The insufficient content of the lacrimal pool between the ocular surface and the lids has recently become known with the syntagmatic term “dry eye”. Insufficient tear quantity is usually associated with poor tear quality. Dry eye is today considered as the most frequent condition in ophthalmology. The prevalence of Dry Eye syndromes changes according to the age, sex, race, geography, socio-sanitary levels and severity. If the first and last variables are considered, Mild Dry Eye affects about 1% of people under 30 years old, 20% between 30 and 60 years old, and 100% over 60 years old. Most people with mild dry eye are unaware that the symptoms they have belong to dry eye manifestations. Moderate Dry Eye affects 0.1 % of people under 30 years old, 1% between 30 and 60 years old, and 10% over 60 years old Severe Dry Eye affects about 0.002 % of people under 30 years old; 0.01% between 30 and 60 years old, and 0.1% over 60 years old. The Triple Classification of Dry Eye was approved by xero-dacryologists from all over the world. This Classification lists the main parameters to diagnose and treat a dry eye. The first are the etiologies that produce the dry eye, the second the affected glands and tissues provoking the dry eye; and the third, the severity of the disease. These three parameters are essential to establish the identification and management of each type of dry eye of the many ones that exist.