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The relationship between diurnal variations in intraocular pressure measurements and central corneal thickness and corneal hysteresis.
Invest Ophthalmol Vis Sci 2009; 50(9):4229-36IO

Abstract

PURPOSE

To examine the relationship between office-hour changes in IOP, measured with the Goldmann applanation tonometer (GAT) and dynamic contour tonometer (DCT), and the corneal characteristics central corneal thickness (CCT) and corneal hysteresis (CH).

METHODS

Sixty-two eyes of 62 untreated normal subjects and patients with untreated glaucoma had IOP measurements performed with the GAT (mm Hg) and DCT (mm Hg) over an 8-hour period at 2-hour intervals beginning at 9 AM. CCT (micrometers) was measured using a noncontact optical low-coherence reflectometry (OLCR) pachymeter, and CH (mm Hg) was measured with an ocular response analyzer (ORA). The associations between IOP measurements and corneal characteristics for each patient over the measurement period were assessed by using multilevel modeling.

RESULTS

GAT and DCT IOP and CCT changed significantly during office hours (ANOVA; GAT: F = 19.9, P < 0.001; DCT: F = 4.6, P = 0.001; CCT: F = 16.4; P < 0.001). No significant changes were observed in CH (ANOVA; F = 1.8, P = 0.13). Multilevel modeling analysis of the interrelationships between CCT, CH, and age on IOP measurements revealed that both CCT and CH changes were significantly associated with GAT IOP changes (GAT IOP/CCT slope, 0.04 mm Hg/microm; 95% confidence intervals [CIs], 0.02-0.06; GAT IOP/CH slope, 0.20 mm Hg/mm Hg; 95% CI, 0.01-0.39). CCT, but not CH, changes were significantly associated with DCT IOP changes (DCT IOP/CCT slope, 0.03 mm Hg/microm; 95% CI, 0.00-0.05). However, although the association between CCT and GAT IOP was relatively uniform between subjects, association between CCT and DCT IOP showed greater intersubject variability. Age had no effect on the diurnal variation of IOP measured with either device.

CONCLUSIONS

Measured IOP and corneal characteristics covary during office hours. Changes in CCT and CH are associated with changes in GAT IOP and, less consistently, with DCT IOP. The data suggest that variations in corneal characteristics explain a small proportion of the change in IOP measurements made with the GAT during office hours.

Authors+Show Affiliations

National Institute for Health Research Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital National Health Service Foundation Trust and the UCL Institute of Ophthalmology, London, United Kingdom.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19407025

Citation

Kotecha, Aachal, et al. "The Relationship Between Diurnal Variations in Intraocular Pressure Measurements and Central Corneal Thickness and Corneal Hysteresis." Investigative Ophthalmology & Visual Science, vol. 50, no. 9, 2009, pp. 4229-36.
Kotecha A, Crabb DP, Spratt A, et al. The relationship between diurnal variations in intraocular pressure measurements and central corneal thickness and corneal hysteresis. Invest Ophthalmol Vis Sci. 2009;50(9):4229-36.
Kotecha, A., Crabb, D. P., Spratt, A., & Garway-Heath, D. F. (2009). The relationship between diurnal variations in intraocular pressure measurements and central corneal thickness and corneal hysteresis. Investigative Ophthalmology & Visual Science, 50(9), pp. 4229-36. doi:10.1167/iovs.08-2955.
Kotecha A, et al. The Relationship Between Diurnal Variations in Intraocular Pressure Measurements and Central Corneal Thickness and Corneal Hysteresis. Invest Ophthalmol Vis Sci. 2009;50(9):4229-36. PubMed PMID: 19407025.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The relationship between diurnal variations in intraocular pressure measurements and central corneal thickness and corneal hysteresis. AU - Kotecha,Aachal, AU - Crabb,David P, AU - Spratt,Alexander, AU - Garway-Heath,David F, Y1 - 2009/04/30/ PY - 2009/5/2/entrez PY - 2009/5/2/pubmed PY - 2009/9/19/medline SP - 4229 EP - 36 JF - Investigative ophthalmology & visual science JO - Invest. Ophthalmol. Vis. Sci. VL - 50 IS - 9 N2 - PURPOSE: To examine the relationship between office-hour changes in IOP, measured with the Goldmann applanation tonometer (GAT) and dynamic contour tonometer (DCT), and the corneal characteristics central corneal thickness (CCT) and corneal hysteresis (CH). METHODS: Sixty-two eyes of 62 untreated normal subjects and patients with untreated glaucoma had IOP measurements performed with the GAT (mm Hg) and DCT (mm Hg) over an 8-hour period at 2-hour intervals beginning at 9 AM. CCT (micrometers) was measured using a noncontact optical low-coherence reflectometry (OLCR) pachymeter, and CH (mm Hg) was measured with an ocular response analyzer (ORA). The associations between IOP measurements and corneal characteristics for each patient over the measurement period were assessed by using multilevel modeling. RESULTS: GAT and DCT IOP and CCT changed significantly during office hours (ANOVA; GAT: F = 19.9, P < 0.001; DCT: F = 4.6, P = 0.001; CCT: F = 16.4; P < 0.001). No significant changes were observed in CH (ANOVA; F = 1.8, P = 0.13). Multilevel modeling analysis of the interrelationships between CCT, CH, and age on IOP measurements revealed that both CCT and CH changes were significantly associated with GAT IOP changes (GAT IOP/CCT slope, 0.04 mm Hg/microm; 95% confidence intervals [CIs], 0.02-0.06; GAT IOP/CH slope, 0.20 mm Hg/mm Hg; 95% CI, 0.01-0.39). CCT, but not CH, changes were significantly associated with DCT IOP changes (DCT IOP/CCT slope, 0.03 mm Hg/microm; 95% CI, 0.00-0.05). However, although the association between CCT and GAT IOP was relatively uniform between subjects, association between CCT and DCT IOP showed greater intersubject variability. Age had no effect on the diurnal variation of IOP measured with either device. CONCLUSIONS: Measured IOP and corneal characteristics covary during office hours. Changes in CCT and CH are associated with changes in GAT IOP and, less consistently, with DCT IOP. The data suggest that variations in corneal characteristics explain a small proportion of the change in IOP measurements made with the GAT during office hours. SN - 1552-5783 UR - https://www.unboundmedicine.com/medline/citation/19407025/The_relationship_between_diurnal_variations_in_intraocular_pressure_measurements_and_central_corneal_thickness_and_corneal_hysteresis_ L2 - http://iovs.arvojournals.org/article.aspx?doi=10.1167/iovs.08-2955 DB - PRIME DP - Unbound Medicine ER -