J Korean Ophthalmol Soc.  2015 Jan;56(1):86-92. 10.3341/jkos.2015.56.1.86.

Diagnostic Availability of Ocular Response Analyzer in Korean Patients with Normal Tension Glaucoma

• Cho AR
• Choi YJ
• Rhew JY
• Choi KR

• KMID: 2216158
• DOI: http://doi.org/10.3341/jkos.2015.56.1.86

Abstract

PURPOSE
To compare the parameters measured with the ocular response analyzer (ORA; Reichert Inc., Depew, NY, USA) between normal control subjects and patients with normal tension glaucoma (NTG) and to investigate clinical usefulness of ORA.
METHODS
Intraocular pressure (IOP) and central corneal thickness (CCT) were measured using the Goldmann applanation tonometer (GAT) in 100 eyes of 100 normal subjects and 100 eyes of 100 NTG patients. Four types of ORA parameters, corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated IOP (IOPg), and corneal-compensated IOP (IOPcc) were also measured.
RESULTS
The mean CH values were 11.2 mm Hg and 10.3 mm Hg and the mean CRF values were 10.8 mm Hg and 9.9 mm Hg in the normal subjects group and the NTG group, respectively. Mean CH and CRF were significantly lower in NTG patients (p < 0.001) and the IOPcc were higher than normal subjects (p = 0.004). IOPg was in agreement with the GAT IOP (ICC = 0.811) and IOPcc was not correlated with CCT. The cut-off value of 'IOPcc - IOPg' as the diagnostic standard parameter was -0.05 mm Hg (sensitivity; 76%, specificity; 55%).
CONCLUSIONS
IOPg measurements were similar to GAT IOP, and other ORA parameters (CH, CRF, IOPcc) were significantly different between normal subjects and NTG patients. Consequently, the difference of IOPcc and IOPg could be a useful parameter in NTG diagnosis.

Keyword

Biomechanical properties; Intraocular pressure; Normal tension glaucoma; Ocular response analyzer

MeSH Terms

Diagnosis
Humans
Intraocular Pressure
Low Tension Glaucoma*
Sensitivity and Specificity

Figure

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  Figure 1. Bland-Altman plots of the agreement between the Goldmann applanation tonometer (GAT) intraocular pressure (IOP) and Goldmann-correlated IOP (IOPg) (A), the GAT IOP and the corneal-compensated IOP (IOPcc) (B). These plots are generated by plotting the difference between the measurements against the average of the measurements. The solid line represents the trend line and the dashed lines represent the mean bias and the 95% limits of agreement. SD = standard deviation.

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  Figure 2. Receiver operating characteristics (ROC) curves of ocular response analyzer (ORA) parameters. IOPg = Goldmann-correlated intraocular pressure; IOPcc = corneal-compensated intraocular pressure factor; CRF = corneal resistance factor; CH = corneal hysteresis.

Reference

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