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Date: Mon, 15 Nov 2004 08:17:33 -0500
Reply-To: al.muehlhausen**At_Symbol_Here**CIBAVISION.NOVARTIS.COM
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: al.muehlhausen**At_Symbol_Here**CIBAVISION.NOVARTIS.COM
Subject: Re: Goggles and Contact Lenses
Comments: To: ACTSNYC**At_Symbol_Here**CS.COM
Here is a well written position paper by Karen Messana that we rely on for
guidance regarding issues surrounding the use of contact lenses in our
Research Laboratories.
Al Muehlhausen
Health, Safety, and Environmental Officer
Corporate Headquarters and R&D
CIBA Vision Corporation
Years of lens use and research studies have settled the issue: Wearing
contacts in a chemical environment or other environments doesn't increase
the risk of injury.
by Karen Messana
Safety professionals should no longer take the position of prohibiting the
wearing of contact lenses in the workplace, and the requirements to wear
PPE for "eye hazardous" situations should be no different for wearers than
non-wearers. Why can this be said? Because after 40 years of contact lens
use, there is no well-documented information that wearing contacts
increases the risk of injury over that of non-wearers and wearers of
spectacles, whether we are talking about foreign bodies, or chemicals, or
other eye hazard sources.
Studies have looked at eye hazards such as flying metal/dust particles,
chemicals, and radiant energy such as UV and IR. (1, 2, 3) Specific
chemicals tested include acetone, ammonia, acetic acid, creosol,
butylamine, toluene, xylene, diethyl ether, trichloroethylene, sodium
hydroxide, sulfuric acid, hydrochloric acid, and tear gases.(4, 5, 6) In
each instance, none documented a greater risk of injury to the contact
lens wearer over the non-wearer--and in most, a protective effect was
noted. In addition, there is a paucity of reported or anecdotal evidence
of injuries resulting from contact lens use in the workplace.(7, 8) A
review of 7,000 contact lens-related abstracts on the PubMed Web site
spanning more than 30 years resulted in only a handful of studies or
reviews regarding contact lenses in the workplace. None resulted in
conclusions that wearing contacts in a chemical environment or other
environments increased risk of injury.
Studies show that for each instance of eye injury demonstrated to be more
severe due to wearing contact lenses, there are about 30 instances where
similar exposure circumstances prevented or reduced injuries, or at least
did not increase the severity of the injury, when the person was wearing
contact lenses.(9, 10, 11) Put another way: Every time we prohibit someone
from wearing contact lenses in an eye hazardous environment, we increase
our chances of that person experiencing an eye injury greater than would
have occurred if an "accident" happens. Logic dictates that wearing
contacts should be encouraged in such environments, not discouraged.
The Seat Belt Analogy
We all know it wouldn't be hard to find a study or two that indicated that
some people suffer more injury from wearing a seat belt than from not
wearing a seat belt when a collision occurs. However, the vast majority of
the time, the seat belt user is either protected from any injury, the
severity of the injury is reduced, or there is no difference in injury
outcome when compared to a non-seat belt wearer. Knowing this, we choose
to wear the seat belt because of its overall beneficial effect. Replace
the words "seat belt" in this paragraph with "contact lenses," and the
same substantiated statement of benefit can be made.
So where have our concerns about contact lenses in the workplace come
from? When contact lenses first became an issue of concern in the
workplace, there were no guidelines or data to consider in assessing risk
associated with their use. Based on worst case scenarios, perceived risks,
and problems encountered by new wearers of contact lenses, conservative
positions were taken by authoritative bodies that prohibited contacts lens
use in industrial environments, even when additional eye protection was
worn. At the time, the primary fears and perceived risks included
statements such as:
? Foreign bodies, normally washed away with tears, could become trapped
under the lens and thereby abrade the cornea (the cornea is the part of
the eye we see through, and contacts fit directly over the cornea, hence
the concern).
? Chemicals could absorb through the lens, resulting in subsequent injury
to the cornea.
? Chemicals entering the eye could cause eyelid spasms that would prevent
removal of the lens for flushing.
In addition, two widely misreported incidents fueled concerns about the
hazards of contact lenses and lent credibility to unsubstantiated beliefs.
The first was the 1967 arc flash that supposedly fused the worker's
contact lenses to his eyes, and when the lenses were removed, the cornea
peeled off and he was blinded.(12)
In reality, the worker wore his lenses too long and suffered a corneal
ulceration, which healed completely in a couple of days. He had been
exposed to an electrical arc the same day without incident, hence the
source of the rumor.
The second incident involved a widely-read industrial ophthalmologist who,
while proposing a restrictive contact lens use policy, used a chemical eye
injury incident to support his position.(13) The incident involved a 50
percent caustic splash to an engineer's face while wearing contact lenses
with goggles; although the engineer suffered eye injury, there was no
documentation of how the contacts contributed to the injury, if at all, or
what type of goggles were involved.
Foreign Bodies, Chemicals
With regard to the concern of foreign body being under a lens, studies and
anecdotal situations have proven these beliefs to be unsubstantiated.(1,
2) The theory of what actually happens is that the normal adhesion force
of the lens to the eye surface prevents a foreign body from entering the
space under it, and particles are easily removed by normal tearing,
blinking, and cleaning.
Although studies have shown that some chemicals can be absorbed into
certain soft lenses, the studies have not demonstrated that the chemicals
reach the other side and injure the cornea. Typically, the contact lens
initially acts as a sponge/vacuum, keeping the chemical in its core and
away from its surfaces.(11, 14) In addition, studies imply that tears
attract the absorbed chemical to come back out and away from the lens.
Furthermore, it is unlikely chemicals of concern (corrosives) are
absorbing into the lens fast enough to become trapped under the lens
without plenty of notice ahead of time to the wearer. Imagine being
splashed in the eye with a corrosive or vapors slowly accumulating their
concentration in the lens. The eye pain and irritation would necessitate
prompt flushing action, with subsequent removal of the lens. In addition,
when the eye is chemically attacked, studies postulate that the eye spasms
and literally sucks the lens against the corneal surface, preventing the
chemical from entering that space for some period of time.(15)
Meanwhile, the person would be flushing the eye with water, greatly
diluting any residual chemical. The contact lenses would have protected
the cornea from the immediate, direct contact of the highest concentration
of the substance.
What Do the Experts Say Today?
The American Chemical Society's Committee on Chemical Safety: "In many
workplaces, where hazardous chemicals are used or handled, the wearing of
contact lenses is prohibited or discouraged. A good number of these
prohibitions are traceable to earlier statements based on rumors and
perceived risks. A careful study of the literature has refuted these
risks. Recent studies and experience have suggested that, in fact, contact
lenses do not increase risks but can actually minimize or prevent injury
in many situations. It is the consensus of the committee that contact
lenses can be worn in most work environments provided the same approved
eye protection is worn as required of others in the area. It should be
stressed that contact lenses, by themselves, do not provide adequate
protection in any environment in which the chance of an accidental splash
of a chemical can reasonably be anticipated."16
The American Optometric Association: "An evaluation of the published
material, including laboratory and animal studies, and well documented
case reports, indicates that contact lenses may be worn safely under a
variety of environmental situations including those which, from a
superficial evaluation, might appear hazardous. Indeed, some types of
contact lenses may give added protection to spectacle lens and
non-spectacle lens wearers in instance of certain fume exposure, chemical
splash, dust, flying particles, and optical radiation. The evidence also
refutes the claims that contact lenses negate the protection provided by
safety equipment or make the cornea more susceptible to damage by optical
radiation. . . . Regulations limiting the wearing of contact lenses in any
given circumstances must be scientifically defensible and effectively
enforceable. They should not be based on perceived hazards, random
experience, isolated unverified case histories, or unsubstantiated
personal opinions."(17)
OSHA's preamble for the Final Rule on PPE in 1994 states: "OSHA believes
that contact lenses do not pose additional hazards to the wearer and
additional regulation is unnecessary."
In summary, it is reasonable to allow the use of contact lenses in any
area that the unaided eye is permitted. It is not necessary to require
removal of contact lenses prior to entering eye hazardous environments.
Instead, require the use of PPE and if PPE is to be worn, then, base it on
the assessment that all persons need to wear the PPE, not just contact
lens wearers.
Overall, safety professionals can ensure that eye protection policies are
in writing, a PPE hazard assessment is conducted, proper eye protection is
designated, contact lens users are identified, emergency and first aid
procedures are addressed, and contact lens wearers are educated and
trained. In addition, these wearers should be encouraged to have a spare
set of corrective lenses available on the job.
References
1. Nilsson, S.E.G., P. Lovsund and P.A. Oberg: Contact Lenses and
Mechanical Trauma to the Eye. Acta Ophthalmol . 59:402-408 (1981).
2. Nilsson, S.E.G., H. Lindh and L. Andersson: Contact Lens Wear in an
Environment Contaminated with Metal Particles. Acta Ophthalmol . 61:882-888
(1983).
3. Owen C.G, T.H. Margrain T.H., E.G. Woodward: Use of Contact Lenses by
Firefighters: Part 2. Clinical Evaluation. Ophthalmic Physiol Opt . May; 17
(3):205-15 (1997).
4. LaMotte, J., G. Smith, A. Chang Smith: "Absorption of Ammonia by High
Water Content Hydrogel Lenses: An Inexpensive Method of Analysis"; Optometr
y and Vision Science , 72:605-607 (1995).
5. Aalphen, C.C. Kok-van, W. van der Lindern, R. Visser and A.H. Bol:
Protection of the Police Against Tear Gas with Soft Lenses. Mil Med . 150(8
):451-453 (1985).
6. Hejkal T.W., R.E. Records, C. Kubitschek, C. Humphrey: Diffusion of
Volatile Organics Through Contact Lenses. CLAO J . Jan 18(1):41-45 (1992).
7. Hirschfelder, D.: Contact Lenses in the Workplace: The Dilemma. Sight Sa
v. Rev . 52(1):14-18 (1983).
8. Contact Lens Association of Ophthalmologists, Inc.: "Position
Paper--Industrial Safety." New Orleans , LA , 1979.
9. Blais, B.R.: "The Use of Contact Lenses in an Industrial Environment"
(unpublished manuscript). Bethesda , Maryland : Uniformed Services
University of the Health Sciences, April 1985.
10. Wesley, N.K.: Chemical Injury and Contact Lenses. Contacto . 10(3):15-2
0 (1966).
11. Nilsson, S.E.G. and L. Andersson: The Use of Contact Lenses in
Environments with Organic Solvents, Acids, or Alkalis. Acta Ophthalmol . 60
:599-608 (1982).
12. Contact Lens Association of Ophthalmologists, Inc.: Policy Statement
on Arc Welding and Contact Lens Wear. Cont. Intraocular Lens Med. J . 9(4):
343 ( July 23, 1983 ).
13. Kuhn, H.S.: Contact Lenses-Threat to Vision? Nat. Saf. News . June:23 (
1961).
14. Tredici, T. J. and W.J. Flynn: The Use of Contact Lenses by USAF
Aviators. Avia., Space, Environ. Med . 58:438-443 (1987).
15. Guthrie, J.W. and G.F. Seitz: An Investigation of the Chemical Contact
Lens Problem. J. Occup. Med . 17(3):163-166 (1975).
16. www.pubs.acs.org/cen/safety/19980601.html
17. www.aoanet.org/ia-cl-ind-environ.html
Karen Messana ( kmessana**At_Symbol_Here**trinitymfg.com ), CSP, MS Industrial Hygiene, has
21 years of safety experience. She
currently is the EHS Manager for a chemical manufacturer. Messana wrote
her master's degree technical paper on the workplace use of contact lenses
in 1989 and has continued to follow the issue.
http://www.safetydirector.com/ http://www.safetydirector.com/
=A9 Copyright 2001 Stevens Publishing Corporation
5151 Beltline Road, 10th Floor, Dallas, Texas 75240
ACTSNYC**At_Symbol_Here**CS.COM
Sent by: DCHAS-L Discussion List
11/14/2004 02:59 PM
Please respond to ACTSNYC
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
cc: (bcc: Al Muehlhausen/CV/Novartis)
Subject: Re: [DCHAS-L] Goggles and Contact Lenses
I agree with use of contact lenses as well.
We mustn't oversimplify splash goggles either. There are vented, indirect
vented, and unvented splash goggles. I need to recommend even different
types
of splash goggles for different purposes in my work. Eye protection is
not
Monona Rossol
In a message dated 11/13/04 6:21:08 PM Eastern Standard Time,
Labsafe**At_Symbol_Here**AOL.COM
writes:
> Phil is absolutely right. Chemical splash does need goggles. But the
> problem is that many folks can't, don't, or won't distinguish between
impact
> and
> chemical splash goggles.
>
> So, saying goggles in simply insufficient. One must say chemical splash
> goggle for a chemical splash. And ANSI/ASSE could do us all a big favor
by
> asking
> the manufacturer to put the selection chart letter after the Z-87.1 to
> indicate the type of device.
>
> Concerning contact lenses, they do it for good reason. Six years ago,
after
> five years of study, the ACS Council Committee on Chemical Safety joined
> other
> major organizations (Prevent Blindness America, American Optometric
> Association) and many companies (Dow, 3M, and DuPont) by agreeing that
> contact lenses
> are acceptable as long as all the other necessary eye protection is
worn.
>
> So, I for one am not the least bit upset about contact lens use and very
much
> agree with the ACS position. ... Jim
>
>
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