Long-term success of ahmed glaucoma valve in refractory glaucoma

AIM:To evaluate the long-term results and complications of ahmed glaucoma valve (AGV) implantation in refractory glaucoma.· METHODS:A retrospective review of 13 patients (13 eyes) with refractory glaucoma who underwent AGV implantation and had a minimum follow-up of 18 months was performed.All patients underwent a complete ophthalmologic examination and intraocular pressure (IOP) measurement before surgery and at 1 month,3 months,6 months,1 year after surgery and yearly afterwards.Complications and the number of antiglaucoma medications needed were recorded.· RESULTS:Mean age was 27.3±16.0 years.All eyes (100%) had at least one prior incisional surgery.Mean follow-up was 61.3±30.8 months.IOP was reduced from a mean of 35.0±7.0mmHg to 18.2±7.9mmHg at 12 months and to 17.0±4.1mmHg at 96 months (P <0.05) with a lower number of medications from baseline,76.9% patients required additional procedures to achieve the success criteria set by previously published series.The most common complications were encapculated cyst formation in eight eyes (61.5%) and tube exposure in four eyes (30.8%).· CONCLUSION:Encapsulated cyst formation was the most common complication which hindered succesful IOP control after AGV implant insertion for refractory glaucoma.Despite cyst excision with anti-fibrotic agents,successful IOP reduction was not achieved in 76.9% of the patients without antiglaucoma medication.

Intravitreal bevacizumab and Ahmed glaucoma valve implantation in patients with neovascular glaucoma

AIM:To explore the efficacy of preoperative intravitreal bevacizumab(IVB) injection combined with Ahmed glaucoma valve(AGV) implantation in the treatment of neovascular glaucoma(NVG).METHODS:This retrospective study included 35 eyes from 35 patients who underwent preoperative IVB and AGV implantation for treatment of NVG. Findings such as intraocular pressure(IOP) number of anti-glaucoma medications, visual acuity(VA), surgical success rates,and complications were recorded.RESULTS:AfterAGVimplantation,IOPwas18.2±4.0mmHg,15.5±3.3 mm Hg and 9.8±2.6 mm Hg at 6, 12 and 36 mo,significantly decreased compared with pre-IOP(P 【0.01).The number of anti-glaucoma medications was 0.9 ±0.5,0.8 ±0.9 and 0.8 ±0.6 at 6, 12 and 36 mo, significantly decreased compared to pre-treatment(P 【0.01). At last visit, there were 19 eyes with stable VA, 4 with VA improvement, 12 with diminished VA and 3 with complete loss light perception. There were 7 cases that failed during 3-year fellow up period. Cumulative probabilities of valve survival by Kaplan-Meier analysis were 82.9%,74.1% and 71.0% at 12, 24 and 36 mo, respectively. Cox stepwise regression analysis found that the survival time was significant associated with the pre-visual acuity 【2/400(P 【0.05). Post-operative complications occurred in 8eyes, of which hyphema presented in 2 eyes, choroidal effusion in 2 eyes.CONCLUSION:The procedure of preoperative IVB andAGV implantation should be one of treatments for NVG because of its safety and effectiveness.

Trabeculectomy with Ex-PRESS implant versus Ahmed glaucoma valve implantation-a comparative study

AIM：To compare the surgical outcomes of trabeculectomy with Ex-PRESS implant and Ahmed glaucoma valve（AGV） implantation. METHODS： Patients who underwent trabeculectomy with Ex-PRESS implants or AGV implantation separately were included in this retrospective chart review.Main outcome measures were surgical failure and complications.Failure was defined as intraocular pressure（IOP） 〉21 mm Hg or 〈5 mm Hg on two consecutive visits after 3mo,reoperation for glaucoma,or loss of light perception.Eyes that had not failed were considered as complete success if they did not required supplemental medical therapy.RESULTS： A total of 64 eyes from 57 patients were included： 31 eyes in the Ex-PRESS group and 33 eyes in the AGV group.The mean follow-up time was 2.6 ±1.1y and 3.3±1.6y,respectively.Patients in the AGV group had significantly higher baseline mean IOP（P =0.005）,lower baseline mean visual acuity（VA）（P =0.02）,and higher proportion of patients with history of previous trabeculectomy（P 〈0.0001）.Crude failure rates were 16.1%,n =5/31 in the Ex-PRESS group and 24.2%,n =8/33 in the AGV group.The cumulative proportion of failure was similar between the groups,P =0.696.The proportion of eyes that experienced postoperative complications was32.3% in the Ex-PRESS group and 60.1% in the AGV group（P =0.0229）.CONCLUSION： Trabeculectomy with Ex-PRESS implant and AGV implantation had comparable failure rates.The AGV group had more post-operative complications,but also included more complex cases with higher baselinemean IOP,worse baseline mean VA,and more previous glaucoma surgeries.Therefore,the results are limited to the cohort included in this study.

Long-term results of Ahmed glaucoma valve implantation in Egyptian population

AIM： To evaluate the long-term results and complications of Ahmed glaucoma valve （AGV） implantation in a cohort of Egyptian patients. METHODS： A retrospective study of 124 eyes of 99 patients with refractory glaucoma who underwent AGV implantation and had a minimum follow-up of 5y was performed. All patients underwent complete ophthalmic examination and intraocular pressure （lOP） measurement before surgery and at ld, weekly for the 1st month, 3, 6mo, and ly after surgery and yearly afterward for 5y. lOP was measured by Goldmann applanation tonometry and/or Tono-Pen. Complications and the number of anti-glaucoma medications needed were recorded. Success was defined as lOP less than 21 mm Hg with or without anti-glaucoma medication and without additional glaucoma surgery. RESULTS： Mean age was 23.1±19.9y. All eyes had at least one prior glaucoma surgery, lOP was reduced from a mean of 37.2±6.8 to 19.2±5.2 mm Hg after 5y follow-up with a reduced number of medications from 2.64±0.59 to 1.81±0.4. Complete and qualified success rates were 31.5% and 46.0% respectively at the end of follow-up. The most common complications were encapsulated cyst formation in 51 eyes （41.1%）, complicated cataract in 9 eyes （7.25%）, recessed tube in 8 eyes （6.45%）, tube exposure in 6 eyes （4.8%） and corneal touch in 6 eyes （4.8%）. Other complications included extruded AGV, endophthalmitis and persistent hypotony. Each of them was recorded in only 2 eyes （1.6%）. ~ CONCLUSION： Although refractory glaucoma is a difficult problem to manage, AGV is effective and relatively safe procedure in treating refractory glaucoma in Egyptian patients with long-term follow-up. Encapsulated cyst formation was the most common complication, which limits successful lOP control after AGV implantation. However, effective complications management can improve the rate of success.

Clinical efficacy of Ahmed glaucoma valve implantation combined with 23-gauge vitrectomy for medically uncontrolled neovascular glaucoma with proliferative diabetic retinopathy

AIM:To describe the clinical results of combined Ahmed valve implantation and 23-gauge vitrectomy for medically uncontrolled neovascular glaucoma(NVG)secondary to proliferative diabetic retinopathy(PDR).METHODS:The medical records of medically uncontrolled NVG patients with PDR who underwent Ahmed valve implantation and 23-gauge vitrectomy between March 2016 and December 2018 were reviewed.Enrolled patients had at least 6-month follow-up.Panretinal photocoagulation(PRP),anti-vascular endothelial growth factor,surgery and medication history were documented.RESULTS:Eleven eyes of 11 patients were included in our study.The visual acuity improved in 8 eyes and remained unchanged in 3 eyes.The preoperative intraocular pressure(IOP)was significantly decreased at the last follow-up(48.8±4.3 to 17.0±1.5 mm Hg,P<0.001).All eyes needed three topical anti-glaucomatous medications before surgery,but the number was significantly reduced to 0.72±0.19 at the last visit(P<0.001).Four eyes had choroidal detachment and 3 eyes had minor hyphemia,all of which gradually resolved without treatments in one week.CONCLUSION:Ahmed glaucoma valve implantation combined with 23-gauge vitrectomy might be a safe and alternative treatment for NVG with PDR.

Efficacy and safety of intravitreal ranibizumab with panretinal photocoagulation followed by trabeculectomy compared with Ahmed glaucoma valve implantation in neovascular glaucoma

AIM：To evaluate the efficacy and safety of intravitreal ranibizumab（IVR）with panretinal photocoagulation（PRP）followed by trabeculectomy compared with Ahmed glaucoma valve（AGV）implantation in neovascular glaucoma（NVG）.METHODS：This was a retrospective comparative study.We reviewed the cases of a total of 45 eyes from 45 NVG patients among which 23 eyes underwent AGV implantation and the other 22 underwent trabeculectomy. The causes of neovascular glaucoma included：diabetic retinopathy（25 eyes）,and retinal vein occlusion（20 eyes）.All patients received preoperative IVR combined with postoperative PRP. The mean best-corrected visual acuities（BCVA）were converted to the logarithms of the minimum angle of resolution（log MAR）for the statisitical analyses.Intraocular pressure（IOP）,the log MAR BCVA and surgical complications were evaluated before and after surgery.The follow-up period was 12 mo.RESULTS：A total of 39 cases showed complete regression of iris neovascularization at 7d after injection,and 6 cases showed a small amount of residual iris neovascularization. The success rates were 81.8% and 82.6% at 12 mo after trabeculectomy and AGV implantation,respectively. In the trabeculectomy group,the log MAR BCVA improved at the last follow-up in 14 eyes,remained stable in 6 eyes and decreased in 2 eyes. In 4 cases,slight hyphemas developed after trabeculectomy. A shallow anterior chamber developed in 2 cases and 2 vitreous hemorrhages. In the AGV group,the log MAR BCVA improved in 14 eyes,remained stable in 5 eyes and decreased in 4 eyes. Slight hyphemas developed in 3 cases,and a shallow anterior chamber in 3 cases. The mean postoperative IOP was significantly lower in both groups after surgery（F=545.468,P〈0.05）,and the mean postoperative log MAR BCVA was also significantly improved（F=10.964,P〈0.05）with no significant difference between two groups.CONCLUSION：It is safe and effective to treat NVG with this combined procedure,and we found similar results after IVR＋AGV implantation＋PRP and IVR＋trabeculectomy＋PRP in eyes with NVG.

Comparison of the efficacy and safety of ultrasonic cycloplasty vs valve implantation and anti-VEGF for the treatment of fundus disease-related neovascular glaucoma

·AIM: To compare the clinical efficacy and safety of ultrasonic cycloplasty(UCP) vs Ahmed glaucoma drainage valve implantation(ADV) in addition to intravitreal antivascular endothelial growth factor(VEGF) for treatment of fundus disease-related neovascular glaucoma(NVG).·METHODS: A total of 43 patients(45 eyes) with NVG secondary to fundus diseases underwent anti-VEGF combined with UCP or ADV from August 2020 to March 2022 were enrolled in this retrospective cohort study. Of them, 14 patients(15 eyes) were treated with both UCP and anti-VEGF as the UCP group and 29 patients(30 eyes) treated with both ADV and anti-VEGF as the ADV group. The success of the treatment was defined as intraocular pressure(IOP) between 11-20 mm Hg with or without using IOP-lowering drugs. IOP measurement, IOP lowering drugs at baseline and follow-ups period and complications were recorded.·RESULTS: The average age was 63.03±9.95 and 52.27±12.89y in ADV and UCP groups, respectively(P=1.947). The fundus pathology included proliferative diabetic retinopathy in 42 eyes and retinal vein occlusion in 3 eyes. All eyes in both groups achieved successful treatment at 3mo. While the success rate was 90.0%(27/30) in the ADV group and 86.7%(13/15) in the UCP group at the last follow-up of 6mo(P>0.05). IOP was significantly lower with reduction of drug use than the baseline in both groups(both P<0.05). And the ADV group needed fewer anti-glaucoma drops than the UCP group from 1d to 3mo. The comfort scores of patients in the ADV group were significantly lower than those in the UCP group in the first week after the operation(P<0.05).·CONCLUSION: UCP is an alternative to the ADV with the same efficacy but non-invasive for the treatment of NVG.

Adjunctive with versus without intravitreal bevacizumab injection before Ahmed glaucoma valve implantation in the treatment of neovascular glaucoma

Background Neovascular glaucoma （NVG） is a refractory disease which is difficult to manage. This study aimed at evaluating the efficacy and safety of adjunctive intravitreal bevacizumab （IVB） injection in conjunction with Ahmed glaucoma valve implantation （AGVI） in the management of NVG. Methods This was a retrospective study of patients with NVG in whom AGVI was performed between October 2008 and May 2012. The sample was divided into two groups according to the pretreatment： with adjunctive IVB injection （the IVB group, n=25 eyes） and without adjunctive IVB injection （the control group, n=28 eyes）. The surgical success rate, number of antiglaucoma medications used, best-corrected visual acuity （BCVA）, postoperative complications, regression, and recurrence of iris neovascularization （NVI） were analyzed between the groups. Results The surgical outcomes of the two groups were compared. The complete success rates in the IVB and control groups were 84.0% and 64.3% at 12 months and 80.0% and 53.6% at 18 months, respectively. There was a significant difference between the two groups （P=0.041）. Mean postoperative intraocular pressures, mean number of postoperative antiglaucoma medications, and BCVA were not significant between the two groups. The NVI in 22 （88.0%） eyes had completely regressed within 2-8 days after IVB. However, NVI recurred in 10 eyes （40.0%） 2-9 months later after IVB. The IVB group had only 1 case （4.0%） of hyphema out of 25 eyes, while there were 8 （28.6%） cases of hyphema out of 28 eyes in the control group （P=0.026）.Conclusions This study showed that preoperative IVB injection reduced NVI remarkably, decreased hyphema, and led to higher surgical success rates. Pre-operative IVB injection may be an effective adjunct to AGVI in the management of NVG.

A prospective comparative study on neovascular glaucoma and non- neovascular refractory glaucoma following Ahmed glaucoma valve implantation

Background Neovascular glaucoma is a refractory disease, and difficult to manage. The aim of this study was to evaluate the clinical outcomes of Ahmed glaucoma valve implantation （AGVI） in neovascular glaucoma （NVG） and non- NVG patients. Methods This prospective, non-randomized study included 55 eyes of 55 patients with refractory glaucoma; 27 had NVG （NVG group） and 28 had non-NVG （non-NVG group）. All of the patients underwent AGVI. The NVG group was adjunctively injected with intravitreal ranibizumab/bevacizumab （IVR/IVB） before AGVI. Intraocular pressure （lOP） was the primary outcome measure in this study. Surgical success rate, number of antiglaucoma medications used, best corrected visual acuity （BCVA）, and postoperative complications were analyzed between the groups. Results All of the patients completed the study （follow-up of 12 months）. Kaplan-Meier survival curve analysis indicated that the qualified success rates in the NVG and non-NVG groups at 12 months were 70.5% and 92.9%, respectively; this difference was significant （P=-0.036）. The complete success rates in the NVG and non-NVG groups at 12 months were 66.7% and 89.3%, respectively （P=0.049）. Compared with preoperative examinations, the postoperative mean lOP and use of medications were significantly lower at all follow-up time points in both groups （all P 〈0.05）. There were significant differences in BCVA between the two groups at the 12-month follow-up （X2=9.86, P=0.020）. Cox proportional hazards regression showed NVG as a risk factor for surgical failure （RR=15.08, P=0.033）. Postoperative complications were similar between the two groups. Conclusions AGVI is a safe and effective procedure in refractory glaucoma, but the success rate of surgery was related to the type of refractory glaucoma. The complete and qualified success rates of NVG patient adjunctive anti-vascular endothelial growth factor treatment are still lower than those of non-NVG patients.

Ahmed valve implantation for neovascular glaucoma after 23-gauge vitrectomy in eyes with proliferative diabetic retinopathy

·AIM: To report on the outcome of Ahmed glaucoma valve (AGV) implantation for the management of neovascular glaucoma (NVG) after 23 -gauge vitrectomy for proliferative diabetic retinopathy (PDR). ·METHODS: Twelve medically uncontrolled NVG with earlier 23 -gauge vitrectomy for PDR underwent AGV implantation. The control of intraocular pressure (IOP), preoperative and postoperative best -corrected visual acuity, the development of intraoperative and postoperative complications were evaluated during the follow-up. ·RESULTS: The mean follow-up was 15.4±4.3 months (9-23 months). Mean preoperative IOP was 49.4±5.1mmHg and mean postoperative IOP at the last visit was 17.5 ± 1.6mmHg. The control of IOP was achieved at the final follow -up visits in all patients, however, 8 of 12 patients still needed anti-glaucoma medication (mean number of medications, 0.8±0.7). The visual acuity improved in nine eyes, and the visual acuity unchanged in three eyes at the final follow -up visits. The complications that occurred were minor hyphema in three eyes, choroid detachment in two eyes, and the minor hyphema and choroid detachments were reabsorbed without any surgical intervention. ·CONCLUSION: AGV implantation is a safe and effective procedure that enables successful IOP control and vision preservation in the NVG patients with the history of earlier 23-gauge vitrectomy for PDR.·

Disorder of blood-aqueous barrier following Ahmed Glaucoma Valve implantation

Background Ahmed Glaucoma Valve implantation （AGVI） is blood-aqueous barrier （BAB） has been noted after some surgica BAB disruption afterAGVl. used to treat refractory glaucoma. Breakdown of the techniques. The current study was designed to assess Methods Anterior chamber protein content was measured by the laser flare cell photometry in 22 eyes of 22 patients with refractory glaucoma before AGVI and at each postoperative visit up to 1 month. Results Before AGVI the mean aqueous flare values in all eyes were （15.17＋9.84） photon counts/ms. After AGVI, the values significantly increased at day 1, day 3, and week I compared to those before AGVI （all P 〈0.05） with a peak at day 3. They returned to pre-operative levels at week 2, and were lower than preoperative level at month 1. Eyes with previous intraocular surgery history had greater aqueous flare values than those without previous intraocular surgery history, but there were no significant differences at all time points postoperatively （all P 〉0.05）. Furthermore, eyes with shallow anterior chambers had greater aqueous flare values at day 3 and week 1 （all P 〈0.05）. When comparing eyes with other refractory glaucoma conditions, neovascular glaucoma combined with intravitreal bevacizumab injection resulted in lower aqueous flare values after AGVI, but no significant differences were observed at all time points, postoperatively （all P 〉0.05）. Conclusions The BAB was impaired and inflammation was present in the anterior chamber in refractory glaucomatous eyes following AGVI. However, such conditions were resolved within 1 month postoperatively. Intravitreal bevacizumab treatment in neovascular glaucoma eyes before AGVI may prevent BAB breakdown.

Outcomes of Ahmed valve surgery for refractory glaucoma in Dhahran, Saudi Arabia

AIM: To evaluate the outcomes of Ahmed glaucoma valve(AGV) implantation surgery for refractory glaucoma.METHODS: This one-armed historical cohort study was conducted in 2011. Refractory glaucoma was defined as eyes with an intraocular pressure(IOP) greater than21 mm Hg with maximally tolerated glaucoma medications, failed surgeries, or both. For all eyes with refractory glaucoma that underwent AGV implantation,data were collected on IOP, the best corrected visual acuity(BCVA) and glaucoma medications preoperatively and 4, 6, 12, 24 and 56 wk postoperatively. Logarithm values of IOP were calculated and compared. RESULTS: The study group was comprised of 30patients(30 eyes, 16 males and 14 females) with refractory glaucoma. Mean preoperative IOP was 39.3 ±13.8 mm Hg. Postoperative mean IOP was 15.7±7.1 mm Hg,19.6 ±12.8 mm Hg and 13.9 ±14.2 mm Hg at 12, 24 and56 wk respectively. BCVA was ≥6/60 in 11 eyes preoperatively, and five eyes had BCVA ≥6/60 at 56 wk postoperatively. Preoperatively, more than four medications were used to treat glaucoma in 21 eyes. At12 wk postoperatively, no medications were required to control IOP in 20 eyes. At 56 wk postoperatively, at least one medication was required to control IOP in 10 eyes.Over the entire follow up period, four eyes were treated with yttrium aluminium garnet(YAG) laser and 14 eyes required a second surgery. The AGV was removed in four eyes.CONCLUSION: AGV implantation reduced IOP and the number of medications required to control refractory glaucoma. However, there was a higher risk of decreased vision. Long-term follow up and prompt intervention are recommended.

Long-term outcomes of uveitic glaucoma treated with Ahmed valve implant in a series of Chinese patients

AIM： To report long-term outcomes of secondary glaucoma due to uveitis treated with Ahmed glaucoma valve（AGV） implantation in a series of Chinese patients. METHODS： The retrospective study included 67 eyes from 56 patients with uveitic glaucoma who underwent AGV implantation. Success of the treatment was defined as patients achieving intraocular pressure（IOP） levels between 6 and 21 mm Hg with or without additional antiglaucoma medications and/or a minimum of 20% reduction from baseline IOP. The main outcome measurements included IOP, the number of glaucoma medications at 1, 3, 6, 12, 24, 36, 48 and 60 mo after surgery, surgical complications, final best-corrected vision acuity（BCVA）, visual field（VF） and retinal nerve fiber layer（RNFL）.RESULTS： The mean follow-up was 53.3±8.5（range 48 to 60）mo. The cumulative probability of success rate was 98.5%, 95.5%, 89.6%, 83.6%, 76.1%, 70.1%, 65.7% and 61.2% at 1, 3, 6, 12, 24, 36, 48 and 60 mo, respectively. IOP was reduced from a baseline of 30.8±6.8 to 9.9±4.1, 10.1±4.2, 10.9±3.7, 12.9±4.6, 13.8±3.9, 13.2±4.6, 12.3±3.5 and 13.1±3.7 mm Hg at 1, 3, 6, 12, 24, 36, 48 and 60 mo, respectively（P〈0.01）. The number of postoperative glaucoma medications was significantly decreased compared with baseline at all time points during the study period（P〈0.05）. There was no significant difference between preoperative and postoperative BCVA. Remarkable surgical complications were not found after surgery. The VF and RNFL of the patients were stable after the surgery.CONCLUSION： AGV implantation is safe and effect in terms of reducing IOP, decreasing the number of glaucoma medications, and preserving vision for patients with uveitic glaucoma.

Managing high risk glaucoma with the Ahmed valve implant:20 years of experience

AIM： To estimate the efficacy and safety of the Ahmed implant in patients with high risk for failure after glaucoma surgery.METHODS： In 342 eyes of 342 patients with refractory glaucoma, even with application of medical treatment, the Ahmed valve was introduced for intraocular pressure（IOP） control, in the period of the last 20y. The nature of glaucoma was neovascular in 162 eyes, pseudophakic or aphakic in 49 eyes, inflammatory in 29 eyes and non working previous antiglaucomatic surgical interventions in 102 eyes. RESULTS： Follow-up ranged from 18 to 120m o with a mean follow-up of 63.2m o. IOP before the operation decreased from 31.6±10.4 mmHg to 18.3±5.4 mm Hg（no systemic treatment） at the end of follow up period. When we compared the IOP values before the operation using ANOVA showed statistically significant difference（P〈0.001）. The success rate was 85.2% during the first semester, 76.8% at 12 mo and 50.3% at the end of follow up period（18 to 120 mo after implantation）. Success rate was 25.7% in neovascular glaucoma, 63.2% in aphakic glaucoma and 73.8% in non working previous antiglaucomatic surgical interventions. Complications due to the implant were： serous choroidal detachment in 14.8%, blockage of the tube in 2.8%, malposition of the tube in 4.9%, suprachoroidal hemorrhage in 2.1%, cataract progression in 39.6%（phakic eyes）, shallow anterior chamber in 9.2%, hyphaema in 28.9%, exposure of valve in 2.6%, exposure of tube in 9.3%, hypotony in 4.9% and conjunctival fibrosis in 41.5%.CONCLUSION： Despite the fact that Ahmed valve implant had suchlike results as other implants concerning the IOP control, complications rate due to hypotony or over filtration in the first days after the intervention are not that frequent as with other valve implants.

Efficacy of selective laser trabeculoplasty following incisional glaucoma surgery

AIM： To evaluate the efficacy of selective laser trabeculoplasty（SLT） in glaucomatous eyes with previous incisional glaucoma surgery. METHODS： A retrospective cohort of eyes that underwent SLT at a single institution from 2013-2015 were followed for 1 y. Reduction in intraocular pressure（IOP） following SLT was evaluated in eyes with prior trabeculectomy with Ex Press mini shunt（Alcon, Ft Worth, TX, USA）, Ahmed valve（New World Medical, Cucamonga, CA, USA）, or combined phacoemulsification-trabeculectomy. A control group was included with eyes without prior surgery that underwent SLT. Success was defined as 〉20% drop in IOP from pre-SLT baseline. RESULTS： One-hundred and six eyes were included with 53 in both the prior glaucoma surgery（PGS） and no prior glaucoma surgery（NPGS） groups. Mean pre-SLT IOP was 19.2±4.3 and 20.6±6.0 mm Hg for PGS and NPGS groups, respectively（P=0.17）. Both groups produced statistically significant IOP reductions at 1 and 6 mo（P〈0.04）. At 6 mo, mean IOP reduction reached 7.3% and 10.8% for the PGS and NPGS groups, respectively（P=0.42）. Overall, 27.9% and 31.7% of eyes in PGS and NPGS groups met success criteria at 1 y（P=0.70）. In the PGS group, eyes with baseline IOP ≥21 mm Hg had IOP reductions of 18.1%（P〈0.001）, 16.7%（P〈0.01）, and 8.4%（P=0.31） compared to eyes with baseline IOP 〈21 mm Hg who had IOP reductions of 2.3%（P=0.39）, 3.4%（P=0.19）, and 1.1%（P=0.72） at 1, 6 mo, and 1 y, respectively. CONCLUSION： SLT is efficacious in eyes with prior incisional glaucoma surgery and results in similar IOP reductions compared to eyes without PGS. A larger IOP reduction is observed following SLT in eyes with higher pre-SLT IOP.

Review of the Ahmed versus Baerveldt study-5-year treatment outcomes

The results from the tube versus trabeculectomy(TVT)study provided the evidence to support the use of aqueous shunt surgery and its increasing popularity in the world.The Ahmed versus Baerveldt(AVB)study,a randomized controlled study,compared the efficacy and safety between two of the most commonly used glaucoma drainage implants.A significant proportion of the participants had failed trabeculectomy,neovascular or uveitic glaucoma.The 5-year results showed that the cumulative probability for failure is significantly lower for Baerveldt compared to Ahmed group(52.3%vs.40.0%,P=0.039).The most common reason for failure was high intraocular pressure(IOP)but 4%of the Baerveldt group has refractory hypotony.Both surgeries were also effective in reducing dependency on intra-ocular pressure lowering medications but the Baerveldt group is superior in this aspect(median of 1 medication compared to 2 medications for Ahmed group).Both surgeries experienced 60-70%rate of complications but most were self-limiting.The most common long-term complication was corneal decompensation(10%).Overall,the results of the AVB study mirrored the results from the Ahmed Baerveldt Comparison(ABC)study.In conclusion,the 5-year report from the AVB study suggested that the Baerveldt tube is more appropriate for eyes which require much lower IOP such as eyes with advanced glaucoma or in young patients.The Ahmed tube would be more suitable for patients who are at risk of hypotony(such as uveitic and neovascular glaucoma)and those who require immediate IOP lowering after surgery.