OBJECTIVE: To evaluate the recently published literature on the efficacy and safety of the use of aqueous shunts with extraocular reservoir for the management of adult open-angle glaucomas (OAGs).
METHODS: A search of peer-reviewed literature was last conducted in April 2023 of the PubMed database and included only articles published since the last aqueous shunt Ophthalmic Technology Assessment, which assessed articles published before 2008. The abstracts of these 419 articles were examined, and 58 studies were selected for full-text analysis. After inclusion and exclusion criteria were applied, 28 articles were selected and assigned ratings by the panel methodologist according to the level of evidence. Twenty-five articles were rated level I and 3 articles were rated level II. There were no level III articles.
RESULTS: Implantation of aqueous shunts with extraocular reservoir can lower intraocular pressure (IOP) by between one-third and one-half of baseline IOP, depending on whether it is undertaken as the primary or secondary glaucoma surgery. Success rates for aqueous shunts were found to be better than for trabeculectomies in eyes with prior incisional surgery. Conversely, in eyes without prior incisional surgery, implantation of aqueous shunts was found to have an overall lower success rate as the primary glaucoma procedure compared with trabeculectomy. Although both valved and nonvalved aqueous shunts with extraocular reservoir were effective, the nonvalved device generally achieved slightly lower long-term IOPs with fewer glaucoma medications and less need for additional glaucoma surgery. Both devices slow the rates of visual field progression with efficacy comparable with that of trabeculectomy. Early aqueous humor suppression after aqueous shunt implantation is recommended for the management of the postoperative hypertensive phase and long-term IOP control. No strong evidence supports the routine use of mitomycin C with aqueous shunt implantation for OAG.
CONCLUSIONS: Implantation of aqueous shunts with extraocular reservoir, including valved or nonvalved devices, has been shown to be an effective strategy to lower IOP. Strong level I evidence supports the use of aqueous shunts with extraocular reservoir by clinicians for the management of adult OAG.
BACKGROUND: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

OBJECTIVE: To assess practice patterns and opinions of glaucoma specialists regarding indications, surgical technique, and postoperative management for nonvalved aqueous shunts.
METHODS: Anonymous online survey study.
METHODS: American Glaucoma Society (AGS) members.
METHODS: An anonymous online survey was distributed to glaucoma specialists via the AGS forum from June to August 2022.
METHODS: Survey questions and responses were assessed in 4 sections: (1) general demographics and practice patterns; (2) nonvalved tubes vs. trabeculectomy; (3) nonvalved tubes vs. valved tubes; and (4) nonvalved tube techniques.
RESULTS: There were 132 respondents; nonvalved tubes were reported to be performed more often than trabeculectomy by 61% of respondents within 5 years of completing training and 23% of respondents with more than 15 years since completing training. The most frequently preferred types of nonvalved tubes were Baerveldt-350 (41%), Baerveldt-250 (27%), and ClearPath-250 (18%). In patients with lower target intraocular pressure (IOP), 92% of respondents preferred trabeculectomy over nonvalved tube; 33% cited a cutoff of < 12 mmHg, and 31% cited a cutoff of < 15 mmHg. In patients with higher preoperative IOP, 50% of respondents preferred valved over nonvalved tubes; 29% cited a cutoff of > 40 mmHg, and 38% cited a cutoff of > 30 mmHg. The most frequently used ligature was 7-0 Vicryl (69%). The most frequently used strategies for early IOP lowering were fenestrations without wicks (70%) and with wicks (22%), with one 10-0 Nylon being the most used wick technique (22%). Overall, 37% of respondents use a ripcord; among ripcord users, 55% use it for hypotony prevention (3-0 Prolene most common for this purpose at 35%), and 40% use it for optional early IOP lowering (4-0 Nylon most common for this purpose at 21%). If IOP is too high at postoperative week 4, 38% of respondents do not open the tube early.
CONCLUSIONS: We demonstrate significant heterogeneity regarding specific indications, surgical technique, and postoperative management for nonvalved tubes. Future work is needed to identify and develop standardized guidelines alongside best practices.
BACKGROUND: The author(s) have no proprietary or commercial interest in any materials discussed in this article.

OBJECTIVE: To describe the technique and demonstrate the utility and outcomes of using a thick 3-0 Prolene ripcord in the lumen of a Baerveldt-350 aqueous shunt until after the ligature suture dissolves.
METHODS: Single-center, noncontrolled, retrospective case series.
METHODS: A total of 50 eyes from 50 patients with glaucoma undergoing placement of Baerveldt-350 aqueous shunts with 3-0 Prolene ripcords.
METHODS: A retrospective chart review was performed for all eyes of adult patients that had undergone a Baerveldt-350 aqueous shunt placement by a single surgeon at a single academic center between October 1, 2019 and June 30, 2022.
METHODS: Data collected included demographic and clinical characteristics of the patients, preoperative and postoperative clinical data including intraocular pressure (IOP) and glaucoma medications, postoperative timepoints of ligature suture dissolution, and timepoints of 3-0 Prolene ripcord removal or whether they were permanently left in place.
RESULTS: In total, 50 eyes from 50 patients were included; mean age was 69.5 years, 54.0% of patients were female, 92% of patients were Black, and 66% of eyes had primary open-angle glaucoma. Twenty-six of 50 (52%) eyes had ripcord removal at the soonest postoperative visit after spontaneous ligature dissolution, 19/50 (38%) eyes had delayed ripcord removal, and 5/50 (10%) eyes had no ripcord removal. There were no cases of hypotony-associated complications (shallow anterior chamber, hypotony maculopathy, choroidal effusion, suprachoroidal hemorrhage) in this subgroup of eyes that underwent no ripcord removal.
CONCLUSIONS: Our results demonstrate that routine use of a 3-0 Prolene ripcord to partially occlude the lumen of a Baerveldt-350 is a useful strategy to minimize sudden hypotony-associated complications when the ligature suture dissolves. This strategy allows for a more controlled postoperative course and a safe 2-step decrease in IOP (1: when the ligature dissolves, and 2: when the ripcord is removed).
BACKGROUND: The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Purpose  The aim of the study is to report changes in tube shunt placement surgical case times for glaucoma fellows during the course of the academic year. Patients and Methods  Electronic health records were retrospectively reviewed to determine patient demographics, surgical case times (defined as procedure start time to procedure end time), and glaucoma fellow involvement. Only cases with a glaucoma fellow as the primary surgeon were included. Operative case times were compared by first and second halves of the academic year (beginning in July and ending in June) using a two-tailed t -test. Results  Five hundred and seventy-three individual tube shunt surgeries (385 Ahmed, 188 Baerveldt) performed by 28 glaucoma fellows (17 females, 11 males) at Duke University Eye Center and University of North Carolina Medical Center were included. Overall, case times were significantly shorter in the second half of the academic year as compared with the first (55.3 ± 17.1 minutes vs. 61.0 ± 17.4 minutes, p <0.001). Both male (57.3 ± 16.8 minutes vs. 63.2 ± 18.6 minutes, p  = 0.008) and female (53.5 ± 17.3 minutes vs. 59.3 ± 16.4 minutes, p  = 0.003) fellows demonstrated shorter case times over the academic year; additionally, female fellows trended toward shorter case times than male fellows in both the first half ( p  = 0.072) and second half ( p  = 0.053) of the academic year. Fellows also exhibited shorter case times with both Ahmed implants (54.1 ± 16.2 minutes vs. 59.3 ± 15.8 minutes, p  = 0.002) and Baerveldt implants (57.8 ± 18.9 minutes vs. 64.2 ± 20.0 minutes, p  = 0.025) cases over the academic year. Baerveldt case times were significantly longer than Ahmed cases in the first half ( p  = 0.028) and trended toward being longer than Ahmed cases in the second half ( p  = 0.070). Conclusion  Across 5 years at two academic institutions, glaucoma fellows had shorter primary tube shunt surgical case times in the second half of the academic year. These findings reflect improvement in surgical efficiency throughout glaucoma fellowship. These findings should be taken into consideration when scheduling trainee surgeries at academic medical centers at different points in the academic year.

UNASSIGNED: This study investigates the effect of one versus two fenestrations on both fluid egress and opening pressure from a non-valved glaucoma implant.
UNASSIGNED: In this laboratory study, we used an in vitro closed system comprised of ligated silicone tubing connected to a fluid reservoir and manometer to simulate the tubing found in a Baerveldt glaucoma drainage implant. Fenestrations were created using an 8-0 Vicryl TG140-8 suture needle. Main outcome measures included volume of fluid egress and fenestration opening pressures, which were measured via micropipette and increasing pressure until fluid egress was observed.
UNASSIGNED: No significant difference was observed in fluid egress between tubing with one versus two fenestrations at pressures ≤40 mmHg. At 50 mmHg, a statistically significant difference was observed in fluid egress between tubing with one versus two fenestrations (P < 0.05). The first fenestration opened at 10.5 ± 3.77 mmHg and the second fenestration opened at 28.83 ± 5.09 mmHg (average ± standard deviation).
UNASSIGNED: Our in vitro findings suggest there may exist a critical pressure >40 mmHg at which the second fenestration starts to play a significant role in fluid drainage. There may be no difference in the amount of fluid egress and effect on intraocular pressure between one or two tube fenestrations when preoperative intraocular pressure is ≤40 mmHg.

To describe a surgical variant for non-valved glaucoma drainage device implants using an easily removable non-absorbable double suture into the lumen of the tube. A retrospective, non-comparative case series of 10 patients who underwent a non-valved glaucoma drainage device implant with an endoluminal double-suture for refractory glaucoma. The sutures were easily removed postoperatively without the need for an operating room. Intraocular pressure, number of medications, and early and late complications were evaluated with a follow-up of 12 months. None of the eyes that underwent an operation developed early or late complications. The first endoluminal suture was removed in all eyes with a mean time of removal of 30 ± 7 days. The second suture was removed in all eyes with a mean time of removal of 90 ± 7 days. No complications were noted, either, after or during suture removal. The mean preoperative IOP was 27.3 ± 4.0 and the postoperative IOP, at the end of the follow-up, was 12.7 ± 1.4. At the end of the follow-up, six patients (60%) achieved complete success and four patients (40%) achieved qualified success. In conclusion, in our case series, the surgical variant allowed for a safe and gradual regulation of the flow during postoperative management. Considering the efficacy of non-valved glaucoma drainage devices, an improvement in the safety profile allows surgeons to broaden the surgical indications.

Glaucoma is one of the leading causes of blindness in the world. It is an ocular disorder that may have multiple etiologies and which can present as optic neuropathy and increased intraocular pressure (IOP), but in some cases like normotensive glaucoma, the IOP may remain normal. Its gradually progressive nature makes it important for early diagnosis; although the loss of vision is slow, lost vision can\'t be restored. Glaucoma drainage implant surgeries are an increasingly popular option in recent days in complicated cases of glaucoma where the previous trabeculectomy had failed and medical management was not responsive. Glaucoma drainage devices (GDD) are of various designs; they are implanted according to the patient condition and surgeons\' preference. There are complications after the implantation of a GDD like hypotony, endophthalmitis, migration of the plate, extrusion, erosion of the mucous membrane, etc. In the market, there are various drainage devices present, but some of them are frequently used and popular. In this article, we will discuss some most commonly used GDDs and their complications. Among these, four are the most popular: Molteno, Baerveldt, Krupin, and Ahmed. The failure rate of the GDD is low. In many studies, it has been noted that only half of the GDD remains functional after five years. Therefore, further studies are still being conducted to refine the biomaterials, techniques, and shape of the GDD. The technique of surgery is also very much crucial in the success of GDD implantation. The glaucoma type is an essential factor in deciding the treatment, and the outcome of the surgery also depends on it.

Purpose Variation among aqueous humor outflow from venting slits performed on glaucoma drainage device tubing often occurs even when physician technique and equipment are held constant. Our hypothesis is that there are dimensional differences within the tubing, even among the same make and model of glaucoma drainage device (GDD) implants. Methods Prior to surgical implantation, excess glaucoma drainage tubing was collected for analysis. The tubing samples were sliced horizontally, and the external tube, internal lumen, and wall dimension measurements were collected microscopically. Groups were divided based upon brand and model and then statistically analyzed using an independent t-test. A total of 28 tubes were analyzed, consisting of 7 Molteno and 21 Baerveldt implants. Results The mean external diameter for the Molteno group was 656 ± 20µm, significantly larger than the Baerveldt external diameter of 620 ± 13µm (P<0.05). The mean internal diameter among Molteno lumens was 344 ± 13µm, also statistically larger than the mean internal diameter of 309 ± 18µm for Baerveldt tubes (P<0.05). The Molteno luminal wall width varied significantly less than the Baerveldt wall, 18% versus 28%, respectively (P<0.05). The tubings\' wall widths variation translated into highly significant off-centered lumens among both brands. Conclusion Our findings suggest that there are significant variations among glaucoma implant dimensions between and within the multiple makes and models. The discrepancies among tubal wall thickness and off-centered lumens are undetectable to the naked eye. Importantly, this may result in significant aqueous humor outflow variation following the creation of venting slits secondary to the found irregular luminal diameters and tube wall thicknesses.

OBJECTIVE: To compare outcomes of glaucoma drainage device (GDD) implantation and trabeculectomies with and without postoperative intravitreal injections (IVIs) in glaucoma patients with a history of preoperative IVIs.
METHODS: Retrospective cohort study.
METHODS: A total of 133 eyes of 133 glaucoma patients who underwent GDD implantation or trabeculectomy with at least 1 IVI preoperatively between January 2005 and October 2020 at Massachusetts Eye and Ear.
METHODS: Chart review of glaucoma patients with traditional glaucoma surgery and at least 1 IVI before surgery. All statistical analyses were conducted with R statistical programming software.
METHODS: Intraocular pressure (IOP), medication burden, best-corrected visual acuity (BCVA), Kaplan-Meier success rates, adjusted hazard ratios (HRs), and complications.
RESULTS: Baseline demographics were similar between the groups with and without postoperative IVIs. The group with postoperative IVIs had a higher proportion of diabetic retinopathy and retinal vascular occlusions than the group without postoperative IVIs, which had more eyes with age-related macular degeneration. Intraocular pressure, medication burden, and visual acuity were similar between groups at all time points except for IOP at 6 weeks, which was lower in the group with postoperative IVIs. The group with postoperative IVIs had significantly more preoperative IVIs than the group without postoperative IVIs (6.6 vs. 3.3, P = 0.017). For success defined as IOP reduction ≥ 20% with 5 < IOP ≤ 21 mmHg, Kaplan-Meier analyses demonstrated similar success rates between groups with and without IVIs. When stratified by the number of IVIs, success rates for the group with 7 or more IVIs were significantly higher than the success rates for the group with 0-6 IVIs (P = 0.005). Each additional postoperative IVI resulted in a 7.2% decrease in the hazard of failure to achieve our stated success criteria. With regard to late complications, the group with postoperative IVIs had a higher incidence of vitreous hemorrhage (18.5% vs. 3.2%, P = 0.039) than the group without postoperative IVIs.
CONCLUSIONS: A higher number of postoperative IVIs, specifically 7 or more IVIs, may be associated with improved success rates of traditional glaucoma surgery in glaucoma patients who received IVIs before surgery.

OBJECTIVE: To report outcomes and follow-up of Baerveldt implant surgery in dogs with primary closed-angle glaucoma (PCAG).
METHODS: Record review of client-owned dogs with PCAG that underwent Baerveldt implant surgery during a 6-year period. Postoperative intraocular pressure (IOP), vision and daily number of anti-glaucoma drops at fixed time points (3, 12, and 24 months) were compared with preoperative values; complications were recorded. Success was defined as IOP <20 mm Hg and a positive menace response and navigation/tracking ability.
RESULTS: Twenty eyes (17 dogs) were included. Mean follow-up was 575 days (range 30-1767 days) from implant surgery to last examination. Three months postoperatively 15/20 (75%) eyes had IOP <20 mm Hg and 14/20 (70%) eyes had vision. Twelve months postoperatively 11/17 (65%) eyes had IOP <20 mm Hg and 12/19 (63%) eyes had vision. Twenty-four months postoperatively 8/14 (57%) eyes had IOP <20 mm Hg and 7/15 (47%) eyes had vision. Denominators differ between time points as eyes were included when duration after surgery reached the relevant postoperative time point or failure was documented earlier. Within 3 months postoperatively 16/20 (80%) eyes had ≥1 complication, including transient IOP >20 mm Hg (14/20; 70% eyes), fibrin (12/20; 60% eyes), and hypotony (4/20; 20% eyes). After 3 months, postoperatively 13/16 (81%) eyes had ≥1 complication, including cataracts (13/16; 81% eyes), bleb fibrosis (3/16; 19% eyes), and conjunctival wound breakdown (1/16; 6% eyes). One patient (1 eye) was euthanized for blindness and 5/20 (25%) eyes were enucleated.
CONCLUSIONS: The technique was effective in controlling IOP and maintaining vision in most dogs in this study.