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Factors Affecting ORA Parameter and Comparing with NCT in Normal Korean. Jun Her MD. PhD, Sung-wook Kim MD, Jae-hwan Ahn MD Inje University, College of Medicine, Busan Paik Hospital, Busan, South Korea. We have NO financial interest. Purpose.
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Factors Affecting ORA Parameter and Comparing with NCT in Normal Korean Jun Her MD. PhD, Sung-wook Kim MD, Jae-hwan Ahn MD Inje University, College of Medicine, Busan Paik Hospital, Busan, South Korea We have NO financial interest
Purpose • To identify normal range of factors which can be measured with Ocular Response Analyzer(ORA, Depew, NY, USA) in normal Korean, and to analyze factors affecting ORA by measuring intraocular pressure of noncontact tonometer (NCT) and central corneal thickness (CCT).
Methods • Three hundred and one normal Korean subjects who did not have special ophthalmological diseases and surgeries in the past were recruited for this study.
Methods • Corneal hysteresis(CH), corneal response factor(CRF), corneal compensated IOP(IOPcc), Goldman related IOP(IOPg) were measured using ORA and the results and factors were analyzed. • The results were divided into a juveniles group(n=57) and to adult group over age 20 (n=244) and compared.
Methods Principle of ocular response analyzer (ORA)
Results Table 1. Normal ranges of ORA Parameters in Korean 1 : David Luce, David Taylor. Reichert Ocular Response Analyzer Measures Corneal Biomechanical Properties and IOP. Provides New Indicators for Corneal Specialties and Glaucoma Management.
Results “ CH and CRF were significantly higher in juvenile group ” Table 2. Comparision of ORA parameters between Juvenile group and Adult group P<0.05
Results “ No significant difference from male and female ” Table 3. Comparision of ORA parameters between Female group and Male group
Results Table 3. Statistical correlations between parameters. The red squares indicate significance with a high level of correlation. The blue squares indicatesignificance with a moderate correlation.
Summary • Among normal Koreans - CH : mean 10.7 ±1.45 mmHg, distribution 7.5~15.8 mmHg. - CRF : mean 10.40 ±1.61 mmHg, distribution 6.5~15.9 mmHg • Juvenile vs Adult - CH and CRF were significantlyhigher in juvenile group. • Statistical correlations between parameters - Positive correlation was found between CCT & NCT and CH & CRF (but the magnitude was weak (P<0.01)) - IOPcc and IOPg (as measures of IOP in ORA) had significamt correlation with IOP of NCT - In particular IOPcc appeared to be independent of corneal thickness
Conclusions(1) • Mean CH among normal Koreans were lower than those of Americans (P<0.01), indicating racial differences. • CH and CRF were significantly higher in the juvenile group, indicating difference in biomechanical properties of eye ball due to age. • IOPcc and IOPg measured in ORA have significant clinical correlation with IOP of NCT. • In particular, IOPcc will become more important as it is independent of corneal thickness which should be compensation in general measurement of IOP and reflects biomechanical properties.
Conclusions(2) • Futher investigation should be advised to determine whether IOPcc as tonometer being independent of corneal thickness and incorporating new concept of biomechanics would be more useful than IOP of NCT.