How does the dry eye manifest. Role of symptoms.

Dry eye is a process which affects the surface of the eye with a deterioration of the cornea and conjunctiva due to poor wetting and lubrication of these structures because of the poor quality or poor tear.

The direct contact of the air with the ocular surface determines changes in surface cells (metaplasia epidermizante), their metabolism is altered and the consequences are a more fast death and those cells disappearence. Moreover, the lack of tear results in loss of natural lubricant and the rubbing of the eyelids over eyes takes place, a constant microtrauma which further aggravates the process of cell dry-out, an inflammatory response is induced with release of toxic substances (cytokines) against the tissues.

We now know that the deterioration of the tear, so when it is a quantitative deficiency, as in the case of deterioration in its quality, is initially manifested by an increase in osmolarity of the particles that are dissolved in the aqueous part of tears. Hyperosmolarity causes negative conditions, toxic to the cells of the ocular surface, starting an inflammatory process that closes a vicious circle which alters increasingly tear features, makes it evaporate more quickly and dries the ocular surface because of the action of air directly on the ocular surface.

Up to now, we thought that the cases of dry eye were more frequent due to lack of tear but it has been shown that the cases with a tear of poor quality or, as happens even more often , a mixed mechanism are more frequent since in most patients, the factors we have seen above, are given more than once. This is important because it pretty changes how to approach the diagnosis and treatment, as we shall see.

  • Dry eye is characterized by aprematurerupture ofthe tear film andthe airdirectly contacts theocularsurface, triggering disruption oftissues, metaplasia epidermizante, which is aggravated by thehyperosmolarityof the tear andsecondaryinflammation.
  • In most cases, altered meibomian gland are present, a major cause of premature evaporation of the tear. It is essential the study of this glands for the diagnostic and treatment to solve dry eye.

Nowadays, we are concerned about the two main factors in dry eye; the deterioration of the ocular surface and the alteration of the meibomian glands, a type of glands found in the eyelids and responsible of secreting lipids (fat), which are mixed with the tear, creating the outer layer of the tear film and so avoiding rapid evaporation. When these glands are altered, generally by obstruction, no lipid secretion is done and the tear film is broken in a few seconds with a rapid evaporation, exposing the cells of the ocular surface directly to the air.

The most recent studies on dry eye make special emphasis on the role of the meibomian glands in the genesis of the disease. The glands would be impaired in a 80% of cases of dry eye, hence the importance of studying them in order to value their state.

The symptoms of dry eye include the appearance of typical discomforts, such as the feeling of having sand or strange small beings, especially in the morning, in closed dry places with air conditioning or heating and on windy days.

  • Patients with dry eye complain of discomfort when open their eyes in the morning and grittiness or burning (variable course), throughout the day.
  • Usually, these patients have fluctuating vision, and difficulty in performing tasks such as reading or computer, which requires stare.
  • In most cases there is a feeling of frustration and anxiety to see how the disease does not just heal and not let them perform their daily tasks, compounded by the lack of understanding of the people around them status.
  • The shape of clinically manifest dry eye is the appearance of the typical symptoms of grittiness or foreign body sensation, especially in the mornings, which increased discomfort in enclosed dry rooms with air conditioning or heating or very windy days.

Often patients complain of impaired vision, fluctuating vision and inability to stare too long in activities such as reading, computer or anything that involves an effort of attention.

ojo seco ordenador
problemas ojo seco ordenador

Patients suffering from these disorders, especially in cases with a major life activity, can account for a major problem, as they lack capacity to work, create insecurity and can reach a situation of significant frustration, worsening with a sense of incomprehension about people around them. In some cases it is necessary to explain to the family the problem of dry eye, so they can help the patient.