ABSTRACT
Objective To evaluate the effectiveness and safety of modified scleral tunnel for the prevention of Ahmed valve tube exposure in Ahmed valve implantation for refractory glaucoma.Methods A retrospective study was conducted in 72 patients with Ahmed glaucoma valve implantation for refractory glaucoma.All the patients were divided into unmodified and modified scleral tunnel group.In the unmodified scleral tunnel group,38 patients (38 eyes) underwent traditional scleral tunnel in Ahmed valve implantation,while in the modified scleral tunnel group,34 patients (34 eyes) received modified scleral tunnel in the procedures.The changes in intraocular pressure and visual acuity after operation were observed,and the incidence of drainage tube exposure and other complications were compared between the two methods after Ahmed valve implantation.The patients were followed up for 6 to 36 months with an average of 18 months.Results The intraocular pressure was (16.30 ±5.73) mmHg (1kPa =7.5 mmHg) in the unmodified scleral tunnel group and (15.80 ± 6.12)mmHg in the modified scleral tunnel group,with no significant difference between the two groups (P ＞ 0.05),but there was significant difference with the preoperative data (48.4 ± 5.79) mmHg (P ＜ 0.01).During the follow-up,conjunctival tube exposure was seen in 3 eyes (7.9％) in the unmodified scleral tunnel group,whereas there was no tube exposure in the modified scleral tunnel group.Conclusion The modified scleral tunnel is capable to prevent conjunctival tube exposure in patients with refractory glaucoma,which is more efficient and safe than traditional scleral tunnel in Ahmed glaucoma valve implantation.