Download Contact lens overwear syndrome

Andrew S. Gurwood OD, FAAO
Contact lens overwear syndrome
(immobile lens syndrome)
Patients who over-extend contact lens
wearing time or improperly use contact
lenses in a closed eye environment
(during sleep), run the risk of developing
contact lens overwear syndrome
(contact lens-induced acute red eye,
CLARE, or tight lens syndrome)1-5
(Figure 1).
Signs and symptoms
Often patients are awakened early in the morning
with unilateral ocular pain accompanied with
ocular redness, tearing, decreased vision and
photophobia. The classic presentation possesses
distinct clinical signs including a unilateral acute
corneal inflammatory episode, with mild to
moderate blepharospasm, severe conjunctival
and limbal hyperaemia, corneal oedema, corneal
infiltration and ocular pain1,5. If the patient does
not or cannot remove the contact lens,
biomicroscopic examination often uncovers a
contact lens with minimal to no movement and
debris trapped underneath the optic zone
(Figure 2). Typically, upon lens removal, corneal
epithelial staining is minimal and imprinted in
the pattern of the visualised debris1. Corneal
infiltration (white blood cells in the epithelium
or anterior stroma) may be present but is usually
not complicated by overlying epithelial disruption
(ulceration)1.
Pathophysiology
When the eye is open, under normal conditions,
it receives its oxygen supply (21%) directly from
the atmosphere1. When the eye is closed or
covered by a contact lens, oxygen is supplied to
the anterior corneal surface via diffusion from
the vascular capillary plexus of the upper
palpebral conjunctiva1. Contact lenses, hydrogels
in particular, can reduce the amount of oxygen
which reaches the anterior corneal surface.
Contact lens movement, oxygen permeability
(Dk/L), thickness profile and wearing schedule
all influence corneal oxygen availability and
physiology1-5.
The aetiology of contact lens overwear
syndrome remains controversial. Corneal hypoxia,
toxins released by contaminants trapped
underneath a stagnantly moving
lens during closed eye wear, and poor physiology
secondary to tightening of the lens/base curve,
corneal relationship or combinations, are all
postulated as potential aetiologies1,2,5.
cornea will uncover the presence of gross
epithelial defects, corneal oedema,
subepithelial infiltration and anterior chamber
reaction. Sodium fluorescein staining of the
epithelial surface will expose areas of
epithelial compromise and allow the clinician
to rule out ulceration1,5.
The initiation of a cycloplegic agent is
recommended. Choice of cyclopentolate, isopto
hyosine, homatropine or atropine is dictated
by severity. If there is significant staining of
the corneal epithelium, or an overlying
epithelial defect above an area of infiltration,
topical antibiotic therapy, QH-Q4H should be
initiated using an aminoglycoside (Gentamicin,
Tobramicin) or fluoroquinolone (Ciloxan,
Ocuflox, Quixen or Chibroxan)1. If corneal
subepithelial infiltration is present, without
complications, patient education and
treatment with ocular lubricants or hypertonic
solutions, along with monitoring until
resolution, are all that are required. The
addition of a topical steroidal preparation,
such as Lotomax, Alrex, Pred Forte or Pred
Mild (bid/qid) is an available option
depending upon the patient’s visual disability,
discomfort and the severity of the
inflammation.
Follow up should be started as weekly and
tapered as resolution is observed. Contact lens
wear may be resumed following resolution, and
a refit should be considered.
Clinical pearls
Steroids should not be used in situations
involving open corneal epithelium. The nonsteroidal anti-inflammatory preparations work
well for reducing pain but are not an option to
steroids when considering the reduction of
inflammation. Further, while many elect to use
combination medicines in these circumstances,
using agents individually gives greater
flexibility. Topical antibiotics should not be
reduced, while topical steroidal preparations
should. This cannot be accomplished with the
same efficiency if a combination is used. If an
ulcer is present, culturing may be necessary.
Recent studies3,4 have shown that extended
wear usage increases the risk of CLARE.
Further, patients who have endured an episode
are susceptible to repeat occurrences1. Patients
who have had a contact lens associated acute
red eye should be educated and refitted with
daily wear lenses1.
Management
Clinical management begins with cessation of
contact lens wear. Visual acuities, along with an
evaluation of the pain response to extraocular
muscle movement and to light exposure
(photophobia), will provide clues to the degree
of inflammation. Light biomicroscopy of the
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Note
The author practises in the USA where he has
full therapeutic rights as an optometrist. In
the UK, the procedures in this article would
need to be undertaken in a co-management
role with an ophthalmologist.
Figure 1 Diffuse injection, corneal
oedema and nasal subepithelial
infiltration seen following CLARE
Figure 2 Corneal oedema without
extensive conjunctival injection; a
different presentation of CLARE –
consistent with hypoxia secondary to
tight lens (tight lens syndrome or
immobile lens syndrome)
References
1. Swarbrick, HA, Holden, BA (1994)
Complications of Hydrogel Extended Wear
Lenses. In: Silbert, JA, Anterior Segment
Complications of Contact Lens Wear.
Churchill Livingstone, New York, 289-316.
2. Allansmith, MR, Ross, RN (1995) Giant
Papillary Conjunctivitis. In: Tasman,
W, Jaeger, EA Duane’s Ophthalmology on
CD-ROM. JB Lippincott, Philadelphia,
1-15.
3. Epstein, AB, Freedman, JM (1994) The
impact of overnight wear on the risk of
contact lens-associated ulcerative
keratitis. Archives of Ophthalmology
112 (2): 186-90.
4. Schein, OD, Buehler, PO, Stamler, JF,
Verdier, DD, Katz, J (1994) The impact of
overnight wear on the risk of contact lensassociated ulcerative keratitis. Archives of
Ophthalmology 112 (2): 186-192
5. Brennan, NA, Bruce, AS (1993) Imobile
Lens Syndrome. In: Brennan, NA, Bruce,
AS A Guide to Clinical Lens Management.
CIBA Vision Management, Zurich,
Switerland, 37.
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