Dry Eye Syndrome: A Review
Correspondence Address :
DR. MOHNISH GOPAL.
Dry eye syndrome is a recent discovery in the group of distinct treatable ocular diseases. This condition has been observed to be increasing wildly in the recent past due to civilizational changes. Dry eye is also referred to as tear film instability, a condition that typically develops from deficiencies of one or more components of the biologically complex pre-ocular tear film. Tears are composed of three layers: the outer oily, lipid layer, the middle watery, lacrimal layer, and the inner mucous or mucin layer. Each layer is produced by a different part of the eye for example, the lacrimal gland produces the lacrimal layer. Therefore, a problem originating in any part of the eye can result in dry eyes. Clinically, dry eye cases represent a mixed picture of an allergy, an infection, and either drug or chemical toxicity. Therefore, dry eyes are often considered to be an accompaniment of Spring Catarrh, Follicular/ Trachomatous conjunctivitis, Glaucoma, Aphakia, and so on in clinical practice. Dry eye conditions are classified into those with adequate aqueous tear production and those with aqueous tear deficiency. Lacrimal gland tear production can be determined clinically by means of a Schirmer test without anaesthesia (Schirmer 1) or by other more sophisticated tests for the evaluation of aqueous tear production and turnover. Certain specific pathological tests can differentially diagnose cases with aqueous tear production and aqueous tear deficiency. The market availability of artificial tear solutions or ocular surface wetting/lubricating eye drops have played a significant role in the management of dry eye.
Dry eye syndrome, Tear film, Sjogrenâ€™s syndrome, Aqueous tear production, Aqueous tear deficiency, Schirmer test, Meibomian gland,
An ocular surface disease results from a multi-factorial, heterogeneous disorder of the pre-ocular tear film. This disorder of the tear film is also termed dry eye. There are numerous disturbing factors that disrupt the equilibrium of the complex and stable system formed by the tear film and the ocular surface (1). Dry eye, either alone or in combination with other conditions, is a frequent cause of eye irritation that leads patients to seek ophthalmologic care (2).
The disease is usually not curable and may cause frustration to both patients and physicians although its symptoms often improve with treatment. Visual morbidity may cause dry eye and may compromise the results of corneal surgery.
The dry eye syndrome varies in severity, duration, and aetiology (3). It has several causes. It occurs especially during menopause as a part of the natural aging process and as a side effect of systemic medications, such as antihistamines, antidepressants, medications for blood pressure and Parkinson's disease , and birth control pills. These medications decrease tear production and may lead to an increase in the severity of the symptoms. A dry, dusty, or windy climate, home or office air conditioning, or a dry heating system can also cause increased tear evaporation, resulting in dry eyes. Insufficient blinking during prolonged computer use can also lead to dry eyes. Long-term use of contact lenses is another cause. In reality, dry eyes are the most common complaint among contact lens wearers. The rubbing of the lenses against the conjunctiva seems to be a cause of dry eyes, making them wearers uncomfortable. Incomplete closure of the eyelids, eyelid diseases, and a deficiency of the tear-producing glands are other causes. Recent research suggests that smoking can also increase the risk of dry eye syndrome.
Eyelid surgery or blepharoplasty has recently gained popularity for enhancing the appearances of individuals. Dry eye complaints are now occasionally associated with incomplete closure of eyelids following such a procedure. The elimination of these factors often lead to marked improvement in symptoms and may cure the problem to a certain extent. Dry eyes are also a symptom of systemic diseases, such as Lupus, Rheumatoid arthritis, Rosacea, and Sjogren's syndrome (a triad of dry eyes, dry mouth, and either rheumatoid arthritis or lupus). The dry eye syndrome is more common in women, possibly due to hormone fluctuations. In some patients, the dry eye is caused either by a nonreversible deficiency of tear production or by a chronic condition leading to increased evaporation, such as blepharitis. In such cases, the disease may exhibit a chronic nature, with waxing and waning severity of symptoms or a gradual increase in the severity of symptoms with time. Many patients who have moderate to severe dry eye have been observed to develop reversible conjunctival squamous metaplasia and punctate epithelial erosions of the conjunctiva and cornea. Complications, such as ocular surface keratinization; corneal ulceration, scarring, thinning, or neo-vascularization, microbial keratitis, and sterile corneal keratolysis with possible perforation and severe visual loss are rarely observed in patients with severe dry eye.
Dry eye conditions are classified, based on the ability of the lacrimal gland to produce tears, into those with adequate tear production, and those with tear deficiency. Meibomian gland dysfunction that results in lipid tear deficiency is observed in a majority of patients with adequate tear fluid in dry eye. Aqueous tear deficiency can be subclassified into non-Sjogren's syndrome and Sjogren's syndrome (SS) groups. Patients with non-Sjogren's tear deficiency have less severe symptoms and ocular surface disease than those with SS (4).
Until recently, dry eye was considered to be a difficult to treat and time-consuming clinical condition. This led many patients to live with the condition, and many ophthalmologists to shy away from actively seeking out and treating them. The emergence of several new-generation artificial tears and wetting agents, which can be used as a prescription for dry eye medication, and new dietary supplements have made the ailment much more manageable. According to ophthalmologists, patients can be treated effectively and efficiently now. Also, a general awareness of dry eye has arisen. Pharmaceutical companies, media-marketing campaigns, and medical information on the internet have publicized the condition and have informed people regarding potential treatments. These factors have made it easy for physicians to actively seek out and treat dry eye patients. Effective diagnosis is the key for the classification and treatment of dry eye (31). The most important aspects of caring for patients with dry eye are to educate them about the chronic nature of the disease process, and to provide specific instructions for therapeutic regimen. The frequency and extent of the follow-up evaluation will depend on the severity of disease, the therapeutic approach, and the response to the therapy.
JCDR services were used in research of this article.
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