Dry Eye is a common disorder that can cause irritation and blurry vision when tears fail to lubricate the eye. This failure can be due either to an inadequate production of tears or to the poor quality of the tears. Tears are made up of three layers: an oil layer, water layer and mucus layer. The water layer keeps the eye moist while the oil layer protects the water layer from evaporating. The mucus layer helps to spread the tears evenly over the eye. If there are deficiencies in any of these layers, you can experience the symptoms of dry eye.