title: Correlations between parameters of aqueous humor dynamics and the influence of central corneal thickness.
abstract: OBJECTIVE
  The individual parameters of aqueous humor dynamics may influence each other to maintain intraocular pressure (IOP) homeostasis. Central corneal thickness (CCT) is known to be associated with onset and progression of glaucoma and can potentially influence the individual parameters of aqueous humor dynamics that maintain IOP. This study investigates the correlation between parameters of aqueous humor dynamics and the influence of CCT in healthy volunteers and compares it with the correlations seen in patients with ocular hypertension.
  
  
  METHODS
  Aqueous humor dynamics (aqueous flow, outflow facility, and uveoscleral outflow), IOP, and pachymetry data from 94 healthy ocular normotensive (ONT) volunteers and 63 ocular hypertensive (OHT) patients was analyzed retrospectively. Linear correlations between individual aqueous humor dynamics parameters and pachymetry were evaluated using scatter plots and the Spearman correlation coefficient where appropriate.
  
  
  RESULTS
  In both groups, a significant (P < 0.05) negative correlation was found between corneal thickness and aqueous flow (ONT, R(2) = 0.14; OHT, R(2) = 0.10) and between corneal thickness and uveoscleral outflow (ONT and OHT, R(2) = 0.10). A significant (P < 0.05) positive correlation was found between aqueous flow and outflow facility (ONT, R (2) = 0.24; OHT, R(2) = 0.10). In healthy controls, but not OHT patients, a significant (P < 0.001) positive correlation was found between aqueous flow and uveoscleral outflow (R(2) = 0.15).
  
  
  CONCLUSIONS
  Thicker corneas may be associated with lower aqueous production and lower uveoscleral outflow. The interplay between parameters of aqueous humor dynamics suggests possible autoregulatory mechanisms in the eye. OHT may differ from ONT subjects in their inability to increase the uveoscleral outflow with increases in aqueous inflow.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA. vgulati@unmc.edu
authors.forename: Vikas
authors.initials: V
authors.lastname: Gulati
authors.forename: Deepta A
authors.initials: DA
authors.lastname: Ghate
authors.forename: Carl B
authors.initials: CB
authors.lastname: Camras
authors.forename: Carol B
authors.initials: CB
authors.lastname: Toris
mesh_terms: D001082:Aqueous Humor / Q000378:metabolism*; D003315:Cornea / Q000033:anatomy & histology / Q000378:metabolism / Q000473:pathology*; D005260:Female; D015590:Fluorophotometry; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000378:metabolism / Q000473:pathology*; D009929:Organ Size; D012189:Retrospective Studies; D014065:Tonometry, Ocular