Purchase this article with an account.
Youn Hea Jung, Hae-Young Lopilly Park, Chan Kee Park; Characteristics of cornea biomechanical responses detected by noncontact Scheimpflug-based tonometer in eyes with glaucoma . Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):6135.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The relationship between glaucoma and corneal biomechanical properties has gained increasing focus, and Corvis-ST, a recently-developed tonometer which is based on an ultra-high-speed Scheimpflug technology, could reflect the corneal biomechanical changes in vivo in glaucomatous eyes. The purpose of this study was to examine and compare the corneal biomechanical properties between normal control and eyes with glaucoma using Corvis-ST, and to compare them according to glaucoma severity as defined by visual field damage.<br /> <br />
Total of 211 patients, including 75 normal control and 136 eyes with glaucoma (53 mild, 44 moderate, and 39 severe glaucomatous eyes graded according to visual field defect) were included in this cross-sectional study. Corneal biomechanical responses were examined using a noncontact Scheimpflug-based tonometer, Corvis ST. To verify the repeatability of Corvis ST parameters, intraclass correlation coefficients were calculated. Corvis-ST parameters in normal control group were compared with the glaucoma group, including analysis of glaucoma subgroups categorized by visual field loss.<br /> <br />
There were no differences in age, keratometry, spherical equivalent, axial length, central corneal thickness among the normal control group and glaucoma subgroups. Deformation amplitude was smaller in the glaucoma group (1.06 ± 0.13 mm) than the normal control group (1.11 ± 0.10 mm; P value = 0.002). The deformation amplitude decreased as central corneal thickness increased in normal control group (r = -0.235), which showed weaker relationship in mild glaucoma group (r = -0.099). In moderate (1.09 ± 0.11 mm) and severe (1.12 ± 0.14 mm) glaucoma groups, deformation amplitude was larger compared to mild glaucoma group (1.03 ± 0.12 mm). The deformation amplitude decreased as central corneal thickness decreased, showing inverse relationship in moderate and severe glaucoma groups. The usage duration and number of antiglaucomatous eyedrops had negative correlation with central corneal thickness in moderate and severe glaucomatous eyes.
Glaucomatous eyes had significantly less deformable cornea compared to non-glaucomatous eyes with similar central corneal thickness and keratometry. However, corneal deformability increased as glaucoma severity increased, which seems to be related to the use of antiglaucomatous eyedrops that affected the cornea.
This PDF is available to Subscribers Only