Assessment of the diurnal variation in central corneal thickness and intraocular pressure for patients with suspected glaucoma

Ophthalmology. 2000 Jun;107(6):1191-3. doi: 10.1016/s0161-6420(00)00090-7.


Objective: To assess whether a single daily measurement using ultrasonic pachymetry gives a representative assessment of mean central corneal thickness (CCT) in patients with suspected glaucoma and whether diurnal changes in CCT are related to diurnal variations in intraocular pressure (IOP).

Design: Cross-sectional study.

Method: Central CCT and IOP were measured by a single observer in 56 eyes of 28 patients with suspected glaucoma using an ultrasonic pachymeter and a Goldmann tonometer. Four measurements were made over a 24-hour period: at 8:00 AM, 12:00 PM, 4:00 PM, and 8:00 PM.

Main outcome measures: Intraocular pressure and pachymetry.

Results: Mean IOP was 19.80 mmHg at 8:00 AM (95% confidence interval [CI], 18.95-20.66 mmHg), 20.38 mmHg at 12:00 PM (95% CI, 19.49-21.26 mmHg), 19.91 mmHg at 4:00 PM (95% CI, 19.99-21.83 mmHg), and 19.23 mmHg at 8:00 PM (95% CI, 18.35-20.11 mmHg). Mean CCT was 569.4 microm (95% CI, 560.2-578.7 microm), 567.6 microm (95% CI, 558.4-576.7 microm), 569.1 microm (95% CI, 559.5-578.6 microm), and 567.2 microm (95% CI, 557.9-576.4 microm) at the four respective time points. There was no significant correlation between IOP and CCT in any patient (Pearson rank correlation coefficient); nor was there any significant correlation between the mean diurnal variations of IOP and CCT.

Conclusions: In this group of patients with suspected glaucoma, there was no significant variation in CCT. Therefore, a single measurement of CCT is sufficient when assessing patients with suspected glaucoma. There was no correlation between change of IOP and change of CCT.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Circadian Rhythm*
  • Cornea / anatomy & histology*
  • Cross-Sectional Studies
  • Female
  • Humans
  • Intraocular Pressure / physiology*
  • Male
  • Middle Aged
  • Ocular Hypertension / diagnosis
  • Ocular Hypertension / physiopathology*
  • Tonometry, Ocular