Corneal biomechanical properties in different anterior chamber angle of glaucoma / 中华实验眼科杂志

Background Recent studies have demonstrated that glaucoma progression had great relationship with corneal biomechanical properties.However,there are not enough studies about corneal biomechanical properties in different types of glaucoma.Objective This study was to evaluate the corneal biomechanical properties in chronic primary angle-closure glaucoma (CPACG) and primary open angle glaucoma (POAG).Methods Prospective observational study was adopted.Sixty-eight cases (68 eyes) with CPACG and 69 POAG patients (69 eyes) from Zhongshan Ophthalmic Center were investigated by a novel technique named Corvis-ST which can measure corneal deformation.The Cronbach's αt coefficient and intraclass correlation coefficient (ICC) were used to evaluate the repeatability of the parameters from Corvis-ST.The differences of corneal biomechanical properties between POAG and CPACG were evaluated by independent-samples t test.Multiple regression analysis was used to assess the association between parameters of deformation response and clinical factors.This study protocol was approved by Ethic Committee of Zhongshan Ophthalmic Center and complied with Helsinki Declaration.Written informed consent was obtained from each patient prior to any medical examination.Results There were no statistic differences about age,sex and intraocular pressure (IOP) between CPACG and POAG patients (all at P＞0.05).However,differences existed in the number of anti-glaucoma medications (t =-2.388,P =0.020).Measurements of central corneal thickness (CCT),deformation amplitude (DA),and peak distance (PD) demonstrated excellent repeatability (ICC≥ 0.8).There were no statistic differences about CCT,first applanation time/length/velocity (A1 T,A1 L,A1V),second applanation time/length/velocity (A2T,A2L,A2V),DA between CPACG and POAG patients (all at P＞ 0.05).The highest concavity time was shorter (t =2.920,P =0.005),PD was bigger (t =-2.453,P =0.017),and central curvature radius (CCR) was smaller (t =1.997,P =0.050) in POAG than those in the CPACG patients.DA,A1V,A2T and PD were negatively associated with IOP (r =-0.709,-0.531,-0.645,-0.554;all at P＜0.001).However,A1T and A2V were positively associated with IOP (r=0.744,0.546;both at P＜0.001).And CCR was positively associated with CCT (r =0.181,P =0.039).Conclusions It is useable to evaluate corneal biomechanical properties of glaucoma by Corvis ST.Under the same level of IOP,the corneal concavity of POAG is easier than that of CPACG,which indicates that cornea in POAG patients is more deformable.

Effectiveness of diode laser trans-scleral cyclophotocoagulation in patients following silicone oil-induced ocular hypertension in Chinese eyes.

We evaluated the effectiveness of diode laser trans-scleral cyclophotocoagulation (TSCPC) on intraocular pressure (IOP) in nine patients having raised IOP following use of silicone oil (SO) for retinal detachment (RD) surgery in a retrospective observational case series. Diode laser TSCPC was applied at a power setting of 1.75 to 2.5 watts, for two sec with a maximum of 30 applications. The patients were followed up for 40 to 312 weeks. The mean pre-laser IOP was 32.06 mm Hg (SD 7.32). The mean post-laser IOP at one month, three months and six months was 17.89 mm Hg (SD 8.23), 21.89 mm Hg (SD 8.16) and 21.67 mm Hg (SD 7.55) respectively. The final IOP (at the last follow-up) was 19.56 mm Hg (SD 7.85) (P=0.021). Seven of them had undergone SO removal. In our observation, effectiveness of TSCPC in long-term control of SO-induced ocular hypertension was limited as compared to short-term control of IOP.

Calculating graft size and position in rotational corneal autografting: a simplified approach.

In eyes with eccentric corneal opacities partially involving the pupillary area, using a rotational corneal autograft, can help restore vision without the immunological complications associated with allografts. In this report, we describe a simple intraoperative method for determining trephine size and placement for rotational corneal autografting. This surgical approach helps in the planning and execution of rotational corneal autografting, to obtain good outcomes.

Intracameral lidocaine in trabeculectomy. A preliminary safety and efficacy study.

PURPOSE: To study the safety and efficacy of intracameral lidocaine as anaesthesia in trabeculectomy for primary open-angle glaucoma. METHODS: Trabeculectomy under intracameral anaesthesia using 1% preservative-free lidocaine was performed in 10 patients with primary open-angle glaucoma. Intraoperative pain score, postoperative intraocular pressure (IOP) and endothelial cell count at 3 months were recorded. RESULTS: The mean pain score was 1.70 +/- 1.34. The mean IOP was lowered from 24.60 +/- 8.28 mmHg preoperatively to 14.1 +/- 3.11 mm Hg postoperatively. There was no significant decrease in the mean endothelial cell count 3 months after the surgery (P = 0.375). CONCLUSION: Intracameral lidocaine may be a safe and effective alternative anaesthesia method in trabeculectomy for uncomplicated primary open-angle glaucoma.

Argon laser suture lysis using Ritch lens following cataract surgery.

Argon laser suture lysis using the Ritch lens provides a safe and effective means for correction of post--ECCE suture--induced astigmatism.