Dry eye syndrome is a common cause of eye irritation. Tears reduce the risk of eye infection and, with each blink of the eyelids, help clear the eyes of any debris. Dry eyes caused by decreased production of fluids from tear glands can prevent tears from performing their useful functions and affect vision.

An imbalance in the substances that make up tears also can make eyes become dry. Common steps to deal with dry eyes include using artificial tears and taking steps to prevent dry eyes in the first place

Signs and symptoms

Signs and symptoms of dry eyes may include:

• A sense of a foreign substance in your eyes.
• Stringy mucus in or around your eyes.
• Difficulty wearing contact lenses.
• Increased eye irritation from smoke or wind.
• A stinging, burning or scratchy sensation in eyes.
• Eye fatigue after short periods of reading.
• Both eyes affected usually at once.

Causes

Tears are much more than water. They are a complex mixture of water, fatty oils, proteins, electrolytes, bacteria-fighting substances and growth factors those regulate various cell processes. This mixture helps the surface of eyes smooth and clear.

For some people, the cause of dry eyes is an imbalance in the composition of tears. Others don't produce enough tears to keep eyes comfortably lubricated. Medications and other causes, such as environmental factors, also may lead to dry eyes.

Poor tear quality

Eyelids spread tears across the surface of eyes in a continuous thin film. The tear film has three basic layers:

• Oil.
• Water.
• Mucus

Problems with any of these layers can cause dry eye symptoms.

Oil.

The outer layer, produced by small glands on the edge of the eyelids (meibomian glands), contains fatty oils called lipids. These lipids smooth the tear surface and slow evaporation of the middle watery layer. When the oil layer is abnormal, the watery layer evaporates at too fast rate. Dry eye symptoms are common in patients whose meibomian glands are clogged. Meibomian dysfunction is more common in people with inflammation of eyelid margins (blepharitis) and other skin disorders.

Water.

The middle layer, which makes up about 90 percent of tears, is mostly water with a little bit of salt. This layer, produced by the tear glands (lacrimal glands), cleans eyes and washes away foreign particles or irritants. If eye produces only small amounts of water, the oil and mucus layers can touch and cause the stringy discharge familiar to patients with dry eyes.

Mucus.

The inner layer of mucus allows tears to spread evenly over the surface of eyes.

Decreased tear production:    
Like skin and hair, tear production tends to dry up as one get older. Insufficient tear production ultimately leads to irritation. Although dry eyes can affect both men and women at any age, the condition is more common among women, especially after menopause. This may be due to hormonal changes. Damage to the tear glands from inflammation or radiation can hamper tear production.

Medications that may cause dry eyes

It is found by recent researches that common medications can cause dry eyes those include:

Diuretics, drugs commonly used to treat high blood pressure, antihistamines, decongestants, and sleeping pills etc.

Other causes of dry eyes

Problems unrelated to tear production or tear quality also may cause eyes to feel dry and scratchy. These include:

• Inflammation of the eyelid margins.
• Condition in which the eyelid turns inward.
• Condition in which the eyelid sags away from the eyeball.
• Environmental irritants such as smoke, sun, wind, low humidity, high altitudes and indoor heating.
• Disruption of blink reflex.
• An allergic reaction to eye drops or ointments.
• Prolonged time between blinking, such as visually concentrating on something, for example, working at a computer, driving or reading.

Treatment

The underlying cause of dry eyes may be an inflammation both in the lacrimal glands and on the surface of the eyes. When the eye is quite irritated from dryness, it can over stimulate the nerve fibers that travel from the eye to the lacrimal gland. That over stimulation causes lacrimal gland inflammation, which in turn reduces tear formation even further.

Ayurveda has suggested the eye care by specific therapies. Those are called as kriya kalpas. In dry eye syndrome and its related aliments vata dosha is considered as prime factor. Therefore dryness is attained to the eye. Treatment  must be strictly aimed to arrest the vitiated vata dosha in/on the eye. It is found and established that in excessive dryness of eye tarpana is the most reliable treatment. Leading and frontline ghrita compound generally used in tarpana is Triphala ghrita.

Do?s and Don?ts:

• Remember to blink.
• Avoid air blowing into the eyes.
• Avoid rubbing eyes.
• Wear glasses on windy days and goggles while swimming.