Thera tears vs Systane – Which Solution for Runaway Tears?

With so many eye drop brands out there, how does one decide which one to select? Let’s undertake this Thera tears vs Systane quest to eliminate any guess work – at least from the 2 brands!

I never imagined I would have to deal with dry eyes, but here I am. What started like simple itching, the kind you get when a foreign particle gets into your eyes, has progressively developed into watery, stinging eyes. I take hours falling asleep because I have to endure the ‘sand-in-the-eyes’ feeling. I found some answers online. I mean, at least I know I am dealing with dry eyes. So,my solution is just an eye-drop decision away. If only I knew what brand to settle for! I hope a Thera tears vs Systane comparison will help me.

What are the differences between Thera tears and Systane? How do they compare?

Comparison Chart of Thera tears and Systane

Eye drop
Thera tears
Available in 15ml and 30ml in convenient multi-use bottles
Availalble in 30ml multi-use bottle and vials for the non-preservative solution
Preservative-free in the eye
Both with preservatives and preservative free
Active Ingredient
Carboxymethylcellulose (CMC) – Changes tear composition
Polyethylene glycol and propylene glycol – Lubricants
Non-active ingredient unique to the eye drop
Dequest, sodium bicarbonate, sodium perborate, sodium phosphate
hydroxypropyl guar (HP guar)- forms protective coat, polyquaternium-1 (preservative), It may also contain hydrochloric acid and sodium hydroxide(pH balancer)
Is a hypotonic solution
Not hypotonic
Lubricant that brings relief for dry eye symptoms, including exposure to the wind and sun. It’s also a protectant against continued irritation of the eye.
Lubricant relieving irritation, burning and other dry eye discomforts.


Thera tears is packed in 15ml and 30ml multi-use bottles. Systane (preserved) comes in a 30ml multi-usable bottle, too. The non preserved solution comes in small vials that carry about 4 drops of solution. For this reason, the vial is a single-dose unit (SDU). It has to be disposed of after a single use. One pack has 30 sterile vials.


Thera tears has a special vanishing preservative which turns into oxygen and water upon contact with the tear film. This is safer than the common preservatives used in many eye drops.

Systane comes in both non-preserved and preserved forms. The preservative in the preserved Systane is Polyquaternium-1. Much as eye drops with preservatives are becoming increasingly unpopular, they are beneficial in that they are effective against pathogens, so they keep both the solution and the bottle safe for long. Eye drops without preservatives cannot keep safe for long. Preservative free Systane comes in small vials that hold enough solution for just one dose, and a little more in case of spillage.


The active ingredient in Thera tears is Sodium carboxymethylcellulose. It lubricates the eye by sticking to the eye cells and mimicking the natural tear makeup. In this way it is retained by the cells. For Systane, the active ingredients Polyethylene glycol (PEG) and propylene glycol , lubricate the eye by forming a protective layer over the eye’s mucous membrane. This relieves inflammation and irritation.

The non-active ingredients in Thera tears are important in addressing osmolarity (concentration or saltiness) of the tears. They also ensure the solution is hypotonic (having low osmotic pressure). The most notable non-active ingredient in Systane is hydroxypropyl guar (HP guar) which stabilizes the tear film by increasing its thickness (viscosity).

How Thera tears Extra and Systane Compare – A Quick Review

Thera tears

TheraTears Eye Drops for Dry Eyes, Dry Eye Therapy Lubricant Eyedrops, Provides Long Lasting Relief, 30 mL, 1 Fl oz Value Size

Thera tears is reputed to be the dry eye therapy for immediate and long lasting relief. The natural tear has three layers: An outer oily layer for preventing tears from spilling or evaporating; a middle layer for helping in transportation of nutrients to the cornea; and an inner mucous layer for assisting the tear to ‘stick’ to the eye and keep it moist. In dry eye syndrome, one or more of these layers is compromised, so the available tears are not able to lubricate and nourish the eye. Thera tears intervenes by increasing viscosity to minimize evaporation, ‘sticking’ and retaining moisture to the cornea, and the rest of the eye. Moreover, its hypotonic nature counters high salty/concentration, which is detrimental to the eye.

Besides, it comes in more than one size which gives the consumer control over which size to purchase. The multi-use bottle is convenient but very easily contaminated if the tip comes into contact with any surface.


  • Consumer can make choice on bottle size
  • Hypotonic property prevent eye damage from high salt concentrations
  • Vanishing preservative safe and cheaper than preservative-free


  • The multi-use bottle can be easily contaminated.
  • A vanishing preservative is not as safety guaranteed as a no-preservative solution


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Systane Long Lasting Lubricant Eye Drops Vials Eye Drops, 30 Count, 0.7-mL Each

Systane is supposedly the number 1 doctor recommended brand of artificial tears. It boasts of long lasting soothing comfort, dry eye therapy. Because it comes in both the preserved and the preservative free forms, it is able to meet the needs for both consumers mild symptoms to those who are sensitive or have very severe forms of the dry eye syndrome. In fact, it is comforting to know that the preservative used, Polyquaternium-1, does not have the severe effects of benzalkonium chloride (BAK). Studies have proved that BAK is toxic to the cornea, in some patients.

Systane’s coating property is almost threefold – by the 2 active ingredients, and by HP guar. It ends up forming a protective coat that not only reduces evaporation of tears from the eyes, but also gives the coated cells an opportunity to heal. Though Systane doesn’t have components that address osmolarity, HP guar becomes gel-like when the pH is above 7, preventing damage to the eye cells. Systane is beneficial for patients with evaporative dry eye conditions (e.g. meibomian gland disease).


  • The HP guar protects damaged cells and reduces tear evaporation
  • The Preserved solution is cheaper
  • The preservative free solution is safe for patients with severe dry eye syndrome or those who are hypersensitive to preservatives.


  • The big bottle discourages buying for trial
  • No-preservative formulation may make product costly
  • The vials may be cumbersome


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It is amazing that whereas both eye drops are lubricants, their actions are quite different. One’s dry eyes condition – symptoms, sensitivity to preservatives and severity of the condition, ultimately determine the eye drop of choice. In fact, for severe dry eyes conditions, a doctor’s advice should be sought. All the same, I believe the just concluding Thera tears vs Systane discussion still places the power of decision in your hands.


What is the preservative in Systane products?

Polyquaternium-1. It does not have the severe effects found in benzalkonium chloride (BAK)

Does Systane help red eyes?

Systane Red Eyes is specially formulated to bring relief for red congested eyes.

Can systane eye drops cause headaches?

Headaches are not listed as one of Systane’s side effects. It is always good to discontinue use and consult your doctor when in doubt.

Can I refrigerate eye drop vials?

No the recommended storage temperature is 59 – 86 degrees F (15 -30 degrees C)

Can you use Systane after cataract surgery?

Studies have proved that systane prevents the signs and symptoms of insufficiency of the tear film, decrease post surgery complications and improves repair of the epithelium.


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