title: Vasoactive intestinal peptide, a promising agent for myopia?
abstract: OBJECTIVE
  To investigate the role of vasoactive intestinal peptide (VIP) in form-deprivation myopia (FDM).
  
  
  METHODS
  FDM was created in three groups of eight chicks by placing a translucent diffuser on their right eyes. Intravitreal injections of saline and VIP were applied once a day into the occluded eyes of groups 2 and 3, respectively. Retinoscopy and axial length (AL) measurements were performed on the first and 8thdays of diffuser wear. The retina mRNA levels of the VIP receptors and the ZENK protein in right eyes of the three groups and left eyes of the first group on day 8 were determined using real time polymerase chain reaction (PCR).
  
  
  RESULTS
  The median final refraction (D) in right eyes were -13.75 (-16.00, -12.00), -11.50 (-12.50, -7.50), and -1.50 (-4.75, -0.75) in groups 1, 2, and 3, respectively (P<0.001). The median AL (mm) in right eyes were 10.65 (10.00, 11.10), 9.90 (9.70, 10.00), and 9.20 (9.15, 9.25) in groups 1, 2, and 3, respectively (P<0.001). The median delta-delta cycle threshold (CT) values for the VIP2 receptors were 1.07 (0.82, 1.43), 1.22 (0.98, 1.65), 0.29 (0.22, 0.45) in right eyes of groups 1, 2, and 3, and 1.18 (0.90, 1.37) in left eyes of group 1, respectively (P=0.001). The median delta-delta CT values for the ZENK protein were 1.07 (0.63, 5.03), 3.55 (2.20, 5.55), undetectable in right eyes of groups 1, 2, and 3 and 1.89 (0.21, 4.73) in left eyes of group 1, respectively (P=0.001).
  
  
  CONCLUSIONS
  VIP has potential inhibitory effects in the development of FDM.
authors.affiliation: Department of Ophthalmology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26180, Turkey.
authors.forename: Ayse Idil
authors.initials: AI
authors.lastname: Cakmak
authors.affiliation: Department of Ophthalmology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26180, Turkey.
authors.forename: Hikmet
authors.initials: H
authors.lastname: Basmak
authors.affiliation: Department of Ophthalmology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26180, Turkey.
authors.forename: Huseyin
authors.initials: H
authors.lastname: Gursoy
authors.affiliation: Department of Physiology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26180, Turkey.
authors.forename: Mete
authors.initials: M
authors.lastname: Ozkurt
authors.affiliation: Department of Ophthalmology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26180, Turkey.
authors.forename: Nilgun
authors.initials: N
authors.lastname: Yildirim
authors.affiliation: Department of Physiology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26180, Turkey.
authors.forename: Nilufer
authors.initials: N
authors.lastname: Erkasap
authors.affiliation: Department of Ophthalmology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26180, Turkey.
authors.forename: Mustafa Deger
authors.initials: MD
authors.lastname: Bilgec
authors.affiliation: Department of Physiology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26180, Turkey.
authors.forename: Nese
authors.initials: N
authors.lastname: Tuncel
authors.affiliation: Department of Biostatistics, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26180, Turkey.
authors.forename: Ertugrul
authors.initials: E
authors.lastname: Colak
keywords: ZENK protein; chicks; form-deprivation myopia; myopia; vasoactive intestinal peptide; vasoactive intestinal peptide receptor