title: The Effect of Tear Supplementation on Ocular Surface Sensations during the Interblink Interval in Patients with Dry Eye.
abstract: OBJECTIVE
  To investigate the characteristics of ocular surface sensations and corneal sensitivity during the interblink interval before and after tear supplementation in dry eye patients.
  
  
  METHODS
  Twenty subjects (41.88±14.37 years) with dry eye symptoms were included in the dry eye group. Fourteen subjects (39.13±11.27 years) without any clinical signs and/or symptoms of dry eye were included in the control group. Tear film dynamics was assessed by non-invasive tear film breakup time (NI-BUT) in parallel with continuous recordings of ocular sensations during forced blinking. Corneal sensitivity to selective stimulation of corneal mechano-, cold and chemical receptors was assessed using a gas esthesiometer. All the measurements were made before and 5 min after saline and hydroxypropyl-guar (HP-guar) drops.
  
  
  RESULTS
  In dry eye patients the intensity of irritation increased rapidly after the last blink during forced blinking, while in controls there was no alteration in the intensity during the first 10 sec followed by an exponential increase. Irritation scores were significantly higher in dry eye patients throughout the entire interblink interval compared to controls (p<0.004). NI-BUT significantly increased after HP-guar (p = 0.003) but not after saline drops (p = 0.14). In both groups, either after saline or HP-guar the shape of symptom intensity curves remained the same with significantly lower irritation scores (p<0.004), however after HP-guar the decrease was significantly more pronounced (p<0.004). Corneal sensitivity to selective mechanical, cold and chemical stimulation decreased significantly in both groups after HP-guar (p<0.05), but not after saline drops (p>0.05).
  
  
  CONCLUSIONS
  Ocular surface irritation responses due to tear film drying are considerably increased in dry eye patients compared to normal subjects. Although tear supplementation improves the protective tear film layer, and thus reduce unpleasant sensory responses, the rapid rise in discomfort is still maintained and might be responsible for the remaining complaints of dry eye patients despite the treatment.
authors: Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
authors: Lóránt
authors: L
authors: Dienes
authors: Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
authors: Huba J
authors: HJ
authors: Kiss
authors: Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
authors: Kristóf
authors: K
authors: Perényi
authors: Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
authors: Zsuzsanna
authors: Z
authors: Szepessy
authors: Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
authors: Zoltán Z
authors: ZZ
authors: Nagy
authors: Department of Photogrammetry and Geoinformatics, Budapest University of Technology and Economics, Budapest, Hungary.
authors: Árpád
authors: Á
authors: Barsi
authors: Instituto de Neurociencias, Universidad Miguel Hernandez-CSIC, San Juan de Alicante, Spain.
authors: M Carmen
authors: MC
authors: Acosta
authors: Instituto de Neurociencias, Universidad Miguel Hernandez-CSIC, San Juan de Alicante, Spain.
authors: Juana
authors: J
authors: Gallar
authors: Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
authors: Illés
authors: I
authors: Kovács
mesh_terms: D000328:Adult; D001767:Blinking; D003315:Cornea / Q000187:drug effects / Q000473:pathology; D015352:Dry Eye Syndromes / Q000188:drug therapy* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions / Q000008:administration & dosage* / Q000737:chemistry; D013666:Tears / Q000737:chemistry*
chemical_list: D009883:Ophthalmic Solutions