In today’s article, I would like to talk to you about the science behind
the ingredients in artificial tears. These are the over-the-counter eye
drops for treating dry eye disease. This post will help you to
understand the differences between different dry eye drop
ingredients and will help you choose the artificial tears that work
best for you.
the ingredients in artificial tears. These are the over-the-counter eye
drops for treating dry eye disease. This post will help you to
understand the differences between different dry eye drop
ingredients and will help you choose the artificial tears that work
best for you.
Without further ado, let’s talk about the ingredients in artificial tears.
The ingredients of artificial tears can be categorized into three
groups:
The ingredients of artificial tears can be categorized into three
groups:
- Active Ingredients
- Inactive Ingredients
- Preservatives
1. Active Ingredients
The active ingredients are the agents that have been approved by the FDA to
be used in artificial tears to provide lubrication to the eye. There
are three main categories of active ingredients in artificial
tears.
be used in artificial tears to provide lubrication to the eye. There
are three main categories of active ingredients in artificial
tears.
- Astringent
- Demulcent
- Emollient
Astringent
The most commonly used ophthalmic astringent is zinc sulfate. Two
common brands of dry eye drops that contain zinc sulfate are
Clear eyes drop made by prestige consumer healthcare and
Visine made by johnson &
johnson.
common brands of dry eye drops that contain zinc sulfate are
Clear eyes drop made by prestige consumer healthcare and
Visine made by johnson &
johnson.
Zinc sulfate can help reduce the burning and itching sensation from
exposure to the pollutants in the air by reducing the mucus on the
surface of the eye. So it can help reduce some allergy symptoms but
zinc sulfate is not very effective in lubricating the eye compared to other
active ingredients. So it is not a top active ingredient in artificial tears
that I recommend for my patients to treat their dry eye disease.
exposure to the pollutants in the air by reducing the mucus on the
surface of the eye. So it can help reduce some allergy symptoms but
zinc sulfate is not very effective in lubricating the eye compared to other
active ingredients. So it is not a top active ingredient in artificial tears
that I recommend for my patients to treat their dry eye disease.
Demulcent
The second group of active ingredients is called demulcent. This is
the main ingredient in artificial tears which determines the consistency and
thickness of the drop. Demulcents are typically mucoprotective
agents. They reduce inflammation and irritation of the mucus membrane
of the eyes and hold moisture to lubricate the surface of the eye.
the main ingredient in artificial tears which determines the consistency and
thickness of the drop. Demulcents are typically mucoprotective
agents. They reduce inflammation and irritation of the mucus membrane
of the eyes and hold moisture to lubricate the surface of the eye.
They act on both the
aqueous and the mucin layers
of the tear film. There are a few common demulcents used by different brands
of artificial tears. Carboxymethyl cellulose sodium (CMC) is the main
demulcent used in the Refresh brand artificial tears made by
Allergan. Systane brand of artificial tears made by Alcon typically
contains polyethylene glycol or propylene glycol as their demulcent.
aqueous and the mucin layers
of the tear film. There are a few common demulcents used by different brands
of artificial tears. Carboxymethyl cellulose sodium (CMC) is the main
demulcent used in the Refresh brand artificial tears made by
Allergan. Systane brand of artificial tears made by Alcon typically
contains polyethylene glycol or propylene glycol as their demulcent.
The other commonly used demulcent agent is hydroxypropyl methylcellulose
(HPMC). It is the demulcent used in GenTeal brand artificial tears
made by Alcon. Variation in the concentration of the demulcent such
as CMC affects the consistency and the viscosity of the artificial
tears.
(HPMC). It is the demulcent used in GenTeal brand artificial tears
made by Alcon. Variation in the concentration of the demulcent such
as CMC affects the consistency and the viscosity of the artificial
tears.
For example, Refresh Optive gel drop contains 1.0% CMC which is
double the concentration of CMC in the regular refresh optive eye drop. This
allows the gel drop to provide a longer-lasting
lubricating effect.
double the concentration of CMC in the regular refresh optive eye drop. This
allows the gel drop to provide a longer-lasting
lubricating effect.
However, the higher concentration of the demulcent used increases the
thickness of the artificial tears. This will require more
blinking action by the eyelid to spread the demulcent polymer over
the surface of the eye. Therefore if you use a gel eye drop you may notice
it takes a little bit longer and more blinks to
clear your vision after you put in the eye drop.
thickness of the artificial tears. This will require more
blinking action by the eyelid to spread the demulcent polymer over
the surface of the eye. Therefore if you use a gel eye drop you may notice
it takes a little bit longer and more blinks to
clear your vision after you put in the eye drop.
Emollient
The third category of active ingredients is emollient. An emollient is
usually fat or oil providing a long-lasting lubricating effect, and
the eye drop which contains emollients tend to be thicker and take
longer to clear up. So the liquid formulations of artificial tears typically
do not contain a large number of emollients.
usually fat or oil providing a long-lasting lubricating effect, and
the eye drop which contains emollients tend to be thicker and take
longer to clear up. So the liquid formulations of artificial tears typically
do not contain a large number of emollients.
For example, mineral oil is a commonly used emollient and is
intended to replace and thicken the lipid layer of the tear film in
order to improve the stability of the tears and slow down the
evaporation of the tears.
intended to replace and thicken the lipid layer of the tear film in
order to improve the stability of the tears and slow down the
evaporation of the tears.
More commonly emollients are found in ointment formulations of artificial
tears such as Refresh PM and Systane Nightime eye ointments. These
formulations are more frequently used before bedtime and reserved for
moderate to severe dry eye disease.
tears such as Refresh PM and Systane Nightime eye ointments. These
formulations are more frequently used before bedtime and reserved for
moderate to severe dry eye disease.
Some newer liquid formulations of artificial tears target all
three layers of the tear film including the lipid layer, which often
contain a small amount of emollient to provide a longer-lasting lubricating
effect to the eye.
three layers of the tear film including the lipid layer, which often
contain a small amount of emollient to provide a longer-lasting lubricating
effect to the eye.
Artificial tears which contain emollients are a little bit thicker. So
after you put in the drop make sure you blink a few times to
spread out the eye drop across the surface of the eye. You may notice
the vision is a little bit blurry and it may take a few blinks to
clear up your vision. If you want to know what eye drops should not use for dry eyes. Click here
after you put in the drop make sure you blink a few times to
spread out the eye drop across the surface of the eye. You may notice
the vision is a little bit blurry and it may take a few blinks to
clear up your vision. If you want to know what eye drops should not use for dry eyes. Click here
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