title: Hydroxypropyl-guar gellable lubricant eye drops for dry eye treatment.
abstract: BACKGROUND
  Dry eye is a medical problem of epidemic proportions, especially among the elderly in developed countries. The treatment of dry eye is still largely inadequate because there is no way of permanently restoring normal tear function and secretion at present. At present, virtually all therapeutic regimens include tear supplements; however, their main drawbacks are the need for frequent instillation, inadequate ocular surface protection and limited mode of action, focusing on rewetting only.
  
  
  OBJECTIVE
  A new gellable lubricant eye drop (Systane lubricant eye drops, Alcon) has been designed using the novel concept of a pH-sensitive hydroxypropyl-guar component that prevents surface desiccation, reduces friction and acts as a mucomimetic. The purpose of this review is to consider this topical therapy and its properties.
  
  
  METHODS
  Currently published data on Systane is reviewed, putting an accent on its novel multiple modality of action.
  
  
  CONCLUSIONS
  By being pH sensitive, Systane adapts its viscosity to the ocular surface pH, which tends to be higher in dry eye. It becomes more viscous when the eye is drier, thus, providing better ocular surface protection. In addition, its characteristics reduce ocular surface friction, which is another factor that exacerbates dry eye symptoms. Data published so far show that it is also well tolerated by the patient, thus, significantly reducing dry eye symptoms and improving the patient's quality of life. By implementing this novel approach, Systane has contributed significantly to dry eye treatment.
authors.affiliation: Zagreb University Hospital, Department of Ophthalmology, Kispaticeva 12, HR-10000 Zagreb, Croatia. igor.Petricek@zg.t-com.hr
authors.forename: Igor
authors.initials: I
authors.lastname: Petricek
authors.forename: András
authors.initials: A
authors.lastname: Berta
authors.forename: Mohamed T
authors.initials: MT
authors.lastname: Higazy
authors.forename: János
authors.initials: J
authors.lastname: Németh
authors.forename: Marek E
authors.initials: ME
authors.lastname: Prost
mesh_terms: D000287:Administration, Topical; D002986:Clinical Trials as Topic; D015352:Dry Eye Syndromes / Q000188:drug therapy* / Q000453:epidemiology; D005782:Gels / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008153:Lubrication; D009883:Ophthalmic Solutions; D011134:Polysaccharides / Q000737:chemistry*; D011788:Quality of Life; D014783:Viscosity
chemical_list: D005782:Gels; D009883:Ophthalmic Solutions; D011134:Polysaccharides; C519976:hydroxypropyl guar