Dry eye is a condition in which there are insufficient tears to lubricate and nourish the eye. Tears are necessary for maintaining the health of the front surface of the eye and for providing clear vision. People with dry eyes either do not produce enough tears or have a poor quality of tears. Dry eye is a common and often chronic problem, particularly in older adults. With each blink of the eyelids, tears are spread across the front surface of the eye, known as the cornea.
A long string of land pressed between the Pacific and the towering Andes, Chile is 4,270 km (2,653 mi) long. â. ; it is 356 km (221 mi) wide at its broadest point (just north of Antofagasta) and 64 km (40 mi) wide at its narrowest point, with an average width of 175 km (109 mi). â. .
Situated south of Peru and west of Bolivia and Argentina, Chile fills a narrow 2,880-mi (4,506 km) strip between the Andes and the Pacific. One-third of Chile is covered by the towering ranges of the Andes.