Intermediate-term clinical experience with the Ahmed Glaucoma Valve implant

doi:10.1016/S0002-9394(98)00394-8

American Journal of Ophthalmology

Volume 127, Issue 1, January 1999, Pages 27-33

This study was presented in part at the annual meeting of the Association for Research in Vision and Ophthalmology in Fort Lauderdale, Florida, May 12, 1998.

https://doi.org/10.1016/S0002-9394(98)00394-8 Get rights and content

Abstract

PURPOSE: We studied the intermediate-term clinical experience with the Ahmed Glaucoma Valve implant (New World Medical, Inc, Rancho Cucamonga, California).

METHODS: In this multicenter, retrospective case series, we studied 159 eyes (144 patients) treated with the Ahmed Glaucoma Valve with a mean ± SEM (standard error of mean) follow-up of 13.4 ± 0.7 months (range, 4 to 44 months). The mean ± SEM age was 60.9 ± 1.9 years (range, 0.1 to 103 years). Surgical success was defined as intraocular pressure less than 22 mm Hg and greater than 5 mm Hg without additional glaucoma surgery and without loss of light perception. Postoperative use of antiglaucoma medications was not a criterion for success or failure. The definition of hypotony was intraocular pressure of 5 mm Hg or less in two consecutive visits.

RESULTS: Intraocular pressure was reduced from a mean of 32.7 ± 0.8 mm Hg before surgery to 15.9 ± 0.6 mm Hg (P < .0001) at the most recent follow-up after surgery. The number of antiglaucoma medications was decreased from 2.7 ± 0.1 before surgery to 1.1 ± 0.1 after surgery (P < .0001). The cumulative probability of success was 87% at 1 year and 75% at 2 years after surgery (Kaplan-Meier life-table analysis). Postopera-tively, 24 (15%) of 159 eyes had intraocular pressure greater than or equal to 22 mm Hg. The visual acuity was improved or within one Snellen line in 131 eyes (82%). Complications occurred in 75 eyes (47%), the majority of which did not affect surgical outcome. The most common complication was obstruction of the tube, which was observed in 17 eyes (11%). Transient postoperative hypotony was found in 13 eyes (8%).

CONCLUSIONS: The Ahmed Glaucoma Valve implant is effective in lowering intraocular pressure, and postoperative hypotony is not commonly associated with this implant.²

Section snippets

Patients and methods

We reviewed the records of patients who were treated with the Ahmed Glaucoma Valve implant for increased intraocular pressure or glaucoma that was not responsive to medical treatment, laser treatment, or previous glaucoma surgery. A total of 144 patients (159 eyes) were included from four medical centers in the United States. Patients with less than 4 months of follow-up were excluded from the analysis.

After informed written consent was obtained, the Ahmed Glaucoma Valve was implanted by one of

Results

The characteristics of the patients in the study are summarized in Table 1. A total of 159 eyes in 144 consecutive patients were included during the study period, from July 1992 to June 1996. The mean ± SEM follow-up period was 13.4 ± 0.7 months (range, 4 to 44 months). The mean ± SEM age was 60.9 ± 1.9 years (range, 0.1 to 103 years). The majority of eyes were pseudophakic (96 eyes, 61%) at the time of surgery. The most common diagnoses were open-angle glaucoma (55 eyes, 35%), glaucoma

Discussion

A variety of aqueous drainage implants have been developed to treat recalcitrant glaucomas, including open-tube and valved designs.1, 2 The Ahmed Glaucoma Valve implant has a 185-mm² polypropylene body, which is larger than the single-plate Molteno implant and smaller than the Baerveldt implant. Its tapered chamber valve is designed to provide resistance to aqueous flow. We found transient postoperative hypotony in only 13 (8%) of 159 eyes treated with the this implant, and none required

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The History of Tube Shunts
2024, Advances in Ophthalmology and Optometry
Effect of Lens Status on the Outcomes of Glaucoma Drainage Device Implantation
2024, Ophthalmology Glaucoma
To assess the effect of lens status and cataract surgery on glaucoma drainage device (GDD) efficacy.
Retrospective cohort study.
Two hundred and forty-three eyes of 216 patients that underwent GDD implantation with $\geq$ 1 follow-up visit within 3 years postoperatively. Exclusion criteria included GDD combined with other ophthalmic procedures. 90%–94% of GDDs were Ahmed implants; 83%–90% had adjunctive mitomycin-C.
Outcomes were compared between phakic eyes (group A), eyes phakic at time of implantation but subsequently underwent cataract surgery within 3 years (group B), and pseudophakic eyes (group C). Outcomes were measured at 1, 3, 6, 12, 24, and 36 months after tube shunt implantation. Multivariable regression models were performed, adjusting for baseline characteristics.
Intraocular pressure (IOP) after GDD implantation. Secondary outcomes included change in visual acuity (VA), number of glaucoma eye drops, and rate of failure, defined as additional glaucoma surgery, vision decrease to no light perception, or IOP persistently ≤ 5 mmHg or > 21 mmHg or not reduced from baseline by 20%.
There were 65 eyes in group A, 52 in group B, and 126 in group C. Within group B, cataract surgery was performed at a mean of 1.3 ± 0.7 years after GDD implantation. There were no statistically significant differences in mean IOP or medications between the 3 groups at all time points up to 3 years postoperatively. Significant improvement in VA was noted in groups A and B compared to group C at 6 months, 1 year, and 2 years after implantation; however, by postoperative year 3, change in VA was similar across groups. There were no significant differences in the failure rate amongst groups (P = 0.68). IOP and medications up to 12 months after cataract surgery were similar compared to preoperative baseline. Group B had significantly more short-term (P = 0.02) and long-term (P < 0.001) postoperative complications than groups A or C, driven primarily by hypotony.
There were no differences in IOP, glaucoma medications, or rate of failure 3 years after GDD implantation based on lens status or after undergoing subsequent cataract surgery. These results may inform the management of patients with co-existing glaucoma and cataract.
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Pretreatment with frequent topical betamethasone in Ahmed glaucoma valve implantation
2022, Canadian Journal of Ophthalmology
To evaluate the efficacy of pretreatment with topical betamethasone in Ahmed glaucoma valve (AGV) implantation.
Randomized clinical trial.
Sixty-two eyes from 62 patients undergoing AGV.
We randomly assigned patients undergoing AGV to 2 arms of the study. The case group received AGV implantation with preoperative betamethasone eye drops, and the control group did not receive preoperative betamethasone. Follow-up examinations were performed on postoperative day 1, at least weekly for 4 weeks, and then every 1 to 3 months. Our main outcome measure was the rate of success, defined as intraocular pressure (IOP) <15 mm Hg and IOP ≤18 mm Hg.
We analyzed 62 eyes divided to case (n = 33) and control (n = 29) groups. The success rate was significantly higher in the intervention group than in the control group at 12 months postoperatively when considering either IOP < 15 or IOP < 18 mm Hg as success (p < 0.001) and also at 6 months when considering IOP < 18 mm Hg as success (p < 0.041). The reduction in the number of antiglaucoma medications used postoperatively was significantly higher in the betamethasone group at follow-up at 1 and 3 months and 1 year.
Pretreatment with topical betamethasone in AGV implantations increases the success rate and reduces the need for medications.
Évaluer l'efficacité de l'administration de bétaméthasone topique avant l'implantation d'une valve de glaucome Ahmed (AGV).
Étude clinique randomisée.
62 yeux de 62 patients devant recevoir une AGV.
Les patients qui devaient recevoir une AGV ont été répartis au hasard en 2 groupes : les sujets du groupe traité ont reçu la bétaméthasone (sous forme de collyre) avant l'implantation, tandis que le groupe témoin n'a pas reçu de bétaméthasone en phase préopératoire. Les examens de suivi ont été réalisés comme suit : jour postopératoire 1, au moins 1 fois par semaine pendant 4 semaines, et tous les 1 à 3 mois par la suite. Le paramètre principal reposait sur le taux de réussite, qui se définissait par l'obtention d'une pression intraoculaire (PIO) < 15 mm Hg et une PIO ≤ 18 mm Hg.
Ainsi, 62 yeux (33 dans le groupe traité et 29 dans le groupe témoin) ont été analysés. Le taux de réussite était significativement plus élevé dans le groupe traité, comparativement au groupe témoin, 12 mois après l'intervention en retenant le seuil de PIO < 15 ou de PIO ≤ 18 mm Hg à titre de mesure de la réussite (p < 0,001) de même que 6 mois après l'intervention en retenant le seuil de PIO ≤ 18 mm Hg à titre de mesure de la réussite (p < 0,041). La baisse du nombre de médicaments antiglaucomateux après l'intervention était significativement plus importante dans le groupe bétaméthasone lors du suivi à 1 mois, à 3 mois et à 1 an.
L'administration préalable de bétaméthasone topique avant l'implantation d'une AGV accroît le taux de réussite de l'intervention et diminue le nombre d'antiglaucomateux que doit prendre le patient après la chirurgie.
Tube Versus Trabeculectomy IRIS registry 1-Year Composite Outcome Analysis with Comparisons to the Randomized Controlled Trial
2021, American Journal of Ophthalmology
This study compared 1-year results for the composite treatment outcome from the Tube Versus Trabeculectomy (TVT) randomized controlled trial (RCT) to those from an IRIS^Ⓡ (Intelligent Research In Sight) Registry cohort of analogous eyes.
Retrospective clinical study with comparison to an RCT.
Subjects’ eyes in the IRIS Registry received either a glaucoma drainage implant (tube) or underwent trabeculectomy after a previous trabeculectomy and/or cataract extraction and had data for 1-year follow-up analyses.
Eyes were classified as failing if they had hypotony (intraocular pressure (IOP) ≤5 mm Hg) or inadequate IOP control (IOP >21 mm Hg or not reduced at least 20% below baseline) on 2 consecutive follow-up visits after 3 months, a reoperation for glaucoma, or no light perception vision and as successful otherwise. Failure risk was compared by treatment, demographic, and clinical variables and was compared to analogous failure risks from the TVT RCT.
The TVT IRIS Registry cohort included 419 eyes, 236 tube eyes (56.3%) and 183 trabeculectomy eyes (43.7%). In this cohort, there was no significant failure risk difference (12.3% for tube eyes and 16.4% for trabeculectomy eyes, P = 0.231). Comparing the studies, there was a significantly greater risk of failure in the TVT IRIS Registry tube eyes than in the TVT RCT tube eyes (3.8%; P <.001). Reasons for treatment failure included reoperations for glaucoma (none in the TVT RCT at 1 year).
Our results were different from those in the TVT RCT. Possible reasons include non-Baerveldt tubes, greater severity among tube eyes, and practice patterns that reflect real-world data, which are different than those in RCTs.
Strabismus After Ahmed Glaucoma Valve Implantation
2021, American Journal of Ophthalmology
Most reports of strabismus after glaucoma drainage device implantation study larger devices and rarely note the incidence of strabismus after Ahmed glaucoma valve (AGV) implantation. It is unknown if the pattern of strabismus is similar with smaller devices. We investigated characteristics of strabismus after AGV implantation.
Retrospective review.
Institutional study of 732 patients at our institution undergoing AGV implantation between 2013 and 2018. Rate and characteristics of strabismus were the primary outcome; age, gender, and location of AGVs were also analyzed.
We identified 29 patients who developed new-onset strabismus postoperatively after initial AGV implantation, for 4% incidence of strabismus. Twenty-one (72%) of these had diplopia. AGVs were implanted superotemporally in 21, superonasally in 5, inferotemporally in 1, and inferonasally in 2. Three patients were esotropic, 11 were exotropic, 4 had hypertropia, 2 had hypotropia, and 9 patients had combined horizontal/vertical strabismus (esotropia/hypotropia [n = 1] or exotropia/hypertropias [n = 8]). Exotropia was the most common type of strabismus in both the superotemporal and superonasal (60%) AGV groups. Superotemporal AGVs were more commonly associated with ipsilateral hypertropia (43%) than superonasal AGVs. Treatments included strabismus surgery (n = 14), prisms (n = 6), or an occlusive lens (n = 1).
In the largest single-center series of patients undergoing initial AGV implantation, the overall incidence of postoperative strabismus was 4%. This is comparable to strabismus incidence following implantation of other types of glaucoma drainage devices, even larger devices. The possibility of this complication should be discussed with patients prior to surgery.
Short-term Postoperative Visual Acuity Decrease and Recovery after Ahmed Tube Shunt Procedure for Glaucoma
2020, Ophthalmology Glaucoma
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.
Retrospective chart review.
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.
Patients’ preoperative and postoperative corrected visual acuity (CVA) were documented for 1 week, 1 month, 3 months, and 6 months postoperatively.
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.
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).
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.

View all citing articles on Scopus

^☆: Supported in part by Research to Prevent Blindness, Inc, New York, New York.

¹: The authors have no proprietary interest in the Ahmed Glaucoma Valve implant.

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Original ArticlesIntermediate-term clinical experience with the Ahmed Glaucoma Valve implant 1☆,

Abstract

Section snippets

Patients and methods

Results

Discussion

Ophthalmology

Ophthalmology

Ophthalmology

Am J Ophthalmol

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Am J Ophthalmol

Ophthalmology

Ophthalmology

Am J Ophthalmol

Setons in glaucoma surgery

Implants in glaucoma surgery

Original Articles
Intermediate-term clinical experience with the Ahmed Glaucoma Valve implant 1☆,