[Dry eye syndrome--multispecialistic disease. Part one: Pathogenesis, signs, classification]

The authors presents the review of the literature concerning on the signs, classification, connections between the dry eye syndrome and other diseases and the risk factors of dry eye syndrome. It is a prevalent, multifactorial disease that is particularly frequent in elderly patients and women, especially in menopausal and postmenopausal period. Dry eye syndrome can be episodic with transient signs and symptoms or chronic with persistent signs and symptoms and is characterized by one or more of the following symptoms: burning, itching, foreign body sensation, soreness, dryness, photophobia, redness, and reduced visual acuity. The tear film instability of dry eye syndrome, which is accompanied by increased osmolarity of the tear film, causes inflammation and structural damage to the ocular surface. There are two major etiologic categories of dry eye syndrom: aqueous-deficient and evaporative. The most frequent classification of dry eye for practical clinical use is triple classification based on the ethiology, histopathological changes and severity of the disease.