Transcript The Use of Sodium Hyaluronate Gel 0.3% in the Management of

THE USE OF SODIUM HYALURONATE GEL 0.3% IN THE MANAGEMENT OF POST-KERATOPLASTY PATIENTS,
AND PATIENTS WITH CHRONIC REFRACTORY DRY EYE AND OTHER OCULAR SURFACE PROBLEMS.
Prof. Clive Peckar. Dept. Ophthalmology. Warrington. UK.
Purpose:
Fig.1
Topical Sodium Hyaluronate (SH) 0.18% has been used in the management
of Dry Eye Syndrome (DES) and corneal surface problems. Associated with
symptoms of ocular discomfort, dryness, scratchiness, burning, soreness
and grittiness, the underlying mechanism of DES is still unclear. Therefore,
treatment is based on symptom relief rather than cure. Because of its ability
to stabilise the tear film and promote epithelial healing via its preservativefree, specific muco-adhesive, water retentive, and viscoelastic properties,
0.18% SH has proved effective in reducing subjective symptoms intensity on
VAS and objective corneal staining with fluorescein.
Moderate to severe dry eye cases often require hourly or half hourly
treatment with ocular lubricants, but despite this regime many patients
Results
remain symptomatic. As rapid and recurrent blinking – a characteristic
Condition and No' of Patients Presenting
symptom of more pronounced DES - correlates with a rapid tear film break
up time (TFBUT), the manufacturers of Vismed carried out research to find if
different concentrations of topical SH might prove more effective in retaining
tear film integrity.
anterior basement membrane dystrophy
The non-Newtonian behaviour of tear film reduces viscosity as shear rate
longstanding facial palsy
increases, this viscoelasticity is emulated by Vismed (fig. 1).The in vitro study
rheumatoid corneal melt
by Nakamura et al (1993) investigated the potential for hyaluronan (0.1%,
longstanding herpes simplex keratitis
0.5% and 1.0%) to retain water. A significant (p<0.05) difference was found
between vehicle and all of the SH concentrations assessed, and a dosepost penetrating keratoplasty with post surgical
bullous corneal endothelial failure
dependent increase in water retention was observed.
post penetrating keratoplasty with post surgical
corneal flattening
Based in part on these findings, a highly viscous 0.3% preservative-free
Sjogren’s Syndrome
Sodium Hyaluronate Gel was introduced in 2004 for the effective
severe ‘dry eye syndrome’
management of persistent and severe symptomology associated with DES.
This paper describes 20 patients who attended with severe dry eyes and
were treated with 0.3% Sodium Hyaluronate in order to achieve a more
stable pre-corneal tear-film, and thus a relief of symptoms.
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No' of Patie nts
Patients and Methods:
Location: Warrington Hospital and Spire Cheshire Hospital, Warrington
UK.Patients attending between May 2004 and January 2008
20 Patients with severe kerato-conjunctivitis sicca, who remained
symptomatic following puncto-canalicular occlusion with intra-canalicular
implants (SmartPlugs™) and regular instillation Sodium Hyaluronate
0.18% drops (Vismed™), were changed to Sodium Hyaluronate 0.3%
(Vismed Gel™).
Conclusion:
Sodium Hyaluronate 0.3% (Vismed Gel™) is effective, safe, and
well tolerated in treating symptoms associated with severe “dry
eye syndrome”, and represents a valuable addition to the
Ophthalmic Specialist’s armamentarium for the management of
patients with severe dry eyes.
The tears produced by the glands in the secretory system combine in the eye
to form a thin tear film that covers the corneal epithelium
A stable precorneal tear film is vital for the health of the cornea as well as the
optical quality of the cornea
During blinking, the rate of shear can be very high which, if transmitted to the
epithelial surfaces, can cause cell damage
The viscoelastic properties of the tear film lubricate and cushion the eye during
all types of eye movement
The non-Newtonian behaviour of tear film reduces viscosity as shear rate
increases
Its elastic component can help absorb energy during rapid eye movements
In a healthy eye, the precorneal tear film begins to evaporate after 15 to 30
seconds between blinks. If the tear film isn’t regenerated, dry spots can form
on the cornea, leading to problems such as dry eye
Role of the mucus layer
The mucus layer plays a vital role in tear film stability and
allows the aqueous layer to adhere to the epithelial cells of
the cornea. By lowering the surface tension between these
two layers, it acts as a wetting agent as well as a stabilising
agent for the thin precorneal tear film between blinks.
The mucus strands trap desquamated epithelial cells,
excessive lipid contamination and debris (especially
microorganisms). These are then removed from the eye in
the aqueous layer during the blinking process.
Mucus displays non-Newtonian and elastic behaviour
(viscoelasticity). This viscoelasticity is emulated by the main
component in Viscoseal – Hyaluronic Acid. Mucus is
relatively thick and clings to the surface of the eye when the
eye is at rest; however, when the eye blinks the mucus layer
becomes much thinner and spreads easily over the surface,
providing lubrication. The elastic properties of the mucus
help this layer to absorb energy during the blinking
process.Rate of shear = the relative velocity of the lid and
eyeball, divided by the thickness of the fluid layer.
During blinking, the rate of shear can be very high. If
shearing forces are transmitted to the epithelial surfaces,
cell damage and painful dragging sensations may occur.
The non-Newtonian behaviour of tear film can help by
reducing viscosity as the shear rate increases. The elastic
component of the tear film helps it to absorb energy during
blinking. In combination, the viscoelastic properties of the
mucus strands (in the aqueous layer) and the mucus gels
(close to the epithelial surface) cushion and lubricate the
eye during all types of eye movement.
Hydrophilic side
Hydrophobic side
A vesicle-like foamy secretion is evident along the lower lid margin. The tear film
break-up time was reduced to less than 2 seconds. The patient had a pronounced dry
eye syndrome with disturbance of the composition of the tear film
Due to its amphiphilic structure, HA can trap
and retain large volumes of water.