Fact in a Blink
- During a normal resting period: 17 blinks/min
- While using a computer: 7 blinks/min
- While reading: 4 or 5 blinks/min
- During a conversation: 26 blinks/min
Tears, the mediators of emotions, are also important for ensuring the health and safety of eyes. Tears are composed of salts, enzymes, and other proteins, as well as lipids and metabolites. Apart from keeping the eyes moist, tears help to wash away dust and foreign bodies from the eyes. Tears are formed in the lacrimal glands, located above the eye, but inside the eye orbit. Also, a ducting system is present in the inner corner of our eyes, which serves to drain the excess tears into the nose. The proper functioning of this lacrimal apparatus ensures the wellness of eyes. The quantity and quality of tears, when affected, results in dryness and gives rise to a scratching sensation in the eye. The other symptoms which are normally seen with dry eyes are burning, itching, sensitivity to light, pain, redness, and blurry vision.
Whenever you blink, a tear film is formed over each eye. The tear film is made up of three layers. The innermost layer is the mucin or mucus layer which coats the cornea and provides a base for the other two layers. This layer is formed from the mucous secretions of specialized cells, called goblet cells, located in the eye. The next layer is known as the aqueous layer and is secreted by the lacrimal glands. This layer is involved in keeping the eye moist, and as also in the supply of oxygen and nutrients to the eye. It contains molecules with antibacterial activities, and thus protects the eye from bacterial infections. The outermost layer is called the lipid or oily layer. It coats the underlying aqueous layer, and prevents evaporation of this layer. The disruption of these films results in dry and gritty eyes. The tear film must remain continuous between the two blinks to ensure a healthy eye.
Dryness, and a scratchy and gritty feeling in eyes can be due to a variety of reasons ranging from lifestyle changes to severe disorders. These have been summarized below.
- Age: The production of tears decreases with advancement in age. Women are more prone to this, especially after menopause, or under conditions of hormonal imbalances.
- Environment and Lifestyle Changes: Smoke and exhaust from industries and vehicles, as well as particulate pollutants present in air, result in irritation and dryness in eyes. Coupled with this, is the increased addiction to television, constant use of computers and laptops, and other eye-straining activities. Stress-related conditions like insomnia further add to this. As a consequence, the frequency with which you blink reduces, affecting the tear formation process and frequent disruption of tear film.
- Use of Contact Lens: Use of inappropriate contact lenses or their prolonged use may result in irritated eyes, and lead to eye infections.
- Medications: The use of various medicines might result in dryness in the eyes, and affect tear formation, or alter tear composition. These include antihistamines and other anti-allergy medicines, nasal decongestants, blood pressure medicines, and certain medicines used in the treatment of Parkinson's disease. Birth control pills - leading to changes in hormone levels - may alter tear composition. Excess intake of vitamin supplements is also associated with dryness of eyes.
- Medical Conditions: Different medical conditions, like skin allergies around the eye, and eye infections can lead to scratchy eyes. Conjunctivitis or pink eye, and diseases affecting the glands involved in tear formation and secretion give rise to dryness. People suffering from rheumatoid arthritis also experience symptoms of dryness in eyes. Autoimmune diseases like Graves' disease andSjögren's syndrome are characterized by inflammation of tear glands and dryness of eyes.
- Eye Surgeries: Cosmetic surgeries pertaining to eyes can lead to complications involving dry eyes. Scratchy sensation in eyes after LASIK (Laser-assisted in-situ keratomileusis) surgery for vision correction is a common observation.
- Dry Eye Syndrome: In some cases, it has been seen that dry eyes causes excess watering, as a response to the constant irritation. Such overproduction of tears, however, does not help the cause, since the tears so produced do not have lubricating qualities. If this condition is not treated at the earliest, it can give rise to several other problems, like severe eye damage, vision loss, etc.
- Redness in Eyes: Redness is caused due to many factors including enlarged blood vessels or hemorrhage on the surface of the eye. Some of the eye diseases which can cause this condition are pink eye, subconjunctival hemorrhage, pterygium, and pinguecula (non-cancerous growth in the eye).
The first step in reducing the severity would be to follow a healthy lifestyle. Use of appropriate eyewear while using laptops or computers, as also while traveling can reduce the stress on eyes. In order to start a treatment, it is crucial to determine the exact cause of dryness, and then choose the appropriate treatment method. The various options available have been listed below.
- Lubricating ointments and eye drops can be used for temporary relief. Artificial tears are a type of lubricant eye drops that specifically help alleviate symptoms associated with dryness in eyes. They are also used to prevent dryness due to prolonged use of contact lenses.
- Eye drops containing cyclosporine are very effective against dry eyes as per a study conducted in 2010 and published in the Korean Journal of Ophthalmology.
- Over-the-counter eye wash solutions, containing mild cleansing agents, can be used to help get rid of allergens and irritants.
- Use of warm compresses once or twice a day helps to get relief from the scratchy sensation.
- Lacrimal or punctal plugs can be inserted into the tear ducts, in order to block tears from draining into the nose. Such plugs help to retain tears in the eyes for a longer time, and thus help to tackle the dryness. Plugs have to be inserted in the right positions in the eyes using a special 'inserter' available with the plugs. These plugs can be silicon-based, or in form of substances that take the form of soft gels on insertion into the duct. They can be permanently placed or used temporarily, depending on the seriousness of the case.
- Permanent blockage of the tear-draining ducts by surgery may be used as the last resort.
This quote by Christian Nevell Bovee, an American author and lawyer, seems so true and valid. Eyes are the most expressive organs of our body, and require utmost care and attention. So, now that we know the hidden biological story behind our tearful eyes, let us make a conscious effort to enhance their expression and beauty.
Disclaimer: This HealthHearty article is for informative purposes only, and should not be used as a replacement for expert medical advice.