J Korean Ophthalmol Soc.  2015 Aug;56(8):1248-1255. 10.3341/jkos.2015.56.8.1248.

The Effect of Corneal Biomechanical Factors on Ocular Pulse Amplitude in Normal Subjects

• Kwon HJ
• Lee JW
• Shin JH

• KMID: 2215078
• DOI: http://doi.org/10.3341/jkos.2015.56.8.1248

Abstract

PURPOSE
To investigate the influence of corneal biomechanical factors on ocular pulse amplitude measured using dynamic contour tonometry in normal subjects.
METHODS
The study population consisted of normal subjects who visited the outpatient clinic from January, 2014 to July, 2014. Ocular pulse amplitude was measured using dynamic contour tonometry and corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using an ocular response analyzer. We applied univariate and multivariate linear regressions to investigate the relationship between ocular pulse amplitude and corneal biomechanical factors and other ocular factors.
RESULTS
Fifty eyes of 50 patients (average age 52.8 +/- 17.2 years) were examined. The average ocular pulse amplitude was 2.90 +/- 1.04 mm Hg and the CH and CRF were 10.44 +/- 1.96 mm Hg and 11.03 +/- 2.21 mm Hg, respectively. In univariate linear regression, factors influencing ocular pulse amplitude were ocular pressure based on CRF (beta = 0.280, p = 0.049), Goldmann applanation tonometry (beta = 0.293, p = 0.039), and spherical equivalent (beta = 0.283, p = 0.047), while in multivariate linear regression the only factor influencing ocular pulse amplitude was CRF (beta = 0.686, p = 0.042).
CONCLUSIONS
A positive correlation between ocular pulse amplitude reflecting ocular perfusion pressure and CRF reflecting corneal elasticity was observed. Correlations between the 2 factors will be an important aspect in future studies regarding the influences of corneal biomechanical factors on ocular perfusion pressure in glaucoma patients.

Keyword

Corneal biomechanical factors; Dynamic contour tonometry; Ocular pulse amplitude

MeSH Terms

Ambulatory Care Facilities
Elasticity
Glaucoma
Humans
Linear Models
Manometry
Perfusion

Figure

• 

  Figure 1. (A) Scatterplot showing the correlation between intraocular pressure (IOP) measurements obtained by Goldmann applana-tion tonometer (x-axis) and dynamic contour tonometry (y-axis) (R = 0.826, p < 0.001). (B) Generalized Bland-Altman plot of the agreement between Goldmann applanation tonometer IOP measurements and dynamic contour tonometry measurements. The differ-ence between the measurements (y-axis) is plotted against the average of the measurements (x-axis). Dash-dotted lines represent 95% limits of agreement. The difference between two methods was regressed on the average of the two methods (dash line) (R = 0.357, p = 0.011). DCT = dynamic contour tonometry; GAT = Goldmann applanation tonometer.

• 

  Figure 2. (A) Scatterplot showing the correlation between intraocular pressure (IOP) measurements obtained by Ocular response an-alyzer IOPcc (x-axis) and dynamic contour tonometry (y-axis) (R = 0.751, p < 0.001). (B) Generalized Bland-Altman plot of the agreement between Goldmann applanation tonometer IOP measurements and Ocular response analyzer IOPcc measurements. The difference between the measurements (y-axis) is plotted against the average of the measurements (x-axis). Dash-dotted lines repre-sent 95% limits of agreement. The difference between two methods was regressed on the average of the two methods (dash line) (R = 0.004, p = 0.978). DCT = dynamic contour tonometry; IOPcc = corneal-compensated intraocular pressure.

Reference

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