
ADA. One must also consider the Americans with Disabilities Act of 1990, which requires that workers who can perform the essential functions of the position with or without accommodation (job or facilities) without substantial risk of threat to themselves or others should not be restricted in performing their duties in a given position.
Because of this ruling, in the case of contact lenses, the American College of Ophthalmology (ACO) and the American College of Occupational and Environmental Medicine (ACOEM) have reviewed former policies that banned contact lenses in the workplace and now agree that, under the ADA, individuals who wear contact lenses should not be disqualified from their work unless it can be proved that they pose a direct threat to the health or safety of themselves or others in the workplace (4).
There have been times when workers who wear contact lenses, either for cosmetic or medical reasons, have been disqualified from certain positions. Dr. Bernard Blais, in a Letter to the Editor in the Journal of Occupational Medicine (5), states that, "in fact, it could be discriminatory if the employer prevented an employee from wearing contact lenses on an industrial site when the contacts were a means of accommodation to performing the essential functions of the position." It is the recommendation of ACOEM and ACO that medical personnel should determine, on an individual basis, the advisability of wearing lenses in the industrial work environment. Individuals should be instructed in the principles of contact lens wear and the symptoms of problems, and they should be urged to seek immediate help if an injury occurs.
Contact lenses can fuse to the eyeball. The infamous "Baltimore" incident (1) even though repudiated widely and published as false and incredible, still has believers. Allegedly a worker was blinded because an electric arc caused his contact lens to fuse to his eyeball. In one response I received from a large prestigious university, it was noted that contact lenses were banned and that the students didn't argue after being told that "contact lenses could fuse to their eyes." Rumors have a tendency to be cited later as facts. According to Cullen (6), the claims that heat from electric arcs caused fusion of contact lenses to corneas are not physically, anatomically, or physiologically possible.
Contact lenses can hold foreign materials against the cornea. There is a perception that chemicals can be trapped behind hard contact lenses or may be absorbed, concentrated, and released by hydrogel contact lenses onto an already compromised cornea. And by holding the chemical against the eye, the contact lenses cause worse than normal injury. It also has been suggested that the presence of a lens on the eye would prevent adequate irrigation.
The basis for this appears to be an undocumented case in 1969, but cited two years later by Novak and Saul (7), in which a process engineer was conducting an experiment wearing contact lenses and safety goggles. Some 50% caustic solution was splashed into his eyes and face. Emergency treatment was reported to have washed the chemical from his face and partially from his eyes. It was claimed that some of the chemical was trapped beneath the contact lens, causing severe burns of the eye before the contact lenses could be removed. It was not stated whether the goggles worn were baffled to prevent splash entry. The possibility of such an occurrence while wearing protective goggles has been deemed highly questionable. Undocumented cases such as this, however, form the basis for claims that contact lenses have no place in the chemical laboratory.
Contact lenses present a particular hazard because they can absorb and retain chemical vapors. The greatest concern with contact lenses is the fact that gases, vapors, fumes, and smoke can seep behind inappropriate protective devices and directly affect the eye. It has been noted, however, that many hydrogel contact lens wearers claim that they are able to peel onions without the usual excessive tearing, thus demonstrating protection by the lenses against the tearing action of the allyl disulfides present in onions.
Also reported is protection against tear gases (e.g., o-chlorobenzylidene malononitrile), which are insoluble in water, as determined in a study by Aalphen and co-workers (8). They reported that individuals wearing contact lenses and exposed to tear gas kept their eyes open more easily, recovered faster, and suffered minimal damage compared with those not wearing contacts. They concluded that the idea that soft contacts absorbed airborne chemicals during wear was not supported by their study.
In a more recent study in 1995, LaMotte and colleagues (9) examined the absorption of ammonia vapors in high water content hydrogel lenses in a 0.9% saline solution. They found that the impregnated contact lens released ammonia very rapidly when it was placed in a solution simulating tears. The lens did not act like a "sponge" that could slowly release an absorbed compound over an extended period, but instead lost ammonia within seconds of immersion.
In 1992, researchers in a study at the Department of Ophthalmology at the University of Nebraska Medical Center in Omaha (10) tested absorption of acetone, diethyl ether, trichloroethylene, and toluene using normal saline solution; they concluded that contact lenses worn in environments containing volatile organic solvents may decrease the exposure of the eye to these compounds.
This finding corroborates a 1982 study in which Nilsson and Andersson (11) concluded that the absorption of trichloroethyene and xylene vapors by hydrogel contact lenses is not as dangerous as previously thought and that the "vacuum cleaner" effect of the lenses would result in a lower concentration at the corneal surface than if the eye were exposed directly.
Isopropyl and ethyl alcohol vapors are contraindicated with contact lenses. This caution is extrapolated from the results of an Italian study in 1985 (12) in which researchers found that these compounds could pass through or bind to the contact lens surface and be released later into the tear film. The study was performed in situ, but it was suggested that workers should take precautions when wearing hydro- philic contact lenses in these environments. Experiments with different chemicals are referenced in my prior paper (1).
Contact lenses exacerbate potential damage from corrosive chemical splashes. Concentrated acids and bases can cause severe and permanent destruction to the eye if they are not removed immediately. Alkalies can cause greater damage than acids because they can penetrate deeper. In one study, hydrogel lenses provided no protection against 20 or 40% NaOH, but the lenses did not worsen the condition (11).
Defense mechanisms of the eye include blepharospasm (lid spasm) and lacrimation (tearing), which limit access to the eye and dilute the concentration of the chemical, respectively. Lid spasm causes the lens to tighten against the cornea, thereby effectively sealing off the area under the lid.
The following real-life incidents reported on the Safety listserv illustrate some of these effects:
Blais (14) points out there is a new irrigation system called the "eye irrigator," which was first demonstrated at the American Occupational Health Conference in May 1996. Instead of having to pry open the eye, the individual rendering assistance inserts an irrigation loop under the upper eyelid. An anesthetic may or may not be needed. In Hough's article (15), Blais advises that contact lenses should not be taken out; rather, they should be allowed to flow out with the irrigating solution. He notes, "In some cases, the contact lens protects the eye against further chemical damage."
In 1980, the American Academy of Ophthalmology stated that the wearing of contact lenses to increase visual acuity should be encouraged in combination with proper eye protection, except where there is the likelihood of injury from intense heat, massive chemical splash, highly particulate atmosphere, or where federal regulations prohibit such use.
The National Safety Council has published guidance that recommends that contact lenses be permitted in all occupational settings, unless specifically prohibited for operational reasons.
The Canadian Centre for Occupational Health and Safety, back in 1985, issued a statement that, "When performing functions requiring eye protection and suitably protected, the contact lens wearer may be given equal consideration to that given any person with normal sight." That statement has not been changed.
Tod W. Turriff, director of programs at Prevent Blindness American, claims that eye protection is the most important factor to consider. Contact lens use should be made on a case-by-case basis in situations where chemicals are involved.
Chemical Safety Associates, a consulting firm, advises its clients who want to allow their employees to wear contacts to do so, but to implement an effective eye protection program through the use of safety glasses, splash goggles, and engineering controls.
The American Chemical Society's Committee on Chemical Safety states in Safety in Academic Chemistry Laboratories (17) that, "Contact lenses should not be worn in the chemistry laboratory except for therapeutic reasons....In the event of a chemical splash into an eye, capillary action tends to hold the offending liquid under the contact lens and against the surface of the cornea. In that event, the removal of the contact lens to achieve immediate irrigation is made nearly impossible by involuntary spasm of the eyelid....Gases and vapors can concentrate under the lenses and cause permanent eye damage. Contact lenses can also trap particulate foreign matter in the eye and thereby produce abrasion of the cornea. For these reasons, only contact lenses worn for therapeutic reasons can be permitted in the laboratory."
Because evidence has refuted some of these statements, the Committee on Chemical Safety considered the matter in a recent meeting; it is in the process of evaluating the text. For example, one has to ask what is meant by therapeutic reasons? Certainly, conditions such as keratoconus or aphakia, but what about correction of refractive errors, which some describe as cosmetic? Isn't it interesting that insurance companies classify contact lenses used to correct refraction as a fashion device (i.e., "cosmetic use"), while reimbursing the cost of designer spectacles.
One respondent commented, "My health care provider considers contact lenses cosmetic. With the current cost of lightweight, top-of-the-line frames and lenses running in excess of $500, the $100--300 I paid for high oxygen transfer, tinted hard lenses every 3--4 years looks like a real bargain!"
Other regulations prohibit contact lenses when working with 1,2-dibromo-3- chloropropane (1910.1044), acrylonitrile (1910.1045), ethylene oxide (1910.1047), and methylenedianiline (1910.1050). In the Laboratory Standard (1910.1450), there is a statement "Avoid use of contact lenses in the laboratory, unless necessary; if they are used, inform the supervisor so special precautions can be taken."
In assessing any risks, it is helpful to compare the advantages and disadvantages (see the box on p. 35). Clearly there are more advantages in the use of contact lenses.
Employers, CHOs, and supervisors should take a look at their contact lens policies and, based on current knowledge, reevaluate them. If they have no policies, it's time to establish some. Elements should include
More research needs to done about the effects of chemicals on various contact lens material and specific workplace environments, but enough information is presently available to establish flexible policies in the workplace and to allow workers to benefit from the many advantages of contact lenses.
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