title: Diadenosine polyphosphates after laser in situ keratomileusis and photorefractive keratectomy refractive techniques.
abstract: OBJECTIVE
  To study the concentrations of diadenosine polyphosphates in the ocular surface after PRK and LASIK.
  
  
  METHODS
  Sixty-one patients (30 males and 31 females) with ages ranging from 20 to 63 (34.04 ± 9.13 years) were recruited in Balear Institute of Ophthalmology, Palma de Mallorca, Spain. LASIK was performed in 92 eyes of 46 patients and PRK in 25 eyes of 15 patients. Variations in the levels of diadenosine polyphosphate (Ap4 A and Ap5 A), Schirmer I (Jones test), TBUT, corneal staining together with the Dry Eye Questionnaire to evaluate discomfort and dryness were studied. All tests were performed at the preoperative visit and at 1-day, 2-week, 1-month and 3-month postoperative visits.
  
  
  RESULTS
  Ap4 A showed a 5 and 3.5 fold increase at the 1-day visit for LASIK and PRK, respectively. LASIK patients continued having higher statistically significant concentrations (p = 0.01) all over the follow-up. Ap5 A showed no significant differences at any visit. Tear volume decreased during the 3 months in LASIK. The PRK cases had a normal volume at 1 month. TBUT in LASIK increased at the 1-day visit (p = 0,002) and decreased from the 2 weeks onwards and for the PRK, decreased by a 35% at the 1-day visit and kept reduced for a month. Discomfort only increased at the 1-day visit (p = 0.007). Dryness frequency was similar in all visits.
  
  
  CONCLUSIONS
  Ap4 A levels only are increased in refractive surgery patients during the first day after the surgery. This increasing suggests that Ap4 A may help accelerating the healing process.
authors.affiliation: Department of Optics II (Optometry and Vision), Faculty of Optics, Universidad Complutense de Madrid, Madrid, SpainInstituto Balear de Oftalmología, Palma de Mallorca, SpainDepartment of Biochemistry and Molecular Biology IV, Faculty of Optics, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Carracedo
authors.forename: Isabel
authors.initials: I
authors.lastname: Cacho
authors.forename: Juan
authors.initials: J
authors.lastname: Sanchez-Naves
authors.forename: Jesus
authors.initials: J
authors.lastname: Pintor
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid; D015226:Dinucleoside Phosphates / Q000378:metabolism*; D015352:Dry Eye Syndromes / Q000175:diagnosis; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery; D018903:Photorefractive Keratectomy; D011795:Surveys and Questionnaires; D013666:Tears / Q000378:metabolism*; D014945:Wound Healing / Q000502:physiology; D055815:Young Adult
chemical_list: D015226:Dinucleoside Phosphates; D005136:Eye Proteins; C042434:tear proteins; C012275:P(1),P(5)-di(adenosine-5'-)pentaphosphate; C020733:diadenosine tetraphosphate
keywords: LASIK; PRK; dinucleotides; dry eye; wound healing