Dry eye is a chronic condition that affects the functioning of tears and the surface of the eye, it can be due to multiple causes and it affects approximately 15% of the world’s population.
Patients with dry eye have symptoms of feeling they have a foreign body in their eye, irritation, blurring, photosensitivity, redness, stinging or itching and watering of the eyes. In the most extreme cases, the lack of tears can produce episodes of severe pain, loss of visual acuity and damage to the cornea.
Women are more likely to develop dry eye due to hormonal changes caused by circumstances such as pregnancy, oral contraceptives and menopause. It is estimated that the production of tears is reduced by almost 60% with age.
Dry eye is initially treated using artificial tears. The ophthalmologist will choose the most appropriate eye drops in each case depending on the patient’s specific characteristics, always with the ultimate objective of reducing the patient’s need for the drops.
The differences between the different types of artificial tears are due to several factors such as their electrolyte composition, osmolarity, osmolality and viscosity, which result in different duration, interference with vision and efficiency.
The composition of the tears affects the duration. The artificial tears that remain the longest are those that contain hyaluronate followed by those with cellulose and lastly those containing synthetics. The opposite occurs with the interference with vision, those that interfere the least are those composed of synthetics and those that interfere the most contain hyaluronate.
Another important aspect of composition is whether the artificial tears contain preservatives, which affects our tolerance to them. The artificial tears that do not contain preservatives are recommended as they alter the surface of the eye much less, which reduces damage in dry eyes.