If you have chronically irritated and
watery eyes, you are not alone. Dry eye syndrome is one of the most common
problems treated by ophthalmologists. It is usually caused by a problem with
the quality of the tear film that lubricates the eyes. Fortunately, there are
various methods of controlling dry eye syndrome. A number of treatment options
are available to patients with dry eyes. Dr Somdutt Prasad, a noted
ophthalmologist and retinal specialist, explains the symptoms and treatment of
the condition.
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| Dry Eye |
What is dry eye?
Dry eye is a disorder of the tears that
results in ocular discomfort and visual disturbance. It can occur for a variety
of reasons, and seems to be increasing in frequency. If not managed properly it
can lead to ocular surface damage from increased osmolarity of the tear film
and chronic inflammation of the cornea and conjunctiva. Dry eye does not simply
mean dryness. Dry eye can be a result of insufficient tear production, as well
as abnormal tear composition or increased tear evaporation.
It is common in people working for long
hours in front of a computer monitor mainly because the blink rate, which
should be 15 times a minute, reduces a lot when one is concentrating on a
monitor. It is useful to take a short break every hour or so and keep your eyes
closed for a few minutes. Dry eye is also common after eye surgery, especially
refractive corneal surgery like LASIK. Luckily, most of these can be treated
adequately with lubricating eye drops, a whole range of which are available
readily.
Tears are comprised of three layers. The
mucus layer coats the cornea, the eye’s clear outer window, forming a
foundation so the tear film can adhere to the eye. The middle aqueous layer
provides moisture and supplies oxygen and other important nutrients to the
cornea. This layer is made of 98 percent water along with small amounts of
salt, proteins and other compounds. The outer lipid layer is an oily film that
seals the tear film on the eye and helps to prevent evaporation.
In addition to lubricating the eye,
tears are also produced as a reflex response to outside stimulus such as an
injury or emotion. However, reflex tears do little to soothe a dry eye, which
is why someone with watery eyes may still complain of irritation.
The commonest reason for dryness is
simply the normal aging process. As we grow older, our bodies produce less oil —
60% less at age 65 then at age 18. This is more pronounced in women, who tend
to have drier skin then men. The oil deficiency also affects the tear film.
Without as much oil to seal the watery layer, the tear film evaporates much
faster, leaving dry areas on the cornea. Many other factors, such as hot, dry
or windy climates, high altitudes, air-conditioning and cigarette smoke also
cause dry eyes. Many people also find their eyes become irritated when reading
or working on a computer.
Stopping periodically to rest and blink
keeps the eyes more comfortable. Contact lens wearers may also suffer from
dryness because the contacts absorb the tear film, causing proteins to form on
the surface of the lens. Certain medications, thyroid conditions, vitamin A
deficiency, and diseases such as Parkinson’s and Sjogren’s can also cause
dryness.
Symptoms
Common symptoms are:
- Itching
- Burning
- Irritation
- Foreign body sensation - 'feeling of
something in the eye'
- Redness
- Blurred vision that improves with
blinking
- Excessive tearing
- Increased discomfort after periods of
reading, watching TV, or working on a computer.
Paradoxically a dry eye can lead to
tearing. Glands in the eyelids (the Meibomian glands) secrete an oily material
that lines the tears covering the cornea, the clear and extremely sensitive
window at the front of the eye. The oily secretion retards the evaporation of
the tear film in between blinks. If these glands do not function properly (e.g.
in blepharitis), the tear film evaporates quickly leaving the sensitive cornea
exposed. The tear glands then produce an excessive volume of tears as a reflex
which overwhelms the tear drainage system (as in emotional crying). This often
leads to confusion with patients failing to understand why they have been
prescribed artificial tears to improve their symptoms!
Treatment
Most people who suffer from dry eyes
find relief from using artificial tears on a regular basis. Some of these
products are watery and alleviate the symptoms temporarily; others are thicker
and adhere to the eye longer. Preservative-free tears are sometimes recommended
because they have fewer additives that could potentially irritate. When
choosing an artificial tear preparation it is often useful to try a few
different brands. Patients often find that they are more comfortable with a
particular brand of artificial tear preparation. Also, patients often find that
a watery preparation is more useful during the daytime (eg Systane Ultra, Tears
Naturalle, Refresh, Ecotears, Just Tears) as they do not cause blurring, but a
thicker solution (eg Genteal Gel, Lubrex Gel) is useful before going to sleep
as it provides a longer period of relief.
If artificial tear preparations do not
provide adequate relief it is useful to close the opening of the tear drain in
the eyelid with special inserts called punctal plugs. This works like closing a
sink drain with a stopper. These plugs trap the tears on the eye, keeping it
moist. This can be done semi-permanently with a silicone plug which can be removed
if required. By reducing drainage, more of your natural tears will remain in
your eye to protect your vision and provide necessary nutrients to protect your
eye.
There are also simple lifestyle changes
that can significantly improve irritation from dry eyes. Make a conscious
effort to blink frequently – especially when reading or watching television.
Avoid rubbing the eyes. This only worsens the irritation.
