Amr Abdel-Fattah Gab-Alla
Journal of the Egyptian Ophthalmological Society 2015 108(4):202-208
Aim The aim of this study was to determine intraocular pressure (IOP) and corneal biomechanical properties in myopic patients in Suez Canal area in Egypt. Materials and methods A total of 350 eyes of myopic patients (n = 179, age = 29.4 ± 8.9 years) with a mean refractive errors of spherical equivalent (SE) ± SD of -5.00D+2.8 D were recruited in this study. All participants in this study underwent standardized ocular examinations. Metrics of corneal biomechanical properties, including corneal hysteresis (CH), corneal resistance factor (CRF), and central corneal thickness (CCT), were measured with the ocular response analyzer (ORA). The ORA also determined the values of IOP [Goldmann-correlated intraocular pressure (IOPg)] and corneal-compensated intraocular pressure (IOPcc). Results The mean CH was 9.3 ± 1.4. The mean CRF was 9.7 ± 1.6. The mean CCT was 535.1 ± 37.7 μm. The mean IOPg was 16.3 ± 3.13 mmHg and the mean IOPcc was 17.8 ± 2.9 mmHg. The relationship between CH, CRF, and CCT and between CRF and CH was significant (P < 0.0001). There was a negative correlation between CH and IOPcc and a positive correlation between IOPcc and refractive errors. IOPcc measured using ORA is greater than IOPg by 11.2% (P < 0.0001). The cutoff point of IOPcc was 19.2 mmHg. CH and CRF decreased in aged participants. Conclusion CH and CRF of myopic Egyptians measured using the ORA have a positive but moderate correlation with CCT; the higher the CCT the higher the hysteresis and CRF.
Journal of the Egyptian Ophthalmological Society 2015 108(4):202-208
Aim The aim of this study was to determine intraocular pressure (IOP) and corneal biomechanical properties in myopic patients in Suez Canal area in Egypt. Materials and methods A total of 350 eyes of myopic patients (n = 179, age = 29.4 ± 8.9 years) with a mean refractive errors of spherical equivalent (SE) ± SD of -5.00D+2.8 D were recruited in this study. All participants in this study underwent standardized ocular examinations. Metrics of corneal biomechanical properties, including corneal hysteresis (CH), corneal resistance factor (CRF), and central corneal thickness (CCT), were measured with the ocular response analyzer (ORA). The ORA also determined the values of IOP [Goldmann-correlated intraocular pressure (IOPg)] and corneal-compensated intraocular pressure (IOPcc). Results The mean CH was 9.3 ± 1.4. The mean CRF was 9.7 ± 1.6. The mean CCT was 535.1 ± 37.7 μm. The mean IOPg was 16.3 ± 3.13 mmHg and the mean IOPcc was 17.8 ± 2.9 mmHg. The relationship between CH, CRF, and CCT and between CRF and CH was significant (P < 0.0001). There was a negative correlation between CH and IOPcc and a positive correlation between IOPcc and refractive errors. IOPcc measured using ORA is greater than IOPg by 11.2% (P < 0.0001). The cutoff point of IOPcc was 19.2 mmHg. CH and CRF decreased in aged participants. Conclusion CH and CRF of myopic Egyptians measured using the ORA have a positive but moderate correlation with CCT; the higher the CCT the higher the hysteresis and CRF.