CL DRY EYE MANAGEMENT
Contact Lens-related Dry Eye
you've diagnosed lens-related dry eye and its etiology, you can take steps toward
By Jerry R. Paugh, OD, PhD
lens-related discomfort remains a significant problem in contact lens practice.
In one survey (Pritchard, 1999) involving practices in Quebec, Canada, investigators
found that 34 percent of 1,444 patients discontinued wear, with 12 percent becoming
permanent dropouts. Interestingly, of the 488 initial dropouts, nearly half cited
discomfort/irritation and nine percent cited dry eye as the reasons for discontinuing
contact lens wear. Conversely, 23 percent of patients who resumed wear cited resolution
of discomfort as the reason for resuming wear. Thus, managing discomfort and lens
dryness continues to be an important goal to practitioners and industry alike, which
explains the plethora of new products and approaches designed to ameliorate
I'll summarize what's currently known about contact
lens-related dry eye, and I'll provide an overview of management approaches. Key
issues include the prevalence of dry eye discomfort, tear film differences between
tolerant and intolerant patients, the nature of dry eye disease among wearers and
the efficacy of various approaches to managing contact lens discomfort.
Prevalence of Lens Dryness
How common are dry eye and discomfort symptom
reports among contact lens wearers? Nichols et al (2005) conducted a recent investigation
of symptoms in a sample of patients that included clinical emmetropes, contact lens
wearers and spectacle wearers presenting for routine ophthalmic care. Of 893 responses,
52 percent of lens wearers reported dry eye disease, followed by 24 percent for
spectacle wearers and seven percent for clinical emmetropes. Moreover, the percentage
of patients who reported increasing frequency of dryness (from never to occasionally
or frequently) was greater for contact lens wearers than for the spectacle or emmetropic
groups. In a similar study, Guillon and co-workers (2002) found that 43 percent
of contact lens wearers reported dry eye symptoms compared to 15 percent of non-lens
From these studies and others, considerable
evidence exists that contact lenses induce dry eye symptoms in a significant number
of wearers. Although clinicians consider contact lenses to be an etiologic factor
in the development of dry eye (Lemp, 1995), much remains unanswered as to why symptoms
develop in lens wearers.
1: Classification of dry eye sub-types to date at SCCO.
Clinical and Tear Composition Characteristics of Intolerant Wearers
and co-workers (2002, 2003) examined tear compositional differences and clinical
tear parameters (non-invasive breakup time and tear volume) in two studies of tolerant
and intolerant patients. They examined lipid and lipocalin in tear film (2002) and
also proteins (2003). They defined intolerant patients as those who discontinued
soft lens wear because of dryness symptoms during the first six hours of wear.
Although they found no differences
in lacrimal gland secretory proteins (lactoferrin and lysozyme) in the 2003 study,
the 2002 results suggested that intolerant subjects had more degraded lipid compounds,
lipocalin and lipid enzyme activity compared to tolerant subjects. Interestingly,
the lipid layer appearance demonstrated no differences between the subject
groups in either study.
Also using lipid analysis, Guillon
and co-workers (2002) demonstrated that greater levels of tear cholesterol esters
were associated with a less stable lipid layer and increased discomfort symptoms.
Although further study is needed, it appears that identifiable differences exist
among wearers and that they may involve the lipid components of the tear film.
A key outcome of the work of Glasson
et al (2003) was that they found two easily measured tear parameters, tear volume
(via phenol red test and tear meniscus height) and non-invasive breakup time
(NIBUT), to be significantly reduced in the intolerant wearers. Similarly, in
a European study (Andres, 1987), 85 percent of intolerant lens wearers had fluorescein
breakup times of <10 seconds. This suggests that measuring these clinical parameters,
perhaps as part of a dry eye screening, may help identify patients who are likely
to experience lens wear difficulties.
Discomfort Due to Dry Eye
It's well known that contact lenses induce major
changes in the tear film including increased evaporation (Tomlinson and Cedarstaff,
1982), decreased stability (Faber, 1991) and decreased thickness (Nichols, 2005).
Although healthy, normal patients seem capable of achieving good comfort with lens
wear in spite of these changes, a significant number of patients find lens wear
intolerable. The causative factor might be underlying dry eye disease, particularly
in our aging population.
Figure 2. Meibomian
expression demonstrating a Grade 2 (thickened and opaque) secretion.
Clinic-based Dry Eye Sample Characteristics
For several years, the Center for Vision Research
at Southern California College of Optometry has undertaken studies related to dry
eye diagnosis, product evaluation and applied research into areas such as artificial
tear residence time and effect on vision. To evaluate some newer dry eye diagnostic
techniques, an ongoing screening study is underway that shows the general characteristics
of a clinic-based dry eye sample and of patients referred for lens intolerance that
we believe is related to a fundamental dry eye condition.
In terms of diagnosis, we classified subjects
by dry eye sub-type, as outlined by Pflugfelder et al (1998). The major categories
Sjögren's aqueous tear
Non-Sjögren's aqueous tear
Blepharitis (or inflammatory)
meibomian gland dysfunction (BLEPH)
Atrophic (or non-inflammatory) meibomian gland dysfunction (AMGD)
Mixture of aqueous tear deficiency
and meibomian gland dysfunction
Figure 1 presents the current status
of the screened individuals. One of the most striking findings is that overall,
approximately 75 percent have dry eye related to meibomian gland dysfunction, either
of the inflammatory or non-inflammatory type.
for the dry eye screening study involved referrals from the contact lens service,
which referred the patients because they were having significant difficulty in successfully
wearing their lenses. Table 1 provides characteristics of a small, recent sample
of these subjects. It appears that, as with the larger dry eye group, the majority
of intolerant contact lens patients (six out of seven) also have dry eye related
primarily to meibomian gland disease. This reinforces the idea that we must, as
clinicians, evaluate the meibomian glands as part of a broader dry eye workup in
Diagnosing Contact Lens-related Dry Eye
Before managing dry eye syndrome, we must establish
an adequate clinical testing system and attempt to assign a dry eye sub-type when
possible. From our experience to date, it seems reasonable to use the sub-type classification
scheme of Pflugfelder et al (1998). The main goal is to differentiate aqueous deficiency
(by use of Schirmer, fluorescein clearance test, and/or tear meniscus height) from
meibomian gland disease. Following are the minimal recommended tests, in order from
least invasive to most invasive:
Tear meniscus height using a reticule
eyepiece provides tear volume estimate.
Biomicroscopy, searching for
facial flush area injection, eyelid injection and lash loss all components
of inflammatory MGD.
Fluorescein or non-invasive
breakup time average three measurements, allowing 30 seconds rest between
Corneal staining using fluorescein
and yellow barrier filter recommended five-zone N.E.I. system (Lemp 1995)
and 0 to 4 scale.
Rose bengal or lissamine green
conjunctival staining stains mucus–free areas.
Meibomian gland expression (Figure
2) 0 to 4 scale as in Table 1.
Meibography using clinical transilluminator
(Figures 3 and 4) both lower lids, scale 0 to 4 as in Table 1.
Schirmer I test five
minutes, without anesthetic.
Instruct patients to not wear their
contact lenses for at least two days before dry eye evaluation to allow any lens-related
staining to clear. Also, patients should use no lubricant drops on the day of the
dry eye workup.
It's challenging to develop dry eye cut-off criteria for the various tests because
of the diversity of reported study approaches and dry eye populations. Many investigators
have adopted the criteria of the N.E.I./Industry workshop (Lemp 1995). The principal
criteria for diagnosing dry eye include symptoms, tear instability, evidence of
ocular surface damage and increased tear osmolality. With the exception of osmolality,
you can easily measure these parameters clinically. The criteria we use at our clinic
are based on the workshop principles, but because of recent literature reports,
we've tempered them more conservatively as follows:
Schein score >7/24 possible (Paugh 2003)
TBUT < seven seconds
Corneal fluorescein or
conjunctival rose bengal staining:
Cornea five-zone system
(0 to 4 scale); staining > 4/20 possible for all five zones
Conjunctiva six-zone system (0 to 4 scale); > 4/24 possible for six zones
Schirmer I sans anesthesia
< 5mm in five minutes
meibography using transilluminator to evert the lower lid.
Figure 4. Meibography demonstrating an area
of normal glands (letter a) and gland dropout (letter b).
Treating Dry Eye Conditions
You can successfully implement several approaches
for aqueous deficiency, using more aggressive measures for greater severity. Aqueous
deficiency treatments include conservation of existing tears (as with punctal plugs
first temporary plugs, then silicone plugs if effective), and replacement
of missing aqueous (artificial tears). If the deficiency is severe, add simultaneous
treatment with an anti-inflammatory such as Restasis (Allergan) or a soft steroid
(such as Lotemax, Bausch & Lomb). If you use a steroid, take care to first evaluate
the optic cup and measure intraocular pressure (IOP) in case of steroid response.
Thick nighttime lubricants or gels can assist healing of epithelial damage during
The ocular surface dwell time is influenced
by viscosity and possibly whether the polymer in the formulation is muco-adhesive.
Generally, residence time increases as the viscosity changes from a thin, watery
preparation, to higher-viscosity gels and ointments. Preliminary data in our laboratory
suggest that higher-viscosity formulations (Systane [Alcon] and Refresh Liquigel
[Allergan]) may last approximately twice as long as saline in the eyes of dry eye
subjects (Paugh 2004).
Managing MGD, whether inflammatory
or non-inflammatory, has at its center warm compresses and lid massage. Paugh et
al (1990) examined warm compress/lid massage therapy in a group of 21 problematic
soft lens wearers whose symptoms didn't seem related to care regimen or lens fit
problems. The researchers left one eye untreated and treated the fellow eye bid
with warm compress therapy. Under masked conditions, an investigator measured fluorescein
breakup time (TBUT) and found that the treated eyes had increased approximately
four seconds compared to no change for the untreated fellow eyes. Four seconds is
clinically significant and correlated with increased comfort of the treated eye.
Severe inflammatory MGD is relatively
rare in contact lens practice, but may be the most challenging condition when attempting
to rehabilitate such patients to resume contact lens wear. We've seen a handful
of such cases over the past few years that demonstrated several common features.
All eventually resumed contact lens wear.
patients had moderate to severe (grade 3 to 4 on a 0 to 4 scale) corneal staining,
greatly reduced TBUT (< five seconds) and moderate to severe meibomian gland
atrophy (> 50 percent of glands missing, with variable presentation of meibomian
cysts). In all cases, successful therapy included two to four months of warm compresses
and lid massage; topical (erythromycin ointment qhs) and systemic (minocycline or
doxycycline bid, 100mg/day) antibiotics; and topical steroid application (Lotemax
qid, monitor IOP and optic cup, then taper).
warm compress with lid massage remains the primary approach to MGD, other management
options have become available. These include lipid replacements (Soothe [Alimera
Sciences] or Refresh Endura [Allergan]) and possibly systemic ingestion of omega-3
fatty acids. We have limited clinical data on efficacy for this latter approach,
although the mechanism may be an anti-inflammatory effect on the ocular surface
Lens and Care Regimens
Although relatively recent, a growing effort is
underway by both lens and solution manufacturers to remedy the discomfort/dryness
issues related to lens wear. While much remains unknown, several studies have looked
at the impact of these efforts in improving lens wearing comfort and in vivo performance.
Fonn and co-workers (1999, 2003) examined
comfort over seven hours in symptomatic and asymptomatic wearers with several lenses
(omafilcon A, etafilcon A, nefilcon A and lotrafilcon A). They found that comfort
decreased significantly and equally with all materials over time only for the symptomatic
wearers. These findings suggest that lens comfort is more patient-specific rather
than material-specific, at least with these materials.
Thai and co-workers (2004) also examined
aspects of biocompatibility of several lens materials, using measures of tear physiology.
They studied polymacon, omafilcon A, phemfilcon A, balafilcon A and etafilcon A
in successful hydrogel lens wearers. They found no significant differences among
lens materials, with the exception of improved pre-lens tear film structure for
Another study by Thai and co-workers
(2002) examined the effect of a regimen adjunct (hydroxypropylmethylcellulose [HPMC]
in AMO's Complete Comfort formulation) on clinical measures of tear physiology in
normal wearers. They found no differences in tear evaporation or comfort, but significant
differences for tear film structure (measured with interference images) and pre-lens
tear stability (measured non-invasively) in favor of the HPMC formulation.
Taken together, there appear to be
subtle yet measurable improvements in patient acceptance and objective indicators
when using certain lens materials and care regimens. These options are worth exploring
for patients who suffer from dryness issues.
Where Do We Go From Here?
Dry eye symptoms are frequent in contact lens
wear and may induce significant numbers of patients to discontinue wear. Easily
measured clinical parameters such as tear stability and volume are associated with
contact lens intolerance and may point to a patient-specific origin. Dry eye in
general, and also that associated with contact lens intolerance, appears biased
toward meibomian gland disease.
Therefore, diagnosis of dry eye by sub-type,
in conjunction with appropriate management, appears vital to allowing these patients
to continue lens wear. We have limited, but definite evidence that certain lens
materials (omafilcon A) and possibly "moisturizing" care regimens may provide product-related
tools to manage contact lens-related dryness. Additional clinical research is needed,
using in vivo tear measures, to fully characterize recent material and regimen advances.
To obtain references for this article,
please visit http://www.clspectrum.com/references.asp and click on document #118.
Dr. Paugh is currently Associate Professor
and Associate Dean of Research at SCCO. He has conducted numerous research studies,
concentrating on the diagnosis and management of dry eye; the use of fluorometry
to examine epithelial barrier function, formulation residence time and drug delivery;
and the effects of contact lenses on corneal health.
Contact Lens Spectrum, Issue: September 2005