Correlation between intraocular pressure, central corneal thickness, stage of glaucoma, and demographic patient data: prospective analysis of biophysical parameters in tertiary glaucoma practice populations.
OBJECTIVE
To determine the correlation of central corneal thickness (CCT) to Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT, PASCAL), and to glaucoma stage as assessed by cup-to-disc ratio (CDR).


METHODS
Prospective, cross-sectional tricenter observation study.


METHODS
From three glaucoma specialty practices a sample of 406 independent eyes was included. After ultrasound pachymetry, intraocular pressure was measured using PASCAL and Goldmann applanation tonometry and cup-to-disc ration was reassessed. Demographic data were included in the multivariate analysis.


RESULTS
Mean corneal thickness was 540 microm. African Americans and normal-tension glaucoma patients showed the lowest values (518 microm and 522 microm, respectively). These values were significantly thinner than the central corneal thickness of Caucasians (549 microm) and ocular hypertensives (564 microm). Intraocular pressure assessed by Goldmann applanation tonometry shows a significant correlation with central corneal thickness (r = 0.068, P < 0.001), whereas PASCAL is not significantly associated with central corneal thickness (r < 0.001, P = 0.997). Increased IOP is significantly correlated with large ocular pulse amplitudes (r = 0.13, P < 0.001), which is predominantly seen in ocular hypertensives. A significant negative correlation was detected between cup-to-disc ratio and central corneal thickness (r = 0.102, P < 0.001).


CONCLUSIONS
Glaucoma patients with thin central corneal thickness are more likely to be found at an advanced stage of the disease and among those with normal-tension glaucoma and black African ancestry. Underestimation of intraocular pressure by Goldmann applanation tonometry could be one causative factor.
Kniestedt
Christoph
C
Department of Ophthalmology, University of California, San Francisco, CA, USA. Christoph@Kniestedt.ch
Lin
Shan
S
Choe
Joyce
J
Nee
Michelle
M
Bostrom
Alan
A
Stürmer
Jörg
J
Stamper
Robert L
RL
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000208:ethnology; D044383:Black People / Q000208:ethnology; D001837:Body Weights and Measures; D002648:Child; D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D003430:Cross-Sectional Studies; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000145:classification* / Q000208:ethnology; D005902:Glaucoma, Open-Angle / Q000145:classification* / Q000208:ethnology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000145:classification; D011446:Prospective Studies; D013557:Switzerland / Q000453:epidemiology; D014065:Tonometry, Ocular; D014463:Ultrasonography; D014481:United States / Q000453:epidemiology; D014792:Visual Acuity; D044465:White People / Q000208:ethnology; D001741:Black or African American