Artificial tears are over the counter
eye drops that are used to treat dry eyes. They work by adding volume
to the tear film. This can only occur, however, while the film
remains in contact with the surface of the eye. Artificial tears
require some agent that will allow them to remain in contact with the
eye surface. This is called a viscosity enhancing component.
Hydrogels are the viscosity enhancing component most commonly used in
artificial tears. Artificial tears may also contain glycine,
magnesium chloride, and zinc chloride, all of which are found in
natural tears. Sodium borate, a mild antiseptic, and other desirable
ingredients may also be included.
Despite the addition of viscosity
enhancing components, artificial tears still have a relatively short
retention time on the eye surface, limiting their effectiveness.
Scientists are currently experimenting with ingredients that have
some bio-adhesive properties, such as Systane, to lengthen the eye
surface contact time.
A wide selection of artificial tears
are available. The following guide will help you to select the right
type for your condition:
*** Moderately hypotonic artificial
tears has been shown to promote ocular surface disease healing in
severe dry eyes. Available hypotonic tears include: Thera Tears,
Hypotears and Akwa Tears.
(Br J Ophthalmol. 2002
Aug;86(8):879-84, Ophthalmologica. 2001 Mar-Apr;215(2):124-7)
*** Bicarbonate containing artificial
tears have been shown to promote healing in severe dry eyes.
Available bicarbonate containing tears include: Bion Tears,
(Arch Ophthalmol. 1995
Mar;113(3):371-8, Cornea. 1993 Mar;12(2):115-20)
*** Oil containing eyedrops (Refresh
Endura, Soothe) may be added if meibomian gland
dysfunction is present. These eyedrops will replenish the lipid layer
of the tear film and prevent tear evaporation.
*** In severe dry eyes and unresponsive
surface disease patients have significant visual impairment and
disability. In such patients the use of autologus serum eye drops
has been shown to help.
.(Br J Ophthalmol. 2004
May;88(5):647-52, Graefes Arch Clin Exp Ophthalmol. 2005 Mar 9)
Punctal occlusion is a medical
procedure in which the tear drain of the eye is closed. In the normal
course of events, tears leave the eye through two tiny openings in
the corners of the eye. A duct runs from there into the nose. In this
operation, small plugs are placed in the ducts, forcing the tears to
stay on the eye for a longer period of time. Punctal plugs may be
made of either collagen or silicon. Collagen plugs are intended to be
temporary and will dissolve within a matter of days. Silicon plugs
are permanent, though they can easily be removed by a physician.