Why Santen’s Diquas eye drops still matter for dry eyes

Diquas from Santen aims at stubborn dry-eye symptoms that standard artificial tears often fail to calm. What makes the prescription eye drop different, where it helps, and where patients still have to compromise.

Reviewed: ad hoc news Accessory & Components desk. Edited and checked on 2026-06-17, 20:59. Details in the imprint.

With Diquas ophthalmic solution from Santen, the first sensation many patients notice is not marketing promises but a quiet relief when stubborn dry eyes finally feel less scratchy and raw after a day in air-conditioned offices or on screens.

What sets Diquas apart

Diquas is a prescription eye drop that targets dry eye by stimulating the eye’s own tear and mucin production, rather than just coating the surface like classic artificial tears. This approach is designed for patients whose symptoms persist despite regular lubricating drops.

The active ingredient is diquafosol sodium at a 3 percent concentration, formulated as an ophthalmic solution. It works on P2Y2 receptors on the ocular surface, encouraging secretion from conjunctival epithelial and goblet cells, which helps stabilize the tear film.

How it feels in everyday use

In practice, patients describe a clear, slightly viscous drop that spreads quickly across the eye rather than sitting as a thick gel. There is often a short, mild stinging when the drop hits an irritated surface, but this typically fades within seconds.

Because Diquas is used multiple times per day, routine matters. Many users build it into fixed rituals: after waking, at lunch, in the late afternoon. The payoff is a more consistent comfort curve throughout the day, especially in dry office air or heated trains.

Dosing and indications

In Japan, Diquas is approved for the treatment of dry eye and is typically dosed as one drop in each affected eye six times daily, though the exact schedule is determined by the prescribing physician. It is intended for chronic use, not a one-off rescue treatment.

The product is particularly relevant for patients with aqueous-deficient dry eye or instability of the mucin layer, where simple hyaluronic acid drops often fail to deliver lasting relief. Ophthalmologists in Asia frequently prescribe it when first-line lubricants prove insufficient.

Strengths and trade-offs

The big advantage of Diquas is that it tackles the disease mechanism more actively by promoting secretion at the ocular surface, which can improve both objective tear film parameters and subjective symptoms. Clinical studies in Japan have reported improvements in fluorescein staining scores and patient-reported dryness.

The downside is the frequency of instillation and the prescription-only status. Six times per day is a demanding schedule, especially for people in jobs where taking regular breaks is difficult. Some patients also report transient blurred vision immediately after instillation, which makes fine work briefly awkward.

Where it is available

Diquas is marketed primarily in Japan and selected Asian markets, often under the Santen brand name combined with the diquafosol sodium description. It is not broadly available as a standard prescribed dry-eye therapy in Europe, and German patients usually encounter alternative products instead.

In its home market, the eye drop is dispensed via ophthalmologists and pharmacies, with reimbursement depending on local insurance rules. For many patients there, Diquas has become a quiet workhorse against chronically irritated eyes, especially in urban environments with strong air conditioning and screen-heavy workdays.

Company context and stock reference

Santen has long positioned itself as a pure-play ophthalmology specialist, with a portfolio ranging from glaucoma drops to dry-eye treatments like Diquas and surgical products for cataract procedures. The company is also investing in new formulations and combination therapies around ocular surface disease.

Shares of Santen Pharmaceutical (JP3512800005) trade on the Tokyo Stock Exchange in Japanese yen.

Key facts on Diquas

• Product: Diquas ophthalmic solution 3%
• Manufacturer: Santen Pharmaceutical Co., Ltd.
• Category: Accessory/Spare part - ophthalmic prescription drop
• Launch: Initially approved and launched in Japan in the early 2010s
• RRP / Price: Determined by local reimbursement and pharmacy pricing in Japan
• Availability: Prescription-only in Japan and selected Asian markets via ophthalmologists and pharmacies
• Target group: Patients with dry eye, especially those insufficiently controlled with standard artificial tears
• Highlight / USP: Stimulates tear and mucin secretion via P2Y2 receptor activation rather than acting only as an external lubricant

This article was AI-assisted and editorially reviewed. Product information without guarantee; prices and availability may change at short notice. No investment advice, no buy or sell recommendation. Stock-market transactions involve risks up to total loss.