الفهرس 
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Abstract
It has been known for many years that Dry Eye Syndrome (DES) is a common clinical problem. Surveys over the last 20 years have estimated the prevalence of DES to be between 5% to more than 30% at various ages. The prevalence increases with age. In addition to age, other factors may increase the risk of DES, such as, autoimmune diseases and post-Menopausal estrogen therapy, which has been associated with a 70 % increase in risk of dry eye. Other risk factors may include chronic diseases such as diabetes mellitus, a diet rich in high fatty acids and use of certain medications such as steroids. Evidence from epidemiological studies suggests additional risk factors may be involved including cigarette smoking.
Smoking is the major preventable risk factor for AMD. Smoking cause oxidative damage in the retina, reduces blood flow in eye tissue, and promotes ischaemia, hypoxia, and micro-infarctions. Smokers are more likely to suffer from all types of AMD, more likely to relapse after laser treatment and more likely to develop the disease ten years earlier than non-smokers
Anterior ischaemic optic neuropathy is an eye disease that results in a sudden, painless loss of vision, often leading to permanent blindness.
Smoking cigarettes undermined the tear film and ocular surface by decreasing both the quantity and quality of tear secretion, reducing corneal. It is therefore recommended that patients with dry eye syndrome and ocular surface disorders avoid smoking, even if they do not have severe dry eye presentation.
DES is a multifactorial disorder of the tear film and ocular surface that results in eye discomfort, visual disturbance, and possible ocular surface damage. Dysfunction of any Lacrimal Functional Unit (LFU)component can lead toDES by altering the volume, composition, distribution, and/or clearance of the tear film. There are two major etiologic categories of DES: aqueous deficient and evaporative.
Clinical features of DES include an unstable tear film, ocular surfacenflammation, and epitheliopathy, resulting in symptoms ranging from discomfort to blindness.
Currently there are no uniform diagnostic criteria. DES is considered a symptomatic disease; assessment of symptoms is considered of primary importance, and may be aided by use of a validated symptom questionnaire.
Combinations of various diagnostic tests (including measurements of tear film instability, ocular surface damage, and aqueous tear flow) have been used to evaluate clinical signs, but although diagnostic tests are useful for confirming the diagnosis, they often correlate poorly with symptoms. Measurement of tear osmolarity might provide a “gold standard” of diagnosis, but a practical tear osmolarity test is not yet widely available. Measurement of tear film instability by means of a TBUT test has good overall accuracy and may be more repeatable than many other diagnostic tests
An established sequence of diagnostic tests is desirable to prevent one test from interfering with another. They include clinical diagnostic tests such as Grading ocular surface staining, Tear break up time, and Schirmer’s test. Histopathological tests such as impression cytology, conjunctival and labial salivary gland biopsy. Laboratory tests include Tear fluorescein clearance, tear function index, tear osmolarity, analysis of protein, lactoferrin, tear lysozyme and leukocyte esterase in tears. Study of lipid layer that involves meibometry, lipid layer thickness, and lipid layer appearance.
The management of DES encompasses both pharmacologic and non-pharmacologic approaches, including avoidance of exacerbating factors, eyelid hygiene, tear supplementation, tear retention, tear stimulation, anti-inflammatory agents and surgery as mucus membrane, salivary gland, amniotic membrane, limbal stem cell transplantation, lid surgery and The management of DES encompasses both pharmacologic and non-pharmacologic approaches, including avoidance of exacerbating factors, eyelid hygiene, tear supplementation, tear retention, tear stimulation, anti-
inflammatory agents and surgery as mucus membrane, salivary gland, amniotic membrane, limbal stem cell transplantation, lid surgery and tarsorrhaphy.
The overall purpose of this study, therefore, is to determine whether cigarette smokers are more likely to present with the symptoms and signs of dry eye disease.