Disclaimer
Mention of any company or product does not
constitute endorsement by the National Institute for Occupational Safety
and Health (NIOSH). In addition, citations to Web sites external to
NIOSH do not constitute NIOSH endorsement of the sponsoring organizations
or their programs or products. Furthermore, NIOSH is not responsible
for the content of these Web sites.
Ordering Information
To receive documents or other information about
occupational safety and health topics, contact NIOSH at:
NIOSH—Publications Dissemination
4676 Columbia Parkway
Cincinnati, OH 45226–1998
Telephone: 1–800–35–NIOSH (1–800–356–4674)
Fax: 513–533–8573
E-mail: pubstaft@cdc.gov
or visit the NIOSH Web site at www.cdc.gov/niosh
Foreword
The purpose of the Occupational Safety and Health Act of 1970 (Public
Law 91–596) is to assure safe and healthful working conditions
for every working person and to preserve our human resources. In this
Act, the National Institute for Occupational Safety and Health (NIOSH)
is charged with recommending occupational safety and health standards
and describing exposures that are safe for various periods of employment,
including (but not limited to) the exposures at which no worker will
suffer diminished health, functional capacity, or life expectancy as
a result of his or her work experience.
Current Intelligence Bulletins
(CIBs) are issued by NIOSH to disseminate new scientific information
about occupational hazards. A CIB may draw attention to a formerly
unrecognized hazard, report new data on a known hazard, or disseminate
information about hazard control. CIBs are distributed to representatives
of academia, industry, organized labor, public health agencies, and public
interest groups as well as to Federal agencies responsible for ensuring
the safety and health of workers.
This CIB reviews what is known about
contact lens wear while working with chemicals and provides guidelines
for their use in a chemical environment to help employers safely implement
a contact lens use policy.
|
John Howard, M.D.
Director, National Institute for
Occupational Safety and Health
Centers for Disease Control and Prevention |
Abstract
Since the 1978 Standards Completion Program, the National Institute
for Occupational Safety and Health (NIOSH) has recommended that workers
not wear contact lenses during work with chemicals that present an eye
irritation or injury hazard. Recently, several professional groups have
issued guidelines removing restrictions in the industrial environment.
NIOSH has reviewed these guidelines, company policies on contact lens
use and injury incidents, and the limited literature on contact lens
use in a chemical environment. Injury data are lacking to indicate that
contact lens wear should be restricted during work with hazardous chemicals,
and thus NIOSH recommends that contact lens wear be permitted provided
that the safety guidelines presented in this Current Intelligence Bulletin
(CIB) are followed.
Acknowledgments
The authors would like to thank the following individuals for their
assistance in reviewing this document:
Dr. Bernard Blais
American College of Occupational and Environmental Medicine
Dr. Anthony Cullen
American Optometric Association
Dr. Diane Schmidt
American Chemical Society
Ms. Eileen Segal
American Chemical Society
Mr. John Shoemaker
Prevent Blindness America
Mr. Bill Kojola
AFL–CIO
Ms. Ann Brockhaus
Organization Resource Counselors
Dr. Robert Ford
Eastman Kodak Company
Ms. Michelle Castleberry
American Association of Occupational Health Nurses
Dr. Caroline Freeman
Occupational Safety and Health Administration
Editorial review and production assistance were provided by Anne C.
Hamilton and Vanessa L. Becks.
Contact Lens Use in a Chemical Environment
Background
Since 1978, the National Institute for Occupational Safety and Health
(NIOSH) has recommended that workers not wear contact lenses during work
with chemicals that present an eye irritation or injury hazard [NIOSH
2004]. This policy was recommended by the 1978 Standards Completion Program
and is based on the “best professional opinion of the
committee membership based on literature data ” [NIOSH
1978]. The policy was also consistent at that time with general industry
practice, Occupational Safety and Health Administration (OSHA) regulations,
and recommendations of professional groups such as the American Chemical
Society.
Current Practice
Recently, a number of groups have issued new guidelines that remove
most previous restrictions for wearing contact lenses in the industrial
environment. These groups include the American Optometric Association,
the American College of Occupational and Environmental Medicine, the
American Academy of Ophthalmology, the American Chemical Society, and
Prevent Blindness America. NIOSH has reviewed these new guidelines as
well as the limited literature on the use of contact lenses in a chemical
environment and the potential absorption and adsorption of chemicals
by contact lenses. In addition, NIOSH has reviewed company policies on
contact lens use and injuries involving contact lenses among a small
number of chemical manufacturing firms. Some of these companies continue
to restrict contact lens wear in their work settings, but others have
relaxed their restrictions.
Experimental Studies
In general, injury data are lacking to clearly indicate that contact
lens wear should be restricted during work with hazardous chemicals;
however, appropriate eye protection is always necessary. Only limited
research has been conducted on the hazards of wearing contact lenses
when working with specific chemicals. Several laboratory studies have
focused on absorption and adsorption of acids, bases, and other solvents
by contact lenses [LaMotte et al. 1995; Hejkal et al. 1992; Nilsson and
Andersson 1982]. In these experimental studies, various lens materials
were exposed to chemicals for extended periods using either vials or
animals. The results suggest that contact lens uptake and release of
chemicals to eye tissue is not likely to be a significant issue for workers
wearing contact lenses. However, one similar laboratory in vitro study
indicates that isopropyl and ethyl alcohol may pose risks to exposed
workers wearing contact lenses [Cerulli et al. 1985].
In all of these studies, researchers examined the resistance of contact
lenses to chemical exposures under test conditions. They did not examine
actual chemical exposures in workers and did not examine the use of appropriate
eye protection simultaneously with contact lens use.
Wearing contact lenses under some circumstances provides workers with
a greater choice of eye and face protection (such as goggles or full-facepiece
respirators without prescription inserts) as well as better visual acuity.
However, the risk is unknown for contact lens wearers compared with nonwearers
working with chemicals listed in the NIOSH Pocket Guide to Chemical
Hazards [NIOSH 2004]. Currently, OSHA recommends against contact
lens use when working with acrylonitrile, methylene chloride, 1,2 dibromo-3-chloropropane,
ethylene oxide, and methylene dianiline. These recommendations are presumably
based on best professional judgment, as no specific bases are provided
in the preambles to these standards.
Recommendations
NIOSH recommends that workers be permitted to wear contact lenses when
handling hazardous chemicals provided that the safety guidelines listed
here are followed and that contact lenses are not banned by regulation
or contraindicated by medical or industrial hygiene recommendations.
However, contact lenses are not eye protective devices, and wearing them
does not reduce the requirement for eye and face protection. The following
guidelines for contact lens use in a chemical environment will help occupational
safety and health professionals and employers safely implement the contact
lens use policy:
- Conduct an eye injury hazard evaluation in the workplace
that includes an assessment of the following:
- Chemical exposures (as required by OSHA’s personal
protective equipment standard [29 CFR * 1910.132])
- Contact lens wear
- Appropriate eye and face protection for contact lens wearers
The eye injury hazard evaluation should be conducted by a competent,
qualified person such as a certified industrial hygienist, a certified
safety professional, or a toxicologist.
Information from the hazard
evaluation should be provided to the examining occupational health
nurse or occupational medicine physician.
The chemical exposure assessment
for all workers should include, at a minimum, an evaluation of the
properties of the chemicals in use—including
concentration, permissible exposure limits, known eye irritant/injury
properties, form of chemical (powder, liquid, or vapor), and possible
routes of exposure. The assessment for contact lens wearers should
include a review of the available information about lens absorption
and adsorption for the class of chemicals in use and an account of
the injury experience for the employer or industry, if known.
- Provide suitable eye and face protection for all workers
exposed to eye injury hazards, regardless of contact lens wear. Wearing
contact lenses does not appear to require enhanced eye and face
protection. For chemical vapor, liquid, or caustic dust hazards,
the minimum protection consists of well-fitting nonvented or indirectly
vented goggles or full-facepiece respirators. Close-fitting safety
glasses with side protection provide limited chemical protection
but do not prevent chemicals from bypassing the protection. Workers
should wear face shields over other eye protection when needed
for additional face protection; but they should not wear face shields
instead of goggles or safety glasses—regardless
of contact lens wear.
- Establish a written policy documenting general safety
requirements for wearing contact lenses, including the eye and face
protection required and any contact lens wear restrictions by work
location or task. In
addition to providing the general training required by the OSHA
personal protective equipment standard [29 CFR 1910.132], provide
training in employer policies on contact lens use, chemical exposures
that may affect contact lens wearers, and first aid for contact
lens wearers with a chemical exposure.
- Comply with current OSHA regulations on contact lens wear
and eye and face protection.
- Notify workers and visitors about any defined areas where
contact lenses are restricted.
- Identify to supervisors all contact lens wearers working
in chemical environments to ensure that the proper hazard assessment
is completed and the proper eye protection and first aid equipment
are available.
- Train medical and first aid personnel in the removal of
contact lenses and have the appropriate equipment available.
- In the event of a chemical exposure, begin eye irrigation
immediately and remove contact lenses as soon as practical. Do
not delay irrigation while waiting for contact lens removal.
- Instruct workers who wear contact lenses to remove the
lenses at the first signs of eye redness or irritation. Contact
lenses should be removed only in a clean environment after the
workers have thoroughly washed their hands. Evaluate continued
lens wear with the worker and the prescribing ophthalmologist or
optometrist. Encourage workers to routinely inspect their contact
lenses for damage and/or replace them regularly.
- Evaluate restrictions on contact lens wear on a case-by-case
basis. Take into account the visual requirements of individual
workers wearing contact lenses as recommended by a qualified ophthalmologist
or optometrist.
These recommendations are for work with chemical hazards. They do
not address hazards from heat, radiation, or high-dust or high-particulate
environments. References
Cerulli L, Tria M, Bacaloni A, Palmieri N [1985]. Hydrophilic contact
lenses and contamination in the work environment. Bollettino di Oculistica 64(1–2):299–305.
CFR. Code of Federal regulations. Washington, DC: U.S. Government Printing
Office, Office of the Federal Register.
Hejkal TW, Records RE, Kubitschek C, Humphrey C [1992]. Diffusion of
volatile organics through contact lenses. CLAO J 18(1):41–45.
LaMotte J, Smith G, Chang-Smith A [1995]. Absorption of ammonia by
high water content hydrogel lenses: an inexpensive method of analysis.
Optometry Vis Sci 72:605–607.
Nilsson EEG, Andersson L [1982]. The use of contact lenses in environments
with organic solvents, acids, or alkalies. Acta Ophthalmologica 60:599–608.
NIOSH [1978]. The standards completion program draft technical standards
analysis and decision logics. Cincinnati , OH : U.S. Department of Health,
Education, and Welfare, Public Health Service, Center for Disease Control,
National Institute for Occupational Safety and Health, NTIS No. PB–282
989.
NIOSH [2004]. NIOSH pocket guide to chemical hazards. Cincinnati ,
OH : Department of Health and Human Services, Centers for Disease Control
and Prevention, National Institute for Occupational Safety and Health,
DHHS (NIOSH) Publication No. 97–140.
|