What is Dry Eye?
Dry eye Syndrome is a very common condition that affects more than 2 million people in the UK. Its incidence increases with age, and it affects more women than men. Dry eye occurs when people don't have either enough tears, or the proper composition of tears.
The tear film is composed of three layers, which are co-dependent on each other for proper function. The outermost oily layer of the tear film is produced by the meibomian glands (in the eyelids), and helps reduce evaporation of the tears. The middle, watery layer is made by the lacrimal gland and washes away irritants. The inner, mucus layer is secreted by the goblet cells in the conjunctiva (mucous lining) of the eye and helps the tear film stick to the cornea.
Blepharitis
Blepharitis is a condition that affects the eyelid margins. It may also affect the tissues lining the lids and eyeball (the conjunctiva) and the window of the eye (the cornea). There are several different types of blepharitis, which may occur alone or in combination; these types involve either the lash bearing area (anterior blepharitis) or the area behind the lashes where the meibomian glands open (posterior blepharitis or meibomian gland dysfunction).
Blepharitis is an extremely common cause of dry eye in people over 40, although it can develop at any age and children suffer with it too. The symptoms of blepharitis can include:
- Burning, soreness or grittiness in the eyes
- Crusty eyelashes, sticky / watery eyes
- Red / itchy eyelids
Blepharitis can be caused by a bacterial infection, or it can be a complication of a skin condition such as:
- Seborrhoeic dermatitis, which causes an itchy rash on the skin and scalp (seborrhoeic dermatitis of the scalp is called dandruff)
- Rosacea, which causes the face to appear red and blotchy
Dry Eye Drops
There are many Dry Eye medications on the market, especially different forms of eye drops and ointments. Restasis is the only FDA approved eye drop for DED (dry eye disease) which has been proven to work in chronic inflammatory dry eyes.
There are many different products available over-the-counter, or on prescription only. Although most artificial tears contain similar ingredients, they differ in the type of lubricant used, in their chemical properties, and in the type (or lack thereof) of preservatives used. These are broadly classed under the following categories.
HMC-Based Artificial Tears
HMC-based artificial tears work on the simple principle of lubricating the ocular surface in order to promote the integrity of the surface, but do not have viscosity-increasing properties. Several brands of artificial tears:
- Tears Naturale / Genteal (Alcon), contains hypromellose and a gentle preservative (polyquad in Tears Naturale).
- Hypromellose (multiple pharma companies) contains hypromellose & generally the preservative is benzalkonium chloride, which can destabilise the tear film.
- Artelac (Bausch & Lomb) 0.32% hypromellose.
- Bion Tears (Alcon), contain hypromellose, dextran, zinc & bicarbonate and are only available on prescription. They are more beneficial in relieving dryness and irritation caused by Sjögren's.
- Ilube (Moorfields Pharmaceuticals) contains 5% acetylcysteine & hypromellose, both these ingredients work together for DED due to abnormal mucus production.
- Tear-Lac (Scope Ophthalmics) contains 0.3% hypromellose, preservative free.
CMC-Based Artificial Tears
Carboxymethylcellulose (CMC) is a polysaccharide known as mucilage. They increase the residence time of tears as well as increase the viscosity of tears. Commonly available CMC artificial tears include:
- Optive / Celluvisc / Refresh (Allergan) - contain CMC & provide osmoprotection against high osmolarity of the tear film in DED.
- TheraTears (Advanced Vision Research) eye drops and liquid gel contain carboxymethylcellulose and provide a tear-matched electrolyte balanced solution for dry eyes.
Propylene Glycol Based Artificial Tears
- Systane / Systane Ultra (Alcon) contains polyethylene glycol & HP guar. The HP guar in this artificial tear brand is gel-forming and offers unique properties that improve recovery of the ocular surface due to possible increased retention of the artificial tear drop, and increase in tear film break up time.
- Systane Balance (Alcon) may be helpful in patients with conditions causing evaporative dry eye (e.g., meibomian gland disease).
- Blink Tears (Abbott Medical Optics) contains polyethylene glycol and hyaluronate with an "ocupure" preservative, and is clinically shown to improve tear film stability.
SH-Based Artificial Tears
Recent studies have shown that sodium hyaluronate eye drops are useful in improving subjective symptoms (as well as the ocular health) of dry eye patients, treating lipid tear-deficient patients and managing Sjögren's syndrome patients. Sodium hyaluronate also seems to have protective effects on the corneal epithelium and may be useful in a wide variety of patients with dry eye.
- Hylo-Tears / Hylo-Forte (Scope Ophthalmics): preservative free 0.1% / 0.2% hyaluronate.
- Artelac Rebalance (Bausch & Lomb) contains 0.15% hyaluronate, Vit B12, mineral nutrients & an innovative preservative Oxyd.
- Clinitas Soothe (Altacor) 0.4% hyaluronate, preservative free.
- Lubristil (Moorfields Pharmaceuticals) contains 0.15% hyaluronate, preservative free.
PVA-Based Artificial Tears
Polyvinyl alcohol lubricates the ocular surface.
- Clinitas Ultra (Altacor) contains PVA & povidone with a mild preservative.
- Murine Tears (Murine Eye Care) contains PVA, povidone & six of the 11 major ingredients found in natural tears.
Oil-Based Tears
Castor/soya bean oil aids in the reformation of the lipid layer of the tear film and prevents evaporation of the existing tear film. Oil-based eye drops are used in the treatment of meibomian gland disease.
- Optive Plus (Allergan) contains castor oil.
- Emustil (Moorfields Pharmaceutical) is made from 7% soybean oil and 3% natural phospholipids.
Anti-Inflammatory Drops
Restasis (Allergan) - This is the only FDA approved medication for Dry Eye Syndrome. Recommended dose is 1 drop twice a day. It's important to note that this medicine is not intended for instant relief, but rather a long-term medication that doesn't have the side effects of steroid-based eye drops.
Steroid-Based Drops
It's important to know that long-term use of steroid eye drops can cause a rise in eye pressure and development of a cataract. None of the eye drops listed below should be taken without the consent of your eye care professional. They are Alrex, Lotemax, FML and Vexol.


















