Dry Eye Syndrome

The dry eye syndrome is caused by the instability of the preocular tear film which lies on the surface of the eyeball between the eyelids. It consists of 3 layers: the outer lipid layer, middle aqueous layer and inner mucin layer (Fig. 1). The tear film can be affected by disorders of lipid, mucus or tear production in secretion glands of conjunctiva and lacrimal glands. Other causes of the dry eye syndrome are the defects of the eyeball surface and edges of the eyelids, low frequency of blinking, internal diseases and environmental and professional exposition factors (air conditioning, working with computers). The most common symptoms are irritation, foreign body sensation, burning, photophobia and complaints of dry eye. The ocular examination and special tests (Schirmer’s tests, break-up time test, rose bengal staining, LIPKOF…) are necessary for dry eye syndrome diagnosis. In some cases it is also necessary to perform the internal medical examination. If the dry eye syndrome is caused by the decreased tear production the treatment consists of application of so-called artificial tears, sometimes in combination with antiinflammatory agents. Otherwise the treatment depends on each particular cause.

Fig. 1 The preocular tear film: the outer lipid layer (green), middle aqueous layer (blue) and inner mucin layer (red).