Corneal Biomechanics after Trabeculectomy, Phaco-Trabeculectomy, Ahmed Glaucoma Valve Implantation and Phacoemulsification

بيست و يكمين كنگره سراسري چشم پزشكي ايران

23 الي 26 آبان 1390، تهران - ايران

Presentation Type: Speech

Purpose: To assess corneal biomechanical changes after trabeculectomy, phaco-trabeculectomy, Ahmed glaucoma valve implantation and phacoemulsification.
Methods: In a prospective study on 65 glaucomatous eyes of 65 subjects who underwent trabeculectomy, phaco-trabeculectomy or Ahmed glaucoma valve (AGV) implantation and 24 non-glaucomatous eyes of 24 subjects who underwent phacoemulsification, ocular response analyzer (ORA) was done before, one month, and three months after operation. The changes in corneal hysteresis (CH) and corneal resistance factor (CRF) were analyzed. Patients with postoperative intraocular pressure (IOP) › 21mmHg and ‹ 5 mmHg and patients with surgical complications were excluded.
Results: Corneal hysteresis was less than normal in glaucomatous patients .It was 5.22 mmHg in AGV group, 5.37mmHg in trabeculectomy group, 5.36mmHg in phaco_trabeculectomy group and 8.13 mmHg in phacoemulsification group. Corneal hysteresis increased significantly in groups with IOP changes › -10 mmHg. The mean CH change was +2.30 mmHg after AGV, +2.16 mmHg after trabeculectomy, and +2.29 mmHg after phaco-trabeculectomy groups ( all ps ≤0.001); and +0.11 mmHg after phacoemulsification group (p‹ 0.001). Corneal resistance factor Changes were not significant in all groups.
Conclusion: Corneal hysteresis is less than normal in glaucomatous patients and it will increase significantly after glaucoma surgeries. This change might have significant effect on routine IOP measurements after glaucoma surgeries.