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Pierre Bitoun, Pierre Chapelle, Jean-Pierre Chambard, Yves Lachkar, Vincent Pean, Laurent Benzacken; Impact of Gender-Specific Corneal Elasticity Differences upon IOP Measurements Using Vibration Tonometry.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):6464.
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© ARVO (1962-2015); The Authors (2016-present)
Contactless Vibration Tonometry enables precise IOP independently of CCT and post LASIK using corneal vibrations response to calculate IOP with gender-specific algorithms linked to elasticity which differs between men and women as previously shown. We are attempting to calculate the lack of gender information on IOP error using gender-algorithm inversion
Vibration tonometry clinical trials IOP data from 324 subjects separated the measurements in 3 IOP groups: <=16 ; >16 - <23 ; and >=23 mm Hg . We also separated the measurements in 3 age groups. 1040 and 1031 measurements were used respectively in women and in men
Using the male algorithm for females , 15/1040 aberrant results were discarded. Mean IOP difference was -.376 mm Hg (1.366 SD) versus 0.07 mmHg (1.304 SD) and 1.937(2.861 SD) respectively in the 16,16-23, and > 23 mm group. These differences were significantly different p<0.0001. When stratified by age the 3 groups of measurements showed IOP mean difference of -0.086 mm Hg (SD=1.028) 0.077 (SD=1.287) and -0.224 mm Hg ( SD= 1.497) respectively in < 50; 50-60 and > 60 yrs old. Distribution being non normal Kruskal-Wallis test used showed all 3 groups differed significantly p<0.001, compared 2 to 2 (post hoc with Bonferroni correction) the error in the 50-60 group differed significantly from that in >60 yrs group.For Men using female algorithm 22/1031 aberrant values discarded. Mean IOP difference was -.115 mm Hg (1.293 SD) group versus 0.385 ( 1.064 SD) and -1.002 (2.639SD) respectively in the <16 mm, 16-23 and 23mm Hg group. These differences were all significantly different (p<0.0009). When stratified into 3 age groups IOP mean differences were -0.129 mm Hg (SD=.973). 0.185 (SD=1.185) and 0.259 mm Hg ( SD= 1.286) respectively in men. Because of non normal distribution Kruskal-Wallis used with Bonferroni correction groups did not differ significantly p<0.056, when compared 2 to 2 the error in the <50 group differed nearly significantly from that in >60 yrs old group p=0.025
Use of gender-specific algorithms to inform IOP measurement in Vibration Tonometry shows most significant impact in the higher IOP values and in the older age group over 60 yrs old and most significantly in women who show a higher corneal elasticity than men. These analyses confirm the important need for gender-specific tonometry as uniquely provided by Vibration Tonometry
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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