REVIEW
AVAILABLE LENS CARE OPTIONS
—
Jason J. Nichols, OD, MPH, PhD*
ABSTRACT
The key functions of lens care solutions are to
clean and disinfect lenses, in addition to potentially making them more comfortable to wear.
Although tears contain numerous proteins and
lipids that are often deposited on contact lenses,
the quantity that is removed from the lens during
cleaning after wear varies with the constituent
material of the lens and the lens care solution
used. This article examines the effects of lens care
solutions on the tear film and the lens itself. This
article also reviews the efficacy of multipurpose
and hydrogen peroxide solutions with regard to
cleaning and disinfection, and addresses solution
reactions and other noninfectious complications
associated with contact lenses.
T
(Adv Stud Ophthalmol. 2008;5(3):76-78)
he key functions of a contact lens care
solution are to clean the lens by removing
proteins and lipids deposited by the tear
film, to disinfect the lens, and to make
wearing the lens as comfortable as possible. All 3 functions are closely interrelated in that a
cleaner lens is likely to be more comfortable and less
likely to be contaminated with microbes.
In this context, it is easy to understand how essential proper lens cleaning and disinfection are to patient
*Assistant Professor, The Ohio State University College
of Optometry, Columbus, Ohio.
Address correspondence to: Jason J. Nichols, OD, MPH,
PhD, Assistant Professor of Optometry and Vision Science,
Ohio State University College of Optometry, 320 West
10th Avenue, Office 560, Columbus, OH 43210-1280.
E-mail: jnichols@optometry.osu.edu.
76
comfort, which is a major determinant of satisfaction
and continued lens use. As revealed in a cross-sectional
survey of 730 current and previous contact lens wearers,
dry eyes and lens discomfort were the most common reasons for dissatisfaction and discontinuation, followed by
preference for a different modality, problems with the
modality, and inadequate vision correction.1
Before addressing the efficacy of lens care solutions
with regard to cleaning, disinfection, and comfort, it
would be helpful to examine the role of the tear film
in deposition, the stability of the tear film, and the
effects of lens care solutions on the tear film and the
lens itself.
THE TEAR FILM
PROTEIN DEPOSITION
The tear film contains numerous proteins (eg,
lysozyme, lactoferrin, lipocalin, albumin, transferrin,
and immunoglobulins) that have several biologic
effects on the surface of the eye, including hostdefense and antimicrobial function.2 When these proteins are deposited on contact lenses, they may become
denatured, which would increase the eye’s susceptibility to infection. Moreover, protein deposition might
alter the wettability of the lens surface, which reduces
tear film stability and coverage over the lens surface,
increases osmolality, decreases comfort, and can ultimately lead to increased expression of inflammatorymediator proteins that are associated with dry eye and
ocular surface disease.2
Deposition of proteins, lipids, and inorganic materials is also influenced by the characteristics of the constituent materials of contact lenses.3 For protein
deposition specifically, it is generally accepted that US
Food and Drug Administration group I lens materials
have the least amount of protein deposits (10–20
µg/lens) whereas group IV materials have the most (up
to 1000 µg/lens).3 In general, ionic, high water content
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materials attract more protein than nonionic materials.
The total amount of protein identified in silicone
hydrogel lens materials appears to be approximately
10 µg/lens, but again, may vary by specific material.3
To emphasize the importance of compliance with
lens care regimens, optometrists and other eye care
professionals should tell their patients that they are
prescribing—not merely recommending—a suitable
lens care regimen. This should be followed by explicit
instructions on proper use of the regimen.
accordance with the composition of the lens materials
and the quantity of tear film components they attract.2
For example, an analysis of tear film proteins
removed from 2 brands of silicone hydrogel lenses
(Acuvue Advance [Vistakon, Jacksonville, FL] and
O2Optix [CIBA Vision, Inc, Duluth, GA]) using 4
different multipurpose solutions (OPTI-FREE
Express [Alcon Laboratories, Inc, Fort Worth, TX];
ReNu with MoistureLoc [Bausch and Lomb,
Rochester, NY]; Complete Moisture PLUS [Advanced
Medical Optics, Inc, Santa Ana, CA]; and AQuify
[CIBA Vision, Inc, Duluth, GA]) found that more
than twice as much protein was removed from each
O2Optix lens than from each Acuvue Advance lens by
the care solutions.2 This finding may be related to the
different tear protein-binding affinities of the lens
polymers. The study also found that OPTI-FREE
Express removed the greatest amount of protein per
lens with both lens brands.
A similar analysis of protein deposition on the
same silicone hydrogel lens brands cleaned by AQuify
and ReNu with MoistureLoc found similar amounts
of protein deposition and a similar deposition proteome across both lens brands regardless of which
solution was used.3
The idea that a cleaner lens is a more comfortable
lens is borne out by a randomized, concurrently controlled trial comparing 2 multipurpose solutions in
362 group IV lens wearers with ocular symptoms.7
Subjects were fitted with a new pair of group IV lenses and randomly assigned to OPTI-FREE RepleniSH
(Alcon Laboratories, Inc, Fort Worth, TX) or ReNu
MultiPlus No Rub Formula (Bausch and Lomb,
Rochester, NY) for 4 weeks. All subjects recorded
comfort and ocular symptoms at days 0, 14, and 28.
Lens deposits were significantly lower in subjects using
OPTI-FREE RepleniSH, with mean scores for comfort and dryness significantly better at day 28, mean
scores for scratchiness and burning significantly lower
at day 14, and average lens wearing time significantly
longer at day 14.
CLEANING EFFICACY
Multipurpose solutions, which provide 1-step
cleaning and disinfection, are effective for the vast
majority of patients who wear soft contact lenses. In
general, these solutions vary in physical properties,
such as osmolality, viscosity, pH, and surface tension.6
They also vary in their ability to remove deposits in
ANTIMICROBIAL EFFICACY
Multipurpose solutions are formulated to provide
adequate disinfection. However, outbreaks of Fusarium
and Acanthamoeba keratitis in wearers of soft contact
lenses using certain multipurpose solutions have raised
some concerns about the antimicrobial efficacy of some
of these solutions. Although the outbreaks were associat-
TEAR FILM STABILITY
When applied to the eye, a contact lens divides the
tear film into 2 layers: the prelens tear film and the
postlens tear film.4 A stable tear film depends on the
surface of the contact lens and its physical interactions
with both tear film layers. A stable tear film is thought
to be necessary for comfortable contact lens wear.
If the structure of the prelens tear film is altered by
the presence of a contact lens, it will evaporate, resulting
in dehydration of the hydrogel lens and discomfort.4,5
The postlens tear film, by comparison, is thought to
enhance comfort by cushioning and lubricating the lens
on the conjunctival and corneal epithelium.4
A randomized study was conducted to determine
the impact of compositional differences in 2 multipurpose solutions on the tear film during contact lens
wear. Thirty-one subjects without dry eye symptoms
were included, and the study showed that the solution
containing the lubricant hydroxypropyl methylcellulose (HPMC) was associated with a thicker prelens
tear film than the solution that did not contain
HPMC.4 There were no differences between the solutions with regard to the thickness of the postlens tear
film. However, the latter solution, which contains surfactants targeted at improving the surface wettability
of lenses, was associated with less tear film thinning
(ie, evaporation).
MULTIPURPOSE SOLUTIONS
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ed with the use of specific solutions, other factors, such
as noncompliance (eg, solution reuse) and showering
while wearing contact lenses, cannot be overlooked as
contributors to increased risk for microbial keratitis.8,9
HYDROGEN PEROXIDE REGIMENS
Hydrogen peroxide-based solutions generally provide
disinfection only (with the exception of 1 solution—
ClearCare [CIBA Vision, Inc, Duluth, GA]); a separate
cleaning solution must be used first to remove protein
and lipid deposits from the lens. During disinfection with
hydrogen peroxide, the solution must be neutralized
before the lens can be reapplied to the eye. The time
required for neutralization varies from solution to solution, but can be as quick as 5 minutes and up to 30 minutes. The concern with this is that times at the lower end
of the range may not be long enough to provide adequate
disinfection. Other than disinfection, there is really little
to no scientific evidence that peroxide cleans lenses by
removing protein and lipid deposits. A peroxide-based
lens care system is still a good option for patients who
have a hypersensitivity reaction to any chemical ingredients associated with a multipurpose solution.
NONINFECTIOUS COMPLICATIONS
Frequent complications of contact lens wear are associated with improper lens care and solution uses, as well
as with lens spoilage.10 Complications can include solution toxicity,10 hypersensitivity,10 general inflammation,
staining of the bulbar conjunctiva,10 and corneal staining.11 However, some evidence suggests that there is not
a difference in corneal staining when comparing chemical and hydrogen peroxide-based care systems.11
Solution reactions may present with fine corneal
staining (with or without infiltrates), conjunctival
injection, and/or edema.10 If a solution reaction is suspected, lens use should be discontinued until the reaction is reversed. A different care regimen or a switch to
daily disposable lenses can then be initiated.
CONCLUSIONS
The key functions of lens care solutions are to clean
and disinfect lenses so that they are comfortable to
wear and free of deposits and microbes. The effects of
these solutions on the tear film and the lens itself are
important with regard to these key functions.
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Multipurpose solutions, which provide 1-step
cleaning and disinfection, are effective for the vast
majority of patients who wear soft contact lenses.
Hydrogen peroxide solutions generally provide disinfection only and often, a separate cleaning agent must
be used first; the solutions must be neutralized before
the lenses can be reapplied to the eye.
The most frequent complications of contact lens
wear are noninfectious and often associated with lens
care and solution noncompliance, as well as with lens
spoilage. Complications include solution toxicity,
hypersensitivity to solution ingredients, and corneal
staining, which often results from poor compliance
with the lens care regimen.
Educating patients about proper wear and care of
contact lenses is essential in improving compliance
with lens care regimens and should reduce the risk of
noninfectious and infectious complications.
REFERENCES
1. Richdale K, Sinnott LT, Skadahl E, Nichols JJ. Frequency of
and factors associated with contact lens dissatisfaction and
discontinuation. Cornea. 2007;26:168-174.
2. Emch AJ, Lee K, Sessler R, et al. Comparison of protein
extraction from silicone hydrogel lens materials and care
solutions. Presented at: Annual Meeting of the American
Optometric Association; Denver, CO; December 2006.
3. Green-Church KB, Nichols JJ. Mass spectrometry-based proteomic analyses of contact lens deposition. Mol Vis.
2008;14:291-297.
4. Nichols JJ, Mitchell GL, King-Smith PE. The impact of contact lens care solutions on the thickness of the tear film and
contact lens. Cornea. 2005;24:825-832.
5. Sharma A, Ruckstein E. Mechanism of tear film rupture and
its implications for contact lens tolerance. Am J Optom
Physiol Opt. 1985;62:246-253.
6. Dalton K, Subbaraman LN, Rogers R, Jones L. Physical
properties of soft contact lens solutions. Optom Vis Sci.
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7. Stiegemeister MJ, Friedrichs GJ, Hughes JL, et al. Clinical
evaluation of a new multi-purpose disinfecting solution in
symptomatic contact lens wearers. Cont Lens Anterior Eye.
2006;29:143-151. [Epub ahead of print].
8. Joslin CE, Tu EY, Shoff ME, et al. The association of contact
lens solution use and Acanthamoeba keratitis. Am J
Ophthalmol. 2007;144:169-180.
9. Chang DC, Grant GB, O’Donnell K, et al; for the Fusarium
Keratitis Investigation Team. Multistate outbreak of Fusarium
keratitis associated with use of a contact lens solution.
JAMA. 2006;296:953-963.
10. Optometric Clinical Practice Guideline. American
Optometric Association. 2nd ed. 2006. Available at:
http://aoa.org. Accessed March 26, 2008.
11. Nichols KK, Mitchell GL, Stonebreaker Simon KM, et al.
Corneal staining in hydrogel lens wearers. Optom Vis Sci.
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