The Ahmed Glaucoma Valve in Refractory Glaucoma: experiences in Indian Eyes

Efficacy of Ahmed and Baerveldt glaucoma drainage device implantation in the pediatric population: A systematic review and meta-analysis

Glaucoma drainage devices (GDD) are increasingly utilized in the management of childhood glaucoma. This systematic review and meta-analysis assesses the efficacy of first-time Ahmed or Baerveldt implantation in children. PubMed, Embase, and Cochrane Library were searched for relevant English-language, peer-reviewed literature. Postoperative outcomes were pooled using random effects regression models with restricted maximum likelihood estimation. Thirty-two studies (1,221 eyes, 885 children) were included. Mean ± standard deviation preoperative IOP was 31.8 ± 3.4 mm Hg. Pooled mean IOP at 12 and 24 months postoperatively were 16.5 mm Hg (95% CI, 15.5-17.6) and 17.6 mm Hg (95% CI, 16.4-18.7), respectively. Pooled proportions of success were 0.87 (95% CI, 0.83-0.91) at 12 months, 0.77 (95% CI, 0.71-0.83) at 24 months, 0.54 (95% CI, 0.44-0.65) at 48 months, 0.60 (95% CI, 0.48-0.71) at 60 months, and 0.37 (95% CI, 0.32-0.42) at 120 months. There were no differences in proportion of success at 12 and 24 months among eyes that received Ahmed and Baerveldt tube shunts, nor between eyes with primary glaucoma, glaucoma following cataract surgery, or other secondary glaucoma. Our findings show that Ahmed and Baerveldt shunts substantially reduced IOP for at least 24 months in childhood glaucoma, with similar findings among device types and glaucoma etiologies.

Long-term surgical outcomes of two different Ahmed Valve implantation techniques in refractory glaucoma: Scleral flap vs scleral tunnel

PURPOSE

To compare the outcomes and complications of the partial-thickness scleral flap technique to the long scleral tunnel technique in patients who underwent mitomycin C (MMC)-augmented Ahmed glaucoma valve (AGV) implantation.

PATIENTS AND METHODS

In this retrospective study, we reviewed 139 eyes of 137 patients with refractory glaucoma who underwent AGV-Model FP7 implantation. The eyes were divided into the scleral flap group (n = 74) and the scleral tunnel group (n = 65).

RESULTS

The mean follow-up was 57.91 ± 18.18 months for the flap and 61.18 ± 15.13 months for the tunnel group (p = 0.2499). The postoperative intraocular pressure (IOP) at 1 to 6 years was significantly lower than the baseline IOP in each group (p < 0.001). The average number of postoperative glaucoma medications decreased in the tunnel group (p = 0.0001) and in the flap group (p = 0.6194) compared to baseline. No statistically significant differences in postoperative visual acuity (p = 0.6396) and cumulative success (p = 0.054) were noted between the two groups. Conjunctival erosion or tube migration only occurred in the flap group. Significantly more reoperations were performed in the flap than in the tunnel group (p = 0.048).

CONCLUSIONS

Both MMC-augmented AGV tube implantation methods lowered IOP. The flap technique was associated with higher rates of postoperative serious complications and more reoperations than the tunnel technique. Previous glaucoma surgery and the technique used to implant the surgical tube proved to be significant risk factors for conjunctival erosion.

TUBE VERSUS TRABECULECTOMY IN JUVENILE-ONSET OPEN ANGLE GLAUCOMA - TREATMENT OUTCOMES IN TERTIARY HOSPITALS IN MALAYSIA

AIM OF THE STUDY

To compare the intraocular pressure (IOP) lowering effect and postoperative complications between primary augmented trabeculectomy and glaucoma drainage device (GDD) implantation as primary surgical intervention in patients with juvenile-onset open angle glaucoma (JOAG).

PATIENTS AND METHODS

A retrospective review study involving 20 eyes that underwent primary augmented trabeculectomy with mitomycin (MMC) and 10 eyes GDD implantation in 3 tertiary centres in Malaysia between 1 January 2013 and 31 December 2019. They were followed up for at least 12 months postsurgical intervention. Intraocular pressure (IOP), number of topical IOP lowering medication and complications were evaluated at 1, 3, 6 and 12 months post-intervention. Based on the IOP, the success was divided into complete and partial success, and failure. IOP and postsurgical complications were compared using the Repetitive Measure Analysis of Variance (RM ANOVA) and the Pearson chi-square test.

RESULTS

Both methods were effective in lowering the IOP. Eyes with primary augmented trabeculectomy have significant lower IOP compared to GDD implantation (p = 0.037). There was a higher incidence of postoperative hypotony (30%) in the trabeculectomy group. There was also a significant reduction of mean number of topical pressure-lowering drugs required postoperatively (p = 0.015). Complete success was achieved in 100% of eyes with trabeculectomy and 67% in GDD implantation (p = 0.047).

CONCLUSIONS

Primary augmented trabeculectomy and GDD implantation are good surgical options for the treatment of JOAG. Both methods provide IOP lowering at 1 year. However, trabeculectomy provides better pressure lowering, compared to GDD implantation in patients with JOAG.

Short-term Postoperative Visual Acuity Decrease and Recovery after Ahmed Tube Shunt Procedure for Glaucoma

PURPOSE

To elucidate the vision loss and recovery course after the Ahmed tube shunt procedure 6 months postoperatively. To identify risk factors associated with significant vision loss.

DESIGN

Retrospective chart review.

PARTICIPANTS

One eye of all adult patients who underwent an Ahmed glaucoma valve procedure from January 2008 to December 2017 with a minimum 6-month follow-up.

METHODS

Patients' preoperative and postoperative corrected visual acuity (CVA) were documented for 1 week, 1 month, 3 months, and 6 months postoperatively.

MAIN OUTCOME MEASURES

Preoperative and postoperative CVA at various time points were compared using repeated-measures analysis of variance. The proportions of patients with mild (<3 lines of Snellen CVA loss), moderate (3-5 lines, inclusive), and severe (>5 lines) vision loss were calculated and compared using a chi-square test. Logistic regression analysis was conducted to identify risk factors associated with a loss of 3 or more lines of CVA 6 months after surgery.

RESULTS

A total of 375 patients were included, whose mean preoperative CVA was 0.76. At 1 week postoperatively, mean CVA worsened to 0.96 (P < 0.05), but recovered back to preoperative level by the third postoperative month (P > 0.05). In terms of any vision loss, 55.6% of patients had worse CVA than preoperation at 1 week postoperatively, including 23.5% who had 3 or more lines of vision loss; these proportions decreased to 39.2% (P < 0.001) and 9.3%, respectively, by 6 months postoperatively. The most common causes of significant vision loss were preexisting ocular conditions and cataract progression. Postoperative antimetabolite injection was associated with a lower risk of 3 or more lines of CVA loss 6 months postoperatively (odds ratio, 0.44; P = 0.023).

CONCLUSIONS

After the Ahmed tube shunt procedure, the worst CVA occurred at 1 week postoperatively and mean CVA returned to the preoperative level by month 3 postoperatively. Approximately 40% of patients had any CVA loss compared with preoperation, and 9.3% of patients had 3 or more lines of CVA loss at month 6 postoperatively. Postoperative antimetabolite injection was associated with a lower risk of 3 or more lines of postoperative vision loss.

Safety and Efficacy of Second Ahmed Valve Implant in Refractory Glaucoma

BACKGROUND

Refractory glaucoma still represents a challenge for ophthalmologists to manage intraocular pressure. The present study aimed to evaluate long term efficacy and safety of a second Ahmed valve implantation after the failure of a first implant in patients with refractory glaucoma and elevated intraocular pressure (IOP).

METHODS

Retrospective, multicenter non-comparative case series. Twenty-eight patients were retrospectively recruited between January 2011 and December 2017. Demographic data, glaucoma type, visual acuity, intraocular pressure, medical therapy, and complications were registered. Three criteria of success were established: Type 1 surgical success: IOP ≤ 15 mmHg and a reduction of IOP ≥ 40% from baseline; Type 2 surgical success: IOP ≤ 18 mmHg and a reduction of IOP ≥ 30% from baseline; and Type 3 surgical success: IOP ≤ 21 mmHg and a reduction of IOP ≥ 20% from baseline. Surgical failure has been established as IOP less than 5 mmHg or over 21 mmHg and less than a 20% reduction of IOP from baseline despite medications in two consecutive visits, light perception loss referable to glaucoma, and the necessity for further glaucoma surgery. Failure was observed in six (21%) patients. (3) Results: Mean IOP and mean glaucoma medication number significantly reduced from baseline after the second implantation, and the surgical success rate at 72 months ranged from 10% to 78% based on the different criteria of success. Failure was observed in six (21%) patients.

CONCLUSIONS

This study confirmed the safety and efficacy of a second Ahmed valve implantation in patients with refractory glaucoma and elevated IOP at baseline.

Surgical outcomes of a new affordable non-valved glaucoma drainage device and Ahmed glaucoma valve: comparison in the first year

BACKGROUND

A new low-cost, indigenously manufactured, non-valved glaucoma drainage device (GDD) has been introduced and its design is based on the Baerveldt Glaucoma Device. We aim to demonstrate the efficacy and safety of this GDD (Aurolab aqueous drainage implant, AADI) vis-à-vis the valved device, Ahmed glaucoma valve (AGV), in the management of refractory glaucomas.

DESIGN

Retrospective, comparative, interventional.

PARTICIPANTS

Case review of consecutive patients who underwent GDD surgery by a single fellowship-trained surgeon at a Tertiary Centre between January 2014 and November 2016.

PRIMARY OUTCOME MEASURE

Intraocular pressure (IOP).

SECONDARY

Antiglaucoma medication (AGM), LogMAR best-corrected visual acuity (BCVA), complications.

RESULTS

A total of 88 eyes of 83 patients were included; 36 eyes received AGV and 52 AADI. Preoperative parameters were similar between groups. Median follow-up was 13 and 12 months for AADI and AGV, respectively. Overall success rate was higher in AADI (92.3%) vs AGV (80.5%) (p<0.001). The median IOP in mm Hg (Quartiles; IQR) (AADI 14 (10,15;5) vs AGV 16 (14,20;6)) and AGM (AADI: 0 (0,1;1) vs AGV 2 (1,2.75;1.75)) was significantly lower in the AADI group at last follow-up (p<0.001). LogMAR BCVA improved in both groups; complication rates (AADI 44.2% vs AGV 52.7%) were comparable (p=0.59).

CONCLUSIONS

Both procedures were effective in reduction of IOP and need for AGM. Nevertheless, overall success rate was higher in the AADI group and IOP and number of AGM required was significantly lower in the AADI group; this affordable GDD could have a tremendous impact in the management of refractory glaucomas in low-income to middle-income countries.

Incidence of Conjunctival Exposure following Drainage Device Implantation in Patients with Glaucoma

Purpose

To evaluate prior studies including a glaucoma drainage device and to describe the timing and incidence of conjunctival exposure. A meta-analysis of previously published articles.

Methods

Articles included were prospective, single cohort, or comparative parallel design, with a mean treatment period of at least 3 months and at least 30 patients per treatment arm. We limited our analysis to studies that evaluated the most common devices, including Ahmed, Baerveldt, and Molteno.

Results

We included 38 studies containing 45 treatment arms (16 Ahmed, 12 Baerveldt, and 17 Molteno). These studies included 3,105 patients and 3,255 eyes with an average follow-up of 26.1±3.3 months. The overall incidence of exposure was 2.0±2.6% (n=64) of eyes with an average exposure/month of 0.09±0.14%. There was no significant correlation between study length and incidence of exposure (p=0.11), although multivariate regression analysis identified length of follow-up as a risk factor for exposure (p=0.001). Among individual drainage devices, there was no significant difference in the incidence of exposure (p=0.22) or percent exposure per month (p=0.18). In addition, no difference existed in the incidence of exposure between sizes for the Baerveldt 250, 350 or 500 mm (p=0.7), number of plates for the Molteno Single or Double (p=0.3), nor between the composition of the Ahmed Silicone or Polypropylene (p=0.7).

Conclusions

This study suggests that tube exposure of glaucoma implants is unusual and the incidence does not differ between the Ahmed, Baerveldt, and Molteno implants. However, exposure appears to occur at any time within the first 5 years following implantation.

Combined Phacoemulsification and Ahmed Valve Glaucoma Drainage Implant: A Retrospective Case Series

Purpose

To report on the efficacy and safety of combined phacoemulsification and an Ahmed valve glaucoma drainage implant with respect to visual acuity improvement, intraocular pressure (IOP) control, and requirement for antiglaucoma medication.

Methods

A retrospective chart review was conducted of 41 eyes (31 patients) with coexisting visually significant cataracts and uncontrolled glaucoma who had combined phacoemulsification and Ahmed valve implantation. The outcome measures were: visual acuity, IOP, antiglaucoma medication requirements, and intra- and post-operative complications. Success was categorized as absolute (IOPp<21 mmHg without the need for antiglaucoma medication) and relative (IOPp<21 mmHg with one or more antiglaucoma medications). Failure was considered to be an IOPp<6 mmHg or IOP>21 mmHg on maximally tolerated medications or any devastating complication.

Results

The mean patient age was 67.3±5.9 years old. The mean visual acuity improved from 0.73±0.5 to 0.16±0.16 (p=0.000). The mean IOP decreased from 28.2±3.1 to 16.8±2.1 (p=0.000, 40.4%), while the number of antiglaucoma medication decreased from 2.6±0.66 to 1.2±1.4 (p=0.000). The absolute and relative success rates were 56.1% and 31.7%, respectively; 5 eyes (12.2%) were considered failures. There were no intraoperative complications; postoperative complications occurred in 8 eyes (19.5%). A hypertensive phase was detected in 12 (29.3%) eyes.

Conclusions

Combined phacoemulsification and Ahmed valve glaucoma drainage implantation is a safe and effective alternative to phacotrabeculectomy in patients with coexisting cataract and refractory glaucoma.

Angle-Closure Glaucoma after Piggyback Intraocular Lens Implantation

Purpose

To report a case of angle closure glaucoma after piggyback intraocular lens implantation and its treatment.

Methods

The authors present the case of a 75-year-old woman who was seen in the emergency department with angle closure glaucoma. Two years before she had undergone piggyback intraocular lens (IOL) implantation in order to correct a refractive error after cataract surgery. Ultrasound biomicroscopy revealed a closed angle with synechiae in 360° as well as the presence of two IOLs: one in the capsular bag and the other in the ciliary sulcus. Extraction of the anterior IOL was precluded due to the poor endothelial count. Peripheral iridotomy and trabeculectomy were ineffective to lower the intraocular pressure (IOP); the authors decided to implant with an Ahmed valve and to place the valve's tube between the two IOLs to protect the endothelium.

Results

After Ahmed valve implantation, IOP maintains stable around 10–12 mmHg without medical treatment.

Conclusions

Ahmed valve implantation is a good option in angle closure glaucoma due to piggyback. The placement of the valve's tube between the two IOLs is a good option to protect corneal endothelium.

[Ahmed valve in glaucoma surgery]

This is a review on Ahmed valve application in glaucoma surgery. It contains, in particular, data on the Ahmed valve efficiency, results of experimental and histological studies of filtering bleb encapsulation, examines the use of antimetabolites and anti-VEGF agents, and discusses implantation techniques. The current appraisal of antimetabolites delivery systems integrated into the Ahmed valve is presented. Various complications encountered in practice and preventive measures are also covered.

Long-term clinical outcomes of Ahmed valve implantation in patients with refractory glaucoma

PURPOSE

To evaluate the long-term efficacy of intraocular pressure (IOP) reduction and complications of Ahmed Glaucoma Valve (AGV) implantation in patients with refractory glaucoma.

DESIGN

Retrospective study.

SUBJECTS

The study involved 302 refractory glaucoma patients who underwent AGV implantation and had a minimum follow-up of 6 months between March 1995 and December 2013.

METHODS

An operation was defined as successful when (1) the postoperative IOP remained between 5 and 21 mmHg and was reduced 30% compared to the baseline IOP with or without medication, (2) there was no loss of light perception or vision-threatening severe complications, and (3) no additional filtering or aqueous drainage surgery was required. Clinical records were reviewed.

MAIN OUTCOME MEASURES

IOP, anti-glaucoma medications, and complications.

RESULTS

The mean follow-up period was 62.25 months (range, 6 to 190 months). The cumulative probability of success was 89% at 6 months, 81% at 1 year, 66% at 3 years, 44% at 10 years, and 26% at 15 years. IOP was reduced from a mean of 32.2 ± 10.5 mmHg to 18.6 ± 9.1 mmHg at 1 month, 15.2 ± 7.0 mmHg at 6 months, and 14.2 ± 3.5 mmHg at 15 years. Surgical failures were significantly increased when preoperative IOP was high, and when severe complications occurred after AGV implantation (P < 0.05).

CONCLUSION

AGV implantation was successful for IOP control in patients with refractive glaucoma in the long term. However, the success rate of surgery decreased over time. Preoperative high IOP and severe complications related to the operation were significant risk factors for failure.

A Review of the Ahmed Glaucoma Valve Implant and Comparison with Other Surgical Operations

The Ahmed glaucoma valve (AGV) is a popular glaucoma drainage implant used for the control of intraocular pressure in patients with glaucoma. While in the past AGV implantation was reserved for glaucoma patients poorly controlled after one or more filtration procedures, mounting evidence has recently encouraged its use as a primary surgery in selected cases. AGV has been demonstrated to be safe and effective in reducing intraocular pressure in patients with primary or secondary refractory glaucoma. Compared to other glaucoma surgeries, AGV implantation has shown favorable efficacy and safety. The aim of this article is to review the results of studies directly comparing AGV with other surgical procedures in patients with glaucoma.

Combined Scleral Flap with Donor Scleral Patch Graft for Anterior Tube Placement in Glaucoma Drainage Device Surgery

Purpose. To report a new technique for anterior placement of tubes for glaucoma drainage devices to reduce the risk of tube erosions. Methods. Retrospective review of select cases of Ahmed Valve surgery combined with the novel method of a limbal-based scleral flap covered by a scleral patch graft to cover the tube at the entrance through the limbus. Intraoperative and postoperative illustrations are shown to highlight the method of tube placement. Results. In this retrospective case series, 3 patients are presented illustrating the technique. Two had neovascular glaucoma and one had primary open-angle glaucoma (POAG). On average, intraocular pressure was reduced from 39 ± 14 mmHg to 15 ± 2 mmHg and the number of glaucoma medications was reduced from 4 ± 1 to 0. Preoperative and most recent visual acuities were hand-motion (HM) and HM, 20/60 and 20/50, and 20/70 and 20/30, respectively. Conclusion. The combination of a limbal-based scleral flap with scleral patch graft to cover the tube with glaucoma drainage devices may be an effective means to reduce erosion and protect against endophthalmitis.

The Ahmed Glaucoma Valve in Refractory Glaucoma: Experiences in Southwest Ethiopia

Background

The management of refractory glaucoma is a challenging task for any glaucoma surgeon. This study is aimed to evaluate the efficacy of Ahmed Glaucoma Valve implantation in refractory glaucomas in South-West Ethiopia.

Methods

A retrospective review was conducted on the charts of consecutive patients treated with Ahmed glaucoma valve implantation at Jimma University Specialized Hospital between August 2012 and August 2014. Success was defined as Intraocular Pressure (IOP) less than 22 mm Hg and greater than 5mm Hg at 6 months, with at least 30% reduction from baseline, without medical therapy (complete success) or either with or without medication (qualified successes).

Results

A total of 12 eyes of 11 patients were included. The mean age of patients was 40.7 (SD= 19.0) years; 63.6% of them were males. The main types of glaucoma were pseudoexfoliative (3 eyes), uveitic (2 eyes), chronic angle closure (2 eyes) and Juvenile Open Angle (JOAG) (2 eyes). The mean IOP was reduced from preoperative level (32.75±7.14 mmHg) to (15.75 ±4.35 mmHg) at six postoperative months, (P<0.001); 66.7% eyes had complete successes while 83.3% had qualified success. Intra-operative complications were encountered in 2(16.7%) eyes, while 5/12 (41.7%) eyes had post-operative complications-hypotony (one with choroidal effusion) and progression of cataract in 2 eyes each. Hypertensive phase was diagnosed in 2(16.7%) eyes.

Conclusion

The Ahmed glaucoma valve implant appears to be effective and relatively safe for treating complicated glaucomas with success rate comparable with those reported from other studies. KEYWORDS: Ahmed glaucoma valve, refractory glaucoma, complications, Ethiopia

The Results of the Use of Ahmed Valve in Refractory Glaucoma Surgery

The treatment of refractory glaucoma (RG) is challenging. The commonly adopted strategy in RG treatment is a glaucoma drainage device (GDD) implantation, which despite its radical nature may not always provide the desired intraocular pressure (IOP) levels for a long term. This review is based on the scientific literature on Ahmed glaucoma valve (AGV) implantation for refractory glaucoma. The technique of AGV implantation is described and data for both the types, FP7 and FP8 performance are presented. The outcome with adjunct antimetabolite and anti-VEGF drugs are also highlighted. An insight is given about experimental and histological examinations of the filtering bleb encapsulation. The article also describes various complications and measures to prevent them.

How to cite this article: Bikbov MM, Khusnitdinov II. The Results of the Use of Ahmed Valve in Refractory Glaucoma Surgery. J Curr Glaucoma Pract 2015;9(3):86-91.

Long-term Outcomes of Ahmed Glaucoma Valve Implantation in Refractory Glaucoma at Farabi Eye Hospital, Tehran, Iran

PURPOSE

To describe long-term outcomes and complications of Ahmed glaucoma valve (AGV) implantation in subjects with refractory glaucoma at Farabi Eye Hospital, Tehran, Iran.

MATERIALS AND METHODS

This retrospective cohort study evaluated patient records of all subjects with refractory glaucoma who had undergone AGV implantation up to January 2013. The main outcome measure was the surgical success rate. Complete success was defined as intraocular pressure (IOP) <22 mmHg, without anti-glaucoma medications or additional surgery. Qualified success was IOP <22 mmHg regardless of number of anti-glaucoma medications. In all cases, loss of vision (no light perception) was considered an independent indicator of failure. Data were also collected on intraoperative and postoperative complications.

RESULTS

Twenty-eight eyes were included in the study. With a mean follow-up of 48.2 ± 31.7 months (median: 40.50 months; range: 3-124 months), the IOP decreased from a mean preoperative value of 30.8 ± 5.6 mmHg to 20.0 ± 6.4 mmHg at last visit. The number of medications decreased from 3.7 ± 0.4 preoperatively to 2.5 ± 1.1 postoperatively. Cumulative qualified success was achieved in 69% of eyes. Mean time to failure according to qualified success criteria was 92.3 ± 9.4 months. Postoperative complications were recorded in 16 (57.1%) eyes. The most common complication was focal endothelial corneal decompensation at the site of tube-cornea touch.

CONCLUSION

AGV implantation with adjunctive topical anti-glaucoma drops controlled IOP in approximately 70% of eyes with refractory glaucoma with a median of 40.5 months of follow-up. However, complication rates were higher.

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 than 21 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 56wk postoperatively. Logarithm values of IOP were calculated and compared.

RESULTS

The study group was comprised of 30 patients (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 and 56wk respectively. BCVA was ≥ 6/60 in 11 eyes preoperatively, and five eyes had BCVA≥6/60 at 56wk postoperatively. Preoperatively, more than four medications were used to treat glaucoma in 21 eyes. At 12wk postoperatively, no medications were required to control IOP in 20 eyes. At 56wk 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.

Short term outcome of Ahmed glaucoma valve implantation in management of refractory glaucoma in a tertiary hospital in Oman

Background:

We present outcomes of Ahmed Glaucoma Valve (AGV) implantation in treating refractory glaucoma in a tertiary hospital in Oman. Refractory glaucoma was defined as previously failed conventional glaucoma surgery and an uncontrolled intraocular pressure (IOP) of more than 21 mm Hg despite treatment with three topical and/or oral therapy.

Materials and Methods:

This historical cohort study was conducted in 2010. Details of medical and surgical treatment were recorded. Ophthalmologists examined eyes and performed glaucoma surgeries using AGV. The best corrected distant vision, IOP, and glaucoma medications were prospectively reviewed on 1^st day, 1^st, 6^th, 12^th week postoperatively, and at the last follow up.

Result:

Glaucoma specialists examined and treated 40 eyes with refractory glaucoma of 39 patients (20 males + 19 females). Neo-vascular glaucoma was present in 23 eyes. Vision before surgery was <3/60 in 21 eyes. At 12 weeks, one eye had vision better than 6/12, seven eyes had vision 6/18 to 6/60, and eight eyes had vision 6/60 to 3/60. Mean IOP was reduced from 42.9 (SD 16) to 14.2 (SD 8) and 19.1 (SD 7.8) mmHg at one and 12 weeks after surgery, respectively. At 12 weeks, five (12.5%) eyes had IOP controlled without medication. In 33 (77.5%) eyes, pressure was controlled by using one or two eye drops. The mean number of preoperative anti-glaucoma medications (2.38; SD 1.1) was reduced compared to the mean number of postoperative medications (1.92; SD 0.9) at 12 weeks.

Conclusion:

We succeeded in reducing visual disabilities and the number of anti-glaucoma medications used to treat refractory glaucoma by AGV surgery.

Early Ahmed glaucoma valve implantation after penetrating keratoplasty leads to better outcomes in an Asian population with preexisting glaucoma

BACKGROUND

To evaluate the efficacy of Ahmed Glaucoma Valve (AGV) surgery and the optimal interval between penetrating keratoplasty (PKP) and AGV implantation in a population of Asian patients with preexisting glaucoma who underwent PKP.

METHODOLOGY/PRINCIPAL FINDINGS

In total, 45 eyes of 45 patients were included in this retrospective chart review. The final intraocular pressures (IOPs), graft survival rate, and changes in visual acuity were assessed to evaluate the outcomes of AGV implantations in eyes in which AGV implantation occurred within 1 month of post-PKP IOP elevation (Group 1) and in eyes in which AGV implantation took place more than 1 month after the post-PKP IOP evaluation (Group 2). Factors that were associated with graft failure were analyzed, and the overall patterns of complications were reviewed. By their final follow-up visits, 58% of the patients had been successfully treated for glaucoma. After the operation, there were no statistically significant differences between the groups with respect to graft survival (p = 0.98), but significant differences for IOP control (p = 0.049) and the maintenance of visual acuity (VA) (p<0.05) were observed. One year after surgery, the success rates of IOP control in Group 1 and Group 2 were 80% and 46.7%, respectively, and these rates fell to 70% and 37.3%, respectively, by 2 years. Factors that were associated with a high risk of AGV failure were a diagnosis of preexisting angle-closure glaucoma, a history of previous PKP, and a preoperative IOP that was >21 mm Hg. The most common surgical complication, aside from graft failure, was hyphema.

CONCLUSIONS/SIGNIFICANCE

Early AGV implantation results in a higher probability of AGV survival and a better VA outcome without increasing the risk of corneal graft failure as a result of post-PKP glaucoma drainage tube implantation.

Surgical outcomes of different Ahmed Glaucoma Valve implantation methods between scleral graft and scleral flap

Purpose

To compare the surgical outcomes of the two different methods used for Ahmed Glaucoma Valve (AGV) implantation between the donor scleral graft method and the partial-thickness scleral flap method.

Methods

We retrospectively reviewed medical records of 28 eyes of 26 patients diagnosed as neovascular glaucoma followed by AGV implantation. Based on the surgical method, the included eyes were divided into two groups. In the graft group (n = 18), the drainage tube was inserted into the anterior chamber, and then covered with preserved donor sclera. In the flap group (n = 10), the drainage tube was inserted under the partial-thickness scleral flap, and then covered with the flap. We compared the postoperative intraocular pressure (IOP), surgical success rates, and postoperative complications between the two groups.

Results

Postoperative IOP was not significantly different between the two groups (p = 0.967, 0.495 at 12 months, 24 months, respectively, by the Mann-Whitney U-test). The mean success periods were 53.1 ± 10.1 months in the graft group versus 50.9 ± 9.4 months in the flap group (p = 0.882 by log rank test), and cumulative success rates were 77.8% and 80.0% at one year, respectively. However, tube migration occurred more frequently in the flap group than in the graft group (p = 0.037 by Fisher's exact test).

Conclusions

In AGV surgery for neovascular glaucoma, the scleral graft method may be associated with relatively less complication about tube migration than the scleral flap method. The surgical results, however, were not statistically different.

Ahmed glaucoma valve in post-penetrating-keratoplasty glaucoma: a critically evaluated prospective clinical study

Aim:

The aim was to evaluate the outcome of Ahmed glaucoma valve (AGV) in post-penetrating-keratoplasty glaucoma (PKPG).

Materials and Methods:

In this prospective study, 20 eyes of 20 adult patients with post-PKPG with intraocular pressure (IOP) >21 mmHg, on two or more antiglaucoma medications, underwent AG (model FP7) implantation and were followed up for a minimum of 6 months. Absolute success was defined as 5 <IOP <21 mmHg and qualified success as 5 <IOP <21 mmHg with medications or minor procedures.

Results:

The mean IOP decreased from 42.95 ± 10.24 to 17.69 ± 3.64 mmHg (P <0.001) and the use of medications dropped from 2.92 to 0.39 (P <0.001) after AGV implantation. The absolute success was achieved in 11 eyes and qualified success in 9. There was no significant change in best corrected visual acuity, graft clarity, or graft thickness. Six device-related complications occurred after AGV implantations which were successfully managed with medical or minor surgical therapy.

Conclusions:

Postkeratoplasty refractory glaucoma managed by AGV implantation revealed a satisfactory outcome up to 6 months of follow-up.

Surgical management of glaucoma: an Indian perspective

Glaucoma is a serious sight-threatening disorder aptly named the Silent thief of sight. India, being the second most populous country in the world, has about 20% of the world glaucoma population. The complex geographical and socioeconomic architecture and the economic extremes have a profound effect on its health system. The present times are abundant with fresh developments in the field of glaucoma. Though newer modalities are present in India, they are not ample and are unequally distributed. Adherence and persistence with medical therapy is an issue owing to a multitude of factors. In such a setting, most of the ophthalmologists find themselves performing glaucoma surgeries quite often. In the present era, there are a number of new surgeries to choose from, especially procedures which are nonpenetrating and blebless. Faced with a spectrum of surgeries from shunts to canal surgeries and trabecular bypass devices, the surgeon is often in a dilemma. Still, trabeculectomy remains the gold standard with an increasing trend toward glaucoma drainage devices. The new procedures and devices are worth exploring but await long-term results, good training of surgeons and cost effectiveness.

Ahmed glaucoma valve and single-plate Molteno implants in treatment of refractory glaucoma: a comparative study

PURPOSE

To report 2-year follow-up data after Ahmed valve implantation (New World Medical, Inc) and Molteno single-plate implantation surgical treatment of refractory glaucoma.

DESIGN

Prospective, randomized, comparative study.

METHODS

Patients with refractory glaucoma, defined as uncontrolled intraocular pressure (IOP) of more than 21 mm Hg despite maximal antiglaucoma medication, previously failed nonseton surgical treatment, or a combination thereof were included. Ninety-two patients were allocated randomly to each of the study groups and underwent implantation of either the Ahmed valve implant (model FP7; 184 mm(2) surface area) or Molteno single-plate implant (134 mm(2) surface area) and were followed up for 24 months. Main outcome measures were IOP and surgical success rate. Other outcome measures were changes in visual acuity, number of ant-glaucoma medications, mean deviation of visual field, and rate of intraoperative and postoperative complications.

RESULTS

Those who successfully completed the trial (28 in the Molteno group and 29 in the Ahmed group) achieved significantly less IOP and fewer glaucoma medications, but worse visual acuity 24 months after surgery. The Molteno group, compared with the Ahmed group, achieved significantly lower IOPs after the early postoperative period until the end of the study. Both groups reasonably maintained visual field during the follow-up. The rate of surgical failure was comparable in both groups. Median survival time was 24 months for both groups. There were no devastating intraoperative or postoperative complications in either group.

CONCLUSIONS

Both Ahmed and Molteno implants successfully preserved visual field, although IOP control was more pronounced in the Molteno implant group.

Graft-free Ahmed tube insertion: a modified method at 5 mm from limbus

Objective

To determine the medium-term outcome of Ahmed implants inserted through a needle tract at 5 mm from limbus that eliminates the need for a donor scleral graft.

Methods

A retrospective case series of 19 patients undergoing Ahmed implant surgery for refractory glaucoma with a mean follow-up of 12 months. Primary outcome measures included control of intraocular pressure after surgery. Secondary outcome measure included the frequency of intraoperative and postoperative complications.

Results

Intraocular pressure was maintained between 6 and 21 mmHg throughout the study. There was no postoperative hypotony. There were no complications related to this modified technique.

Conclusion

Needle tract at 5 mm from limbus maintains implant’s ability to control intraocular pressure and eliminates the need for a donor scleral graft or heterologous material.

Ahmed valve implantation with adjunctive mitomycin C and 5-fluorouracil: long-term outcomes

PURPOSE

To evaluate long-term outcomes after Ahmed valve implantation in patients with glaucoma when using adjunctive intraoperative mitomycin C (MMC) and postoperative 5-fluorouracil (5-FU).

DESIGN

Retrospective, interventional, consecutive case series.

METHODS

A consecutive series of eyes undergoing Ahmed valve implantation, either alone (AHMED eyes) or in combination with cataract surgery (AHMED+PHACO), using both intraoperative MMC and postoperative 5-FU were evaluated. Failure was defined as the first occurrence of any of the following: 1) the first of three consecutive visits where intraocular pressure (IOP) was >18 mm Hg or <20% IOP reduction from baseline and the final number of topical medications was not reduced by at least two from baseline, 2) the need for additional surgery, or 3) the development of serious complications.

RESULTS

A total of 130 eyes underwent Ahmed valve implantation with intraoperative exposure to 0.5 mg/ml MMC (median time: eight minutes; range, four to 10) and postoperative subconjunctival injections of 5 mg of 5-FU (median: five injections; range, zero to nine). Kaplan-Meier estimates of the cumulative probability of valve success and confidence interval (CI) at the sixth follow-up year were 0.72 (95% CI, 0.59 to 0.82) for AHMED eyes (n = 88), 0.84 (95% CI, 0.65 to 0.93) for AHMED+PHACO eyes (n = 42). A median of two fewer medications were required relative to baseline for both AHMED and AHMED+PHACO eyes.

CONCLUSIONS

The adjunctive use of both intraoperative MMC and postoperative 5-FU with Ahmed valve implantation results in high success rates. IOP was well controlled in the majority of patients within the six-year postoperative period.

Long-term outcomes of Ahmed glaucoma valve implantation in refractory glaucomas

PURPOSE

To evaluate the long-term efficacy of intraocular pressure (IOP) reduction and complications of Ahmed glaucoma valve (AGV) implantation (New World Medical, Inc, Rancho Cucamonga, California, USA) in refractory glaucoma.

DESIGN

Retrospective cohort study.

METHODS

Retrospective medical records from 64 patients (78 eyes) with refractory glaucoma who underwent AGV implantation with a minimum of three years of follow-up were reviewed. Data regarding age, gender, race, eye laterality, specific glaucoma diagnosis, best-corrected visual acuity (BCVA), number of medications, IOP, visual fields, surgical complications, and follow-up interval were collected from all visits and were analyzed. The primary outcome measure was cumulative probability of success defined as IOP of less than 21 mm Hg and of 5 mm Hg or more with a minimum of 15% reduction from baseline IOP, without additional glaucoma surgery or loss of light perception. Secondary outcomes included IOP and number of medications at three, six, 12, 24, 36, 48, and 60 months after surgery, surgical complications, and final BCVA.

RESULTS

The cumulative probability of success was 80% and 49% at one and five years, respectively. IOP was reduced from a mean of 30.4 +/- 10.7 mm Hg to 17.0 +/- 5.0 mm Hg at 12 months and 15.9 +/- 3.0 mm Hg at 60 months (P < .001). The number of medications decreased from 3.2 +/- 1.0 medications at baseline to 1.6 +/- 0.4 at 12 months and 2.1 +/- 0.2 at 60 months (P < .001). Prior glaucoma surgery and the silicone type of AGV were statistically significant risk factors for failure (P < .001).

CONCLUSIONS

Approximately 50% of single-plate AGV implantations in refractory glaucoma were considered successful after five years of follow-up. Prior glaucoma surgery was a statistically significant risk factor for failure.