Phacoemulsification in Patients with Ahmed Glaucoma Valve Implant

PURPOSE: To investigate the effects of phacoemulsification in glaucomatous eyes with a functioning Ahmed glaucoma valve insertion. METHODS: This retrospective analysis followed 28 eyes from 26 patients with a functioning Ahmed glaucoma valve who had clear corneal phacoemulsification from December 1999 to February 2006. Intraocular pressure (IOP), best corrected visual acuity (BCVA), number of glaucoma medications and additional glaucoma surgeries were measured. RESULTS: The mean IOP before phacoemulsification was 17.4 mmHg +/- 5.8 (SD). Postoperative IOP was 13.6 +/- 4.4 mmHg, 13.7 +/- 4.0 mmHg, 14.1 +/- 4.0 mmHg and 15.4 +/- 3.8 mmHg at 1, 2, 6, and 12 months, respectively. The change in the number of glaucoma medications significantly changed at 1 month (p0.05) postoperatively. The IOP significantly changed at 1 week, 1 month, 2 months, and 6 months (p0.05) postoperatively. No eyes required additional surgery. BCVA improved in 23 eyes; the mean improvement was 3.7 +/- 2.9 Snellen lines at 2 months postoperatively. CONCLUSIONS: Phacoemulsification in glaucomatous eyes with a functioning Ahmed glaucoma valve improved BCVA and maintained control of IOP.

Neovascular Glaucoma: Diode Laser Trans-Scleral Cyclophotocoaculation Versus Ahmed Glaucoma Valve Implant

PURPOSE: To retrospectively study the clinical outcomes of diode laser trans-scleral cyclophotocoagulation and Ahmed glaucoma valve implant in eyes with neovascular glaucoma. METHODS: We reviewed the medical records of patients who had undergone diode laser trans-scleral cyclophotocoagulation (group 1) and Ahmed glaucoma valve implant (group 2) with a follow-up period of 6 months or longer. The treatments were carried out to control high intraocular pressure (IOP) and ocular pain in the patients with visual acuity less than hand motions. RESULTS: Group 2 had a significantly lower IOP during the first postoperative month. The cumulative probability of success was higher in group 2 than group 1 throughout the follow-up period. The postoperative complications in most cases were transient and improved with conservative management in both groups. However, 3 cases in group 1 required evisceration secondary to phthisis. Subjective relief of ocular pain was higher in group 2. CONCLUSIONS: The Ahmed glaucoma valve implant group showed a higher success rate and fewer serious complications than the diode laser trans-scleral cyclophotocoagulation group in patients with high IOP and ocular pain with poor visual acuity. Diode laser trans-scleral cyclophotocoagulation may be considered in patients with poor general health.

Comparison of Short-term Surgical Outcomes of Ahmed Glaucoma Valve Implant between 96 mm2 and 184 mm2 of the Surface Area

PURPOSE: To compare the short-term surgical outcomes of Ahmed glaucoma valve implant with a surface area between 96 mm2 and 184 mm2. METHODS: The outcomes of thirteen eyes of 13 patients with refractory glaucoma who had undergone 96 mm2-sized Ahmed glaucoma valve implantation were compared with those of 13 eyes of 13 patients with 184 mm2-sized Ahmed glaucoma valve implantation. RESULTS: Average age and preoperative intraocular pressure (IOP) were statistically indistinguishable between the two groups (p=0.54 and 0.40, respectively). Average follow-up period and final IOP were also statistically similar (p=0.15 and 1.00, respectively). Comparing the overall IOPs and the numbers of antiglaucoma medications, the IOP of postoperative day 1 with the 184 mm2-group was only relatively lower (p=0.07). The 2-year success rates were 18.0% for the 96 mm2-group and 69.2% for the 184 mm2-group (Ed-there is no respective comparison here) with Kaplan-Meier survival analysis (p=0.0018). The rates of complications and re-operation were similar between the two groups. CONCLUSIONS: The average postoperative IOPs were not statistically different between the two groups. However, the success rate was better in the 184 mm2-group than in the 96 mm2-group.

The Effectiveness of Surface Area Extension with Pericardial Membrane in Ahmed Glaucoma Valve Implant Surgery

PURPOSE: To assess the effect of surface area extension with pericardial membrane on the hypertensive phase and surgical success in Ahmed glaucoma valve implant surgery. METHODS: This prospective study included 10 eyes of 8 patients who underwent Ahmed glaucoma valve implant surgery with pericardial membrane(Preclude(R)) which were designed to have surface area of 300 mm2 (Group I) and 10 eyes of 9 patients who underwent Ahmed glaucoma valve implant surgery without surface area extension (Group II). The mean follow-up was 11.5+/-5.1 months and 14.9+/-4.3 months for the group I and group II, respectively. RESULTS: Two eyes (20%) exhibited hypertensive phase in group I and 8 eyes (80%) in group II (p=0.007). The complete success rate was 90% in group I and 70% in group II (p=0.291). The mean number of preoperative antiglaucoma medication was 2.4+/-0.5 and 1.9+/-0.3 for the group I and group II, respectively, and the mean number of postoperative antiglaucoma medication was 0.1+/-0.3 and 0.4+/-0.7 for the group I and group II, respectively. CONCLUSIONS: Surface area extension with pericardial membrane (Preclude(R)) in Ahmed glaucoma valve implant surgery affords statistically significantly lower hypertensive phase rate and trends toward high complete success rate and less number of postoperative antiglaucoma medications.

The Effect of a 5-0 Prolene Ligation Around the Ahmed Glaucoma Valve Tube on the Postoperative Hypotony

PURPOSE: To evaluate the efficacy and safety of 5-0 prolene ligation around the Ahmed glaucoma valve tube to prevent the postoperative hypotony and flat anterior chamber. METHODS: Medical records of twenty one eyes of 20 patients those had got Ahmed valve implant surgery with temporary ligation of the tube with 5-0 prolene were retrospectively evaluated for efficacy of the pressure control and complications before and after the remove of the ligation suture. RESULTS: Preoperative intraocular pressure(IOP) was 46.1+/-9.1 mmHg. The ligation suture was removed at 2.8+/-1.5 postoperative day. Postoperative IOP before the removal of the suture was 24.8+/-15.4 mmHg at the day of removal. After removal of the ligation suture, the IOP decreased to 15.6+/-5.9 mmHg and 12.2+/-4.2 mmHg at one day and 12 weeks after the removal respectively. Complications before the removal of the ligation suture were mild hyphema and corneal edema, developed in one eye each. After the removal, shallow anterior chamber and choroidal detachment was developed in one eye. CONCLUSIONS: Although the efficacy of the temporary ligation of the tube in Ahmed valve implant surgery in controlling the IOP was similar to that of conventional Ahmed valve implant surgery without ligation, the early postoperative complications associated with the overfiltration appeared to be less frequent than conventional Ahmed valve implant surgery.

A Clinical Study of the Ahmed valve Implant in Refractory Glaucoma

PURPOSE: We retrospectively studied the efficacy, safety, and clinical outcomes of the Ahmed Glaucoma Valve implant in refractory glaucoma. METHODS: We studied 58 eyes(49 patients) with an average follow up period of 21.2+/-17.7 months. Success was defined as an intraocular pressure of less than 22 mmHg and greater than 4mmHg for 3 months or longer regardless of glaucoma medication. RESULTS: The success rates which were controlled valve failure at 12 months and 24 months postoperatively were 83.1% and 64.5%, respectively. The reduction of intraocular pressure and number of medications were both statistically and clinically significant(P<0.0001). Early complication was immediate hypotony in 6 eyes(10.3%). Late complications were bullous keratopathy in 3 eyes(5.3%) and conjunctival fibrosis in 7eyes (17.2%). CONCLUSION: Well controlled intraocular pressure and prevented hypotony were observed in Ahmed Glaucoma Valve. Randomized, prospective studies are needed to compare the clinical results of the Ahmed Glaucoma Valve implant with that of other drainage devices.

Ahmed Glaucoma Valve Implant for Neovascular Glaucoma

We studied retrospectively the results of the Ahmed glaucoma valve implant surgery in 20 eyes with neovascular glaucoma. All cases were failed with medical or surgical glaucoma interventions. Mean follow-up period was 15.1 +/-14.9 months (3~56 months). The criteria for success included a postoperative intraocular pressure (IOP) of less than or equal to 21 mmHg and greater than or equal to 6 mmHg, and no additional glaucoma therapy or devastating visual complications. Mean IOP was significantly reduced from pre- operative 36.9 +/-5.2 mmHg to 17.6 +/-8.7 mmHg at the last visit. In respect with IOP control,success rate was 80%at final follow-up.The causes of failure were loss of light perception in 3 eyes (25%), inadequate IOP control in 2 eyes (10%), tube removal due to malfunction in 1 eye (5%). Complete success rate was 70%at a final follow-up.Complication included hyphema in 15 eyes,hypotony in 7 eyes, fibrous membrane formation and anterior synechiae in 3 eyes, tube obstruction in 2 eyes, flat anterior chamber in 1 eye, corneal decompensation in 1 eye, tube malposition in 1 eye, temporary choroidal detachment in 1 eye. These results indicate that Ahmed glaucoma valve implant for neovascular glaucoma can be a good successful IOP control device and comparable to the other drainage device.

Combined Pars Plana Vitrectomy and Ahmed Implantation for Refractory Glaucoma

Eyes with neovascular glaucoma often times present with vitreous hemorrhage which makes subsequent panretinal photocoagulation difficult to impossible. These eyes can benefit from pars plana vitrectomy combined with glaucoma shunt procedure. Other candidates are those refractory galucomatous eyes with severe vitreoretinal diseases that require surgical intervention. We performed standard pars plana vitrectomies in combination with Ahmed Glaucoma Valve implant and analyzed the surgical outcome in 11 eyes of 11 patiens with severe refractory galucoma. With the surgical success defined as an achievement of intraocular pressure(IOP) less or equal to 21 mmHg with anatomical reattatchment of retina, nine eyes(81.8%) became qualified in the success group. Complications included hyphema and/or severe fibrinous reaction (3 eyes), temporary IOP increase (3 eyes), recurrent vitreous hemorrhage (1 eye) and loss of light perception (1 eye). No eye showed postoperative hypotony, choroidal effusion or hemorrhage. In conclusion, in those eyes with refractory glaucoma accompanied with severe vitreoretinal disease that do not respond to the conventional IOP lowering procedures, combined pars plana vitrectomy with Ahmed Glaucoma Valve implantation may serve as a useful surgical alternative.

A Case of Total Vitrectomy in Aphakic Refractory Glaucoma with Prior Keratoplasty after Ahmed Glaucoma Valve Implantation

Aqueous drainage devices have been used to treat refractory glaucoma with poor prognosis, but it has been described with valved implants and non-valved implants that their complications are hypotony, shallow anterior chamber, hyphema, suprachoroidal hemorrhage, endothelial touch by tube and the blockage of tube with fibrin, iris or vitreous. We used the Ahmed galucoma vlave implant to control the intraocular pressure in the aphakic eye with prior penetrating keratoplasty. Although the blockage of tube with vitreous was developed in first postoperative day, we successfully removed that blockage by total vitrectomy.

Clinical Results of Ahmed Glaucoma Implantation in Refractory Glaucoma

24 eyes of 20 patients with increased intraocular pressure(IOP) or glaucoma that were not medically controlled or those who failed with previous glaucoma surgeries underwent Ahmed glaucoma valve implantation with intraoperative mitomycin C application. Mean follow-up period was 4.5 months (2-9 months) and mean preoperative IOP was 38.0 +/- 11.5mmHg. Mean IOP at last visit was 16.5 +/- 6.2mmHg and it was significantly lower compared to preoperative IOP (p<0.0001). One eye (4.2%) showed IOP less than 5mmHg at first postoperative day. When surgical success was defined as IOP less than 22mmHg and greater than 4 mmHg for 2 months or longer, IOP lowered by at least 20% from preoperative values (in eyes with preoperative IOP less than 22mmHg), and no additional glaucoma surgery or visually devastating complications, cumulative probability of success at 7 months was 69.1%. Qualified success (defined as lOP less than 22mmHg and greater than 4mmHg at last visit) rate was 83.3%. Complete success (IOP controlled as above without medication) rate was 66.7%. The complications included temporary shallow anterior chamber in 3 eyes, choroidal detachment in 3 eyes, fibrous membrane formation in anterior chamber in 3 eyes, hyphema in 2 eyes, tube malposition in 1 eye, corneal decompensation in 1 eye and tube blockage in 1 eye. This study suggests that Ahmed glaucoma implant provides good IOP control without significant postoperative complications including immediate postoperative period, and its success rate is comparable to the other seton implants.