Tear Stimulants and Tear Substitutes for Dogs in Canada: How They Differ
Publishing on Friday, August 21, 2026
Dry eye in dogs, known clinically as keratoconjunctivitis sicca (KCS), is a diagnosed medical condition, and the products used for it fall into two very different groups. Tear stimulants — cyclosporine (sold in Canada as Optimmune) and tacrolimus — actually increase tear production, and they are prescription-only veterinary drugs in Canada that require a veterinary examination and an ongoing prescription. Tear substitutes, by contrast, are over-the-counter lubricants such as I-Drop Vet Plus and other hyaluronan or carboxymethylcellulose drops; they replace moisture and ease discomfort, but they do not treat the underlying cause and cannot restore tear production. Understanding which group a product belongs to matters, because reaching for a lubricant when a dog actually needs prescription therapy can allow corneal damage to progress. If your dog is squinting, producing thick discharge, or has a dull or cloudy-looking eye, that warrants a veterinary appointment rather than a purchase.
Top Picks Summary
Optimmune Ophthalmic Ointment
Optimmune is a prescription cyclosporine ophthalmic ointment that stands out as the tear-stimulant option on this list because it addresses underlying immune-mediated lacrimal dysfunction rather than only replacing tears. For canine keratoconjunctivitis sicca (KCS) it is often costlier up front than over-the-counter lubricants here, but its disease-modifying effect can reduce long‑term medication needs and visits compared with purely palliative drops or gels.
$50 – $90
I-Drop Vet Plus Lubricating Eye Drops
I-Drop Vet Plus is a veterinary-formulated lubricating drop with 0.25% viscoadaptive hyaluronan designed for frequent use in dogs; its 10 mL multi-dose bottle uses a sterile one-way valve that dispenses a single dosed drop per blink, making it a strong economical choice for chronic, high-frequency dosing. Compared with Optimmune it does not stimulate tear production but offers a low-cost option for ongoing lubrication.
Remend Lubricating Eye Drops
Remend provides a thicker, longer-retaining lubricating formulation intended to bridge the performance gap between drops and ointments, offering extended surface protection for dogs with moderate tear deficiency. Technically it delivers longer contact time than standard aqueous drops like I-Drop Vet Plus and is a lower-cost alternative to prescription immunomodulators like Optimmune for symptomatic management.
Systane Ultra Lubricant Eye Drops
Systane Ultra uses a proprietary polymer technology to create a longer-lasting tear film substitute that is widely available and backed by large-scale clinical use; this makes it a market-leader in retention time among drops and a practical choice when improved comfort and lower dosing frequency are desired. While not veterinary‑specific like I-Drop Vet Plus, its advanced formulation often provides superior symptomatic relief compared with basic aqueous lubricants and at a mid-range price point versus prescription agents.
Viscotears Liquid Gel
Viscotears Liquid Gel is a high-viscosity, gel-forming product intended for sustained lubrication and is particularly useful for nighttime or severe dry-eye episodes in dogs, offering the longest residence time of the non-prescription options. Financially it is attractive for pet owners needing intermittent but powerful relief because a small dose achieves prolonged effect, though it does not stimulate tear production like Optimmune and can be blurring immediately after application compared with thinner drops.
$18 – $30
Tear substitutes are judged mainly on how long they stay on the eye, how comfortable they are for repeated daily use, and whether they are preservative-free for long-term use. Those qualities affect comfort and convenience; they do not make a lubricant a replacement for prescription therapy, and they are not a basis for self-treating a dog whose eye condition has not been examined.
Tear Stimulants Versus Tear Substitutes: What Sets Them Apart
A dry-eye diagnosis and prescription tear stimulants require a veterinarian; over-the-counter lubricants only manage symptoms. Veterinarians diagnose KCS using the Schirmer tear test and assess corneal health with fluorescein staining, and those steps cannot be replicated at home. The notes below outline how the two product groups differ in what they do and how they are obtained; they are general background, not treatment guidance, and none of it replaces an examination.
Tear stimulants act on the immune-mediated cause of KCS to increase the dog's own tear production. Cyclosporine ophthalmic ointment is authorised in Canada as a prescription veterinary drug (Optimmune, DIN 02142155, Intervet Canada Corp) and cannot be bought without a veterinary prescription.
Tacrolimus is sometimes used for dogs that respond poorly to cyclosporine. It is not an over-the-counter option and is dispensed and monitored by a veterinarian.
Tear substitutes are lubricants. Hyaluronan-based drops such as I-Drop Vet Plus stay on the ocular surface longer than water-thin drops, which is why they are dosed less often, but they add moisture rather than restoring tear production.
Carboxymethylcellulose formulations are another lubricant class; the choice between hyaluronan and CMC is largely about viscosity and the individual dog's comfort.
Preservative-free preparations are generally preferred when drops are used many times a day over long periods, since preservatives can irritate an already compromised ocular surface.
Where a dog needs both a prescription stimulant and a lubricant, that combination is set by the treating veterinarian, who also decides the dosing interval and the recheck schedule.
Human artificial-tear products are formulated and labelled for people. Some appear alongside veterinary products in listings, but whether any of them is appropriate for a specific dog is a question for a veterinarian, not an assumption to make from a product page.
Frequently Asked Questions
Which dog should use Optimmune Ophthalmic Ointment for KCS?
Optimmune Ophthalmic Ointment is a prescription cyclosporine ophthalmic ointment shown to stimulate tear production in dogs with keratoconjunctivitis sicca (KCS); it’s typically used for immune-mediated lacrimal dysfunction and monitored for long-term immunomodulatory therapy, with a 4.4 rating.
What spec makes I-Drop Vet Plus different for frequent dosing?
I-Drop Vet Plus is a sterile ophthalmic lubricant formulated for animals with 0.25% viscoadaptive hyaluronan, delivered from a 10 mL multi-dose bottle whose one-way valve dispenses a single sterile drop per blink for reliable frequent dosing; it has a 4.4 average rating.
Is Remend Lubricating Eye Drops worth the price versus I-Drop?
Remend Lubricating Eye Drops price isn’t provided, but I-Drop Vet Plus costs CA$28.07; I-Drop delivers 0.25% hyaluronan from a valved multi-dose bottle for frequent use, while Remend is a thicker, longer-retaining lubricating drop for extended surface protection.
Can Remend Lubricating Eye Drops be used with other vet treatments?
Remend Lubricating Eye Drops is described as compatible with common veterinary treatments and suitable for daily maintenance use as advised by a vet; it supports reduced friction and promotes a more stable tear film, with a 4.0 average rating.
Conclusion
The practical takeaway is that these two groups are not interchangeable and this page is not a substitute for a diagnosis. If a veterinarian has already confirmed KCS and prescribed a tear stimulant, that prescription is filled through your veterinarian or a licensed pharmacy, not chosen from a shortlist. If your dog's eyes simply look dry or irritated and nothing has been diagnosed, the right first step is an examination, because several conditions that look alike on the surface are treated very differently. Over-the-counter lubricants have a genuine role in keeping an eye comfortable, but only alongside veterinary care rather than in place of it.