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CONTINUING PROFESSIONAL DEVELOPMENT
Box 1. Common medicines which can cause
dry eyes 2,7
• Beta-blockers – topical and systemic
• Oral contraceptives
• Antidepressants – most commonly
• Topical non-steroidal anti-inflammatory
• Antipsychotic agents
Sarina is currently taking Endep
(amitriptyline) for depression.
Tricyclic antidepressants have been
implicated in dry eye syndrome.
cases, patients are not able to tolerate
adverse effects associated with tricyclic
In particular, the
anticholinergic effects such as dry eye, dry
mouth, blurred vision and urinary
retention, can be troublesome.
You refer Sarina to her doctor, for a
review of her current medicines, in light
of her symptoms of dry eye syndrome.
Various treatment options are available
for dry eye syndrome. Artificial tear
supplementation is the mainstay (first-
line) treatment option for all forms of
dry eye.2,9 Typically, these supplements
contain a combination of polymers,
electrolytes and buffering systems.2 The
excessive use of tear supplements which
contain preservatives may exacerbate
the symptoms of dry eye syndrome
(worsening ocular surface damage),
through a reduction in epithelial barrier
function.2,9 In patients with dry eye,
preservatives can have a marked toxic
effect on the eye due to reduced tear
clearance, which increases the contact
time of the toxin with the ocular
As such, where patients need
to use supplements more than four to
six times per day, a preservative-free eye
drop is recommended (see Table 1).2,9
Patients can typically expect
symptomatic relief within weeks of
using tear supplements, but this may
take up to 1 month for some patients.9
It is essential that patients are educated
Sarina has experienced sore, tired and
dry eyes for the past few months. There
are a number of potential causes of her
Dry eye syndrome is highly prevalent in
older adults, occurring in an estimated
5–30% of the elderly population.
Most predominantly, dry eyes occur
in patients who are >80 years (20%),
with patients <60 years having a low
prevalence (8.4%) of this disorder.
ageing eye, lacrimal gland dysfunction
leads to decreased tear production,
which results in a tear deficiency, and
subsequently dry eyes.
In addition, age-
related changes in hormone levels may
be associated with dry eye in the older
Sarina is 56 years of age, and as such
has a low prevalence of expected dry
eye syndrome associated with ageing. It
seems unlikely that ageing is the cause of
her current symptoms.
Common environmental irritants such
as chemical fumes and tobacco smoke
can result in dry eyes.
workplace factors, such as staring
at computer screens (resulting in
infrequent blinking) can also lead to dry
It has been shown that
intense computer work concentration
can increase the duration of the inter-
blink period, which can disrupt tear film
stability, leading to symptoms of dry
Sarina does not think she has any
issues with exposure to
environmental irritants. She does note
that her eye symptoms appear to be
exacerbated while at work, on the
computer. However, Sarina has worked at
a computer screen daily for over 20 years,
and she has never experienced this before.
In addition, she also experiences her
symptoms when not looking at the
computer screen. As such, it appears
unlikely that this is the cause of her current
Given the prevalence of dry eye
syndrome is greater in women, it has
also been suggested that sex hormones
may play a role in dry eye syndrome.
In particular, oestrogen has been
implicated in modulating a cascade of
inflammatory pathways affecting the
lacrimal gland, which can result in dry
The effect of oestrogen on dry eye
syndrome can be more noticeable after
menopause, where some women use
oestrogen replacement therapy.
Upon further questioning, you discover
that Sarina has not yet experienced
menopause. Her mother experienced a
very late menopause, and she is sure it will
happen in the next few years. It does not
appear that sex hormone imbalances are
causing her current symptoms.
Medical conditions such as Sjogren’s
syndrome, rheumatoid arthritis
and thyroid disorders have been
implicated in dry eye syndrome.
Sjogren’s syndrome is an autoimmune,
inflammatory disorder, which is most
common in middle-aged women.5
Patients with rheumatoid arthritis are
at a high risk of developing Sjogren’s
A common symptom of
this syndrome is dry, gritty and sandy
In thyroid disease (Hashimoto’s
thyroiditis), the eye protrudes to cause
an increased surface area.
cause the eyelids to open too widely,
increasing the chances of dry eyes.
Sarina assures you that she does not
suffer from any other medical
conditions, apart from depression and
high blood cholesterol. She has never been
diagnosed with an autoimmune disorder
or thyroid disease. It does not appear that
another medical condition is causing
Sarina’s current symptoms.
Some medicines can cause dry eyes
(see Box 1).
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