Correlation between Corneal Biomechanics and Intraocular Pressure | ||
| The Egyptian Journal of Hospital Medicine | ||
| Article 1, Volume 71, Issue 6, April 2018, Pages 3273-3284 PDF (651.15 K) | ||
| Document Type: Original Article | ||
| Author | ||
| Mahmoud Ibrahim Elgammal, Mohammed Abdel-Monem Mahdy, Mahmoud Mohammad Saleh | ||
| Department of Ophthalmology, faculty of medicine, Al-Azhar University, Cairo, Egypt | ||
| Abstract | ||
| Background: measurement error in goldman applanation tonometry (GAT) may be due to the differences in central corneal thickness (CCT) or corneal stromal rigidity. Corneal hysteresis (CH) and corneal resistance factor (CRF) may prove a helpful guide to measure this relationship. Purpose: To study the correlation between cornea biomechanical parameters as measured with the Ocular Response Analyzer (ORA) and intraocular pressure (IOP). Patient and Method: The study is a comparative prospective cross-sectional clinical trial included 60 eyes of patients subdivided into three groups; 20 with primary open angle glaucoma (POAG), 20 with ocular hypertension (OHT) and 20 as normal population. They underwent measurement of IOP, CCT and corneal biomechanical parameters (CH, CRF) using GAT, ORA and ultrasound pachymetery. Results: Thirty patients were enrolled in the study, 22 males (73%) and 8 females (27%). The mean age of patients involved is 44.2 ± 12.6 ranging between 25 and 60 years old. The IOP by GAT, IOPg and IOPcc were 21.6 ± 5.1, 21.5 ± 5.1, 22.1 ± 5.1 respectively. The CH and CRF were 14.2 ± 9.3 and 18 ± 11.2. The CCT was 531.97 ± 20.4. The correlation is insignificant between all parameters of IOP and CCT (P >0.05) while the correlation is significant between IOP and corneal biomechanics and between CCT and corneal biomechanics (P < 0.05). Conclusion: CCT affect corneal biomechanical properties, the higher CCT the higher were CH and CRF and vice versa. Corneal biomechanics affect IOP more than CCT. The higher CH the lower was IOP while the higher CRF the higher was IOP. CH affect IOPcc more than GAT while CRF affect GAT more than IOPcc. CH decrease in glaucoma and in OHT more than normal while CRF increase in glaucoma and OHT more than normal. | ||
| Keywords | ||
| Intraocular pressure – Ocular Response Analyzer – Goldmann Applanation Tonometry – Corneal biomechanics | ||
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