Dry eye disease occur when there is a disruption in the tear film quantity or quality. Tears normally keeps the eye moist and lubricated. The water component of tears are produced by a single water producing gland called the lacrimal gland located underneath the upper eye bank. Multiple oil producing glands located in the eyelids, called the meibomian glands are responsible for secretion of the lipid layer of the tear film. Goblet cells in the conjunctiva secretes the inner mucin layer of the tear film.

Tears are spread over the surface of your eye when you blink. In DED tear glands produce too little tears or tears of poor quality. Without an adequate tear film covering the surface of the eye, spots on the front window of your eye (cornea) dries out and symptoms arise. Patients suffering from DED usually have irritation of the eyes, a gritty or burning feeling. The eyes may be red and there is often crusting on the eyelids. Another common symptoms in DED is teary eyes. This is usually due to a specific type of DED called evaporative DED. In these patients the water layer of the tearfilm is sufficient. The deficit arise from decreased functioning of the oil glands in the lids, leading to a poor outer lipid layer in the tearfilm.

A very common contributing condition in patients suffering from dry eyes is Blepharitis. Blepharitis is chronic inflammation of the eyelid. This affects the eyelashes and the glands that produce tears. If left untreated it may lead to dry eyes, styes as well as meibomian cysts.

There are many factors that often contribute to dry eyes. DED is a very common disease, especially affecting older people. The most common risk factors include:

• Contact lens wear
• Post-menopausal females
• Environmental factors : wind exposure, smoking, low humidity, high room temperatures.
• Diet lacking in Omega 3 and 6 fatty acids
• Associated medical conditions : Diabetes, Sjogren’s disease, auto-immune diseases, HIV
• Associated medication use : Antihistamines, chemotherapy, antidepressants, beta-blockers
• Associated ocular conditions : Glaucoma, prior refractive surgery, blepharitis, pterygium/pinguecula

The diagnosis of dry eyes is made by doing a thorough history and clinical examination. Specific important factors we enquire about during history taking include:

• Enviromental questioning : smoke, air conditioning, wind, exacerbating conditions
• Co-existing eye diseases : glaucoma, allergies, contact lens wear
• Medical history
• Previous eye surgery or trauma

We will examine your eyes with a microscope and use special eye drops and dyes. This helps us to evaluate the quality and quantity of your tear film. We measure the time it takes for a tear to start evaporation (Tear break up time – TBUT). Measuring the height of your tear meniscus helps us to determine the quantity of tears and the function of the tear drainage syste. We do a full eye examination to look for contributing factors like blepharitis, rosacea, meibomian gland dysfunction.

It is very important to realise that dry eyes can be treated, but rarely cured. In most cases treatment will be lifelong. In cases where treatment is discontinued, we know from experience that symptoms restart and the cycle of irritated, burning, teary eyes restarts. Treatment is approached in a step-wise fashion. Addressing the underlying cause is essential..

Step 1 : Education and lifestyle modifications. Dietary supplementation of essential fatty acid (Omega 3). Eyelid hygiene and warm compresses are advised. Tear supplement drops are initiated. There are many different options on the market. We evaluate each patient individually and based on the specific type of dry eyes and patient specific factors, we make recommendation on an individualised basis.

Step 2 : A preservative free lubricating drop is a very good alternative for most patients. The benefit to using preservative free drops is less toxicity caused by the preservatives routine used in the traditional eye drops. If drops are not sufficient we then recommend thicker drops, then gel, then ointment. Tea tree containing eyelid scrubs are beneficial in patients with Demodex blefharitis, Moisture chamber spectacles are recommend. Punctal plug can be placed in the ducts draining tears away from the eye. This will preserve tears on the ocular surface. Topical antibiotic/steroid drops may be indicated in certain cases for short term management of blepharitis. Oral antibiotic are indicated in specific cases with severe blepharitis.

Step 3 : Autologous/allogeneic serum is a specific drop manufactured from your own blood/placental stem cells. It contains all the nutrients and growth factors needed for a healthy ocular surface. Oral medication to increase tear secretion can also be considered. Certain topical treatment like Cyclosporin or Tacrolimus is indicated in some patients.

Step 4 : Surgical options to treat dry eyes include permanent punctal occlusion. To limit exposure and decrease evaporation a surgical approach called a tarsorraphy can be performed. This involves closing the eyelids on the outer part of the lid surgically.

Self-test for dry eye disease

If you experience any eye symptoms that concerns you it is a good idea to come for a cinical examinaionm. There are questionnaires available to help diagnose dry eyes. The SPEED questionnaire developed by Ngo, Situ, Keir, Korb, Blackie, & Simpson is useful and can aid with diagnosing the condition and severity.