title: Impact of dehydration and fasting on intraocular pressure and corneal biomechanics measured by the Ocular Response Analyzer.
abstract: OBJECTIVE
  To investigate the effects of dehydration and fasting on the intraocular pressure (IOP) and corneal biomechanics during Ramadan in healthy subjects.
  
  
  METHODS
  A total of 36 healthy fasting male volunteers with a mean age of 32.7 ± 5.1 years (range 28-38 years) were enrolled in the study. A Reichert Ocular Response Analyzer (ORA) was used to measure the corneal resistance factor (CRF), corneal hysteresis (CH), Goldman-correlated IOP (IOPg), and corneal-compensated IOP (IOPcc), additionally IOP with Goldmann applanation tonometer (IOP-GAT) was taken. All measurements were recorded at 8:00 am and 4:00 p.m. during Ramadan and during a 1-month follow-up after Ramadan was over.
  
  
  RESULTS
  Statistical analysis demonstrated no difference in the ORA measurements including CH, CRF, IOPcc, and IOPg; CCT and CV values between fasting and non-fasting periods or within a single day (diurnal changes). Nine volunteers (25% of total subjects) were excluded because eyedrops were believed to disrupt the Ramadan fast consequently IOP-GAT could not be measured from these subjects. No statistically significant difference was noted between IOP-GAT and IOPg measurements of twenty-seven subjects at the different periods and time points.
  
  
  CONCLUSIONS
  Our results reveal that fasting during Ramadan does not profoundly affect corneal biomechanics and IOP values in healthy volunteers without ocular diseases such as glaucoma. When planning corneal refractive surgery and determining IOP, the ORA measurements can be done safely during a Ramadan fast. Moreover, ORA may be a better alternative for patients that refuse IOP measurement via GAT for examining the accuracy of IOP during fasting. Further studies are needed to better understand the role of these parameters on corneal disease and glaucoma during fasting.
authors.affiliation: Department of Ophthalmology, Atatürk Training and Research Hospital, Yıldırım Beyazıt University, Ankara, Turkey. sehersertbas@gmail.com.
authors.forename: Betul Seher
authors.initials: BS
authors.lastname: Uysal
authors.affiliation: Department of Ophthalmology, Atatürk Training and Research Hospital, Yıldırım Beyazıt University, Ankara, Turkey.
authors.forename: Necati
authors.initials: N
authors.lastname: Duru
authors.affiliation: Department of Ophthalmology, Atatürk Training and Research Hospital, Yıldırım Beyazıt University, Ankara, Turkey.
authors.forename: Umut
authors.initials: U
authors.lastname: Ozen
authors.affiliation: Department of Ophthalmology, Atatürk Training and Research Hospital, Yıldırım Beyazıt University, Ankara, Turkey.
authors.forename: Mucella
authors.initials: M
authors.lastname: Arikan Yorgun
authors.affiliation: Department of Ophthalmology, Atatürk Training and Research Hospital, Yıldırım Beyazıt University, Ankara, Turkey.
authors.forename: Emine
authors.initials: E
authors.lastname: Akcay
authors.affiliation: Department of Ophthalmology, Atatürk Training and Research Hospital, Yıldırım Beyazıt University, Ankara, Turkey.
authors.forename: Mehtap
authors.initials: M
authors.lastname: Caglayan
authors.affiliation: Department of Ophthalmology, Atatürk Training and Research Hospital, Yıldırım Beyazıt University, Ankara, Turkey.
authors.forename: Nurullah
authors.initials: N
authors.lastname: Cagil
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D003315:Cornea / Q000502:physiology*; D003681:Dehydration / Q000503:physiopathology*; D005215:Fasting / Q000502:physiology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D014065:Tonometry, Ocular
keywords: Corneal hysteresis; Corneal resistance factor; Dehydration; Intraocular pressure; Religious fasting