Motility disturbances in the tube versus trabeculectomy study during the first year of follow-up

Two different types of giant bleb formation following Ahmed Glaucoma valve implantation

Purpose

This study aims to present two different types of giant bleb formation following Ahmed Glaucoma Valve (AGV) implantation: an anterior enlarged giant bleb and a posterior enlarged giant bleb.

Observations

In Case 1, a 70-year-old Japanese male underwent AGV implantation for neovascular glaucoma in his right eye (OD). Preoperatively, the patient's intraocular pressure (IOP) and best corrected visual acuity (BCVA) were 23 mmHg and 0.6, respectively, OD, while using 3 antiglaucoma topical medications. Two months post-surgery, the patient began experiencing double vision. Slit lamp evaluation revealed no abnormalities, IOP and BCVA were 24.0 mmHg and 0.8, respectively, OD. A posteriorly enlarged bleb in the superotemporal quadrant OD was found to be causing displacement on T2-weighted orbital MRI. The patient underwent surgical excision of the anterior bleb wall. By three weeks post-surgery, the double vision resolved; IOP and BCVA were 17 mmHg and 0.7, respectively, and a normal bleb in the slit lamp evaluation was identified OD. In Case 2, a 10-year-old Japanese female underwent AGV implantation for childhood glaucoma associated with congenital cataract OD. Preoperatively, IOP and BCVA were 30 mmHg and 0.5, respectively, OD, while using 3 antiglaucoma topical medications. She underwent pars plana vitrectomy (PPV) in addition to AGV implantation. Seven months post-surgery, slip lamp evaluation revealed an anteriorly enlarged giant bleb that only cause her a cosmetic concern.

Conclusions and Importance

There are two types of giant bleb formation following AGV implantation based on the direction of the enlargement: an anterior enlarged giant bleb and a posterior enlarged giant bleb. The introduction of this classification contribute to better understanding and management of this unusual surgical complication.

Postoperative Complications in the Primary Tube Versus Trabeculectomy Study During 5 Years of Follow-up

PURPOSE

To describe postoperative complications encountered in the Primary Tube Versus Trabeculectomy (PTVT) Study during 5 years of follow-up.

DESIGN

Multicenter randomized clinical trial.

PARTICIPANTS

A total of 242 eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 patients in the tube group and 117 patients in the trabeculectomy group.

METHODS

Patients were enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC, 0.4 mg/ml for 2 minutes).

MAIN OUTCOME MEASURES

Surgical complications, reoperations for complications, visual acuity, and cataract progression.

RESULTS

Early postoperative complications occurred in 24 patients (19%) in the tube group and 40 patients (34%) in the trabeculectomy group (P = 0.013). Late postoperative complications developed in 27 patients (22%) in the tube group and 32 patients (27%) in the trabeculectomy group (P = 0.37). Serious complications producing vision loss and/or requiring a reoperation were observed in 3 patients (2%) in the tube group and 9 patients (8%) in the trabeculectomy group (P = 0.11). Cataract progression was seen in 65 patients (52%) in the tube group and 52 patients (44%) in the trabeculectomy group (P = 0.30). Surgical complications were not associated with a higher rate of treatment failure (P = 0.61), vision loss (P = 1.00), or cataract progression (P = 0.77) CONCLUSIONS: A large number of surgical complications were observed in the PTVT Study, but most were transient and self-limited. The incidence of early postoperative complications was higher following trabeculectomy with MMC than with tube shunt surgery. The rates of late postoperative complications, serious complications, and cataract progression were similar with both surgical procedures after 5 years of follow-up. Surgical complications did not increase the risk of treatment failure, vision loss, or cataract progression.

Magnetic resonance imaging reveals possible cause of diplopia after Baerveldt glaucoma implantation

Purpose

To assess if ocular motility impairment, and the ensuing diplopia, after Baerveldt Glaucoma device (BGI) implantation, is related to the presence of a large fluid reservoir (bleb), using Magnetic Resonance Imaging (MRI).

Methods

In a masked observational study (CCMO-registry number: NL65633.058.18), the eyes of 30 glaucoma patients with (n = 12) or without diplopia (n = 18) who had previously undergone BGI implantation were scanned with a 7 Tesla MRI-scanner. The substructures of the BGI-complex, including both blebs and plate, were segmented in 3D. Primary outcomes were a comparison of volume and height of the BGI-complex between patients with and without diplopia. Comparisons were performed by using an unpaired t-test, Fisher’s Exact or Mann-Whitney test. Correlations were determined by using Spearman correlation.

Results

The median volume and height of the BGI-complex was significantly higher in patients with compared to patients without diplopia (p = 0.007 and p = 0.025, respectively). Six patients had an excessively large total bleb volume (median of 1736.5mm³, interquartile range 1486.3–1933.9mm³), four of whom experienced diplopia (33% of the diplopia patients). Fibrotic strands through the BGI plate, intended to limit the height of the bleb, could be visualized but were not related to diplopia (75% versus 88%; p = 0.28).

Conclusions

With MRI, we show that in a significant number of diplopia cases a large bleb is present in the orbit. Given the large volume of these blebs, they are a likely explanation of the development of diplopia in at least some of the patients with diplopia after BGI implantation. Additionally, the MR-images confirm the presence of fibrotic strands. As these strands are also visible in patients with a large bleb, they are apparently not sufficient to restrict the bleb height.

The surgical management of glaucoma: A review

After a long period of little change, glaucoma surgery has experienced a dramatic rise in the number of possible procedures in the last two decades. Glaucoma filtering surgeries with mitomycin C and glaucoma drainage devices remain the standard of surgical care. Other newer surgeries, some of which are minimally or microinvasive glaucoma surgeries, target existing trabecular outflow, enhance suprachoroidal outflow, create subconjunctival blebs, or reduce aqueous production. Some require the implantation of a device such as the iStent, Hydrus, Ex-PRESS, XEN and PRESERFLO, whilst others do not-Trabectome, Kahook dual blade, Ab interno canaloplasty, gonioscopy-assisted transluminal trabeculotomy, OMNI and excimer laser trabeculotomy. Others are a less destructive variation of an established procedure, such as micropulse transscleral cyclophotocoagulation, endoscopic cyclophotocoagulation and ultrasound cycloplasty. Cataract surgery alone can be a significant glaucoma operation. These older and newer glaucoma surgeries, their mechanism of action, efficacy and complications are the subject of this review.

Ocular motility changes and diplopia in sutured versus unsutured implantation of the Baerveldt glaucoma device

Purpose

To investigate the effect of two surgical techniques in primary Baerveldt glaucoma implant (BGI) surgery, that is the sutured technique and the unsutured (free) plate technique, on the ocular motility and prevalence of diplopia. We hypothesize that the free plate technique results in a lower diplopia prevalence.

Methods

We performed a prospective study of patients who underwent BGI surgery with the free plate technique and compared them with patients from a previous study who had undergone BGI surgery with the sutured technique. Their ductions, ocular alignment and fusion range and the prevalence of diplopia were measured before surgery and at 3 months, 6 months and 1 year postoperatively.

Results

We analysed 57 free plate and 51 sutured plate patients. One year postoperatively, we found no statistically significant difference in the prevalence of diplopia between the two techniques. All duction changes between baseline and 1‐year follow‐up were restrictions and occurred statistically significantly more frequently in the free plate than in the sutured plate group (p = 0.03; 60% versus 34%). About the ocular alignment, in the horizontal direction, a change in exodirection was more common in both groups, while in the vertical direction, a hyperdeviation of the operated eye was more common. The vertical ocular alignment change was smaller in the free plate group than in the sutured plate group (p = 0.04 at near and p = 0.02 at distance).

Conclusions

One year postoperatively, the prevalence of diplopia was not significantly different between patients with the sutured plate and patients with the free plate technique. Both surgical techniques induce diplopia and changes in ocular motility and/or in ocular alignment.

Rates of Diplopia in Ahmed FP7, Baerveldt 250, and 350 Glaucoma Patients Compared With Medical Controls

PRECIS

Diplopia was present in ~20% of patients with Ahmed FP7 (FP7) or Baerveldt 350 (B350), compared with 5% to 6% in those with Baerveldt 250 (B250) or controls, suggesting risk of diplopia should be included in preoperative counseling.

PURPOSE

The purpose of this study was to examine the prevalence of diplopia and strabismus in patients with B250, B350, or FP7 glaucoma drainage devices (GDD).

MATERIALS AND METHODS

In this cohort study, glaucoma patients 18 years and above who had received, or would be receiving, a B250, B350, or FP7 GDD, and medically treated controls were consecutively enrolled from August 8, 2017, through July 31, 2019. The Diplopia Questionnaire was administered ≥30 days postoperatively, and upon enrollment to the controls. All diplopic patients underwent orthoptic measurements, which were reviewed by a strabismus specialist. Patients with GDDs in quadrants other than superotemporal, multiple GDDs, or scleral buckles were excluded. Bonferroni correction was applied for pairwise comparisons.

RESULTS

Diplopia was reported in 23/129 (17.8%) GDD patients and 5/99 (5.1%) control patients (P=0.003): 8/35 (22.9%) FP7, 2/32 (6.3%) B250, and 13/62 (21.0%) B350, with significant differences between FP7 versus controls (P=0.014) and B350 versus controls (P=0.011). Diplopia was attributable to GDD in 2 FP7 (5.9%, 95% confidence interval: 0.7-19.2), 0 B250, and 4 B350 (6.5%, 95% confidence interval: 1.7-15.2) patients, without significant differences between the GDDs.

CONCLUSIONS

Patients with the larger (B350) or the higher profile plate (FP7) GDDs were more likely to experience diplopia than controls, and diplopia was attributable to the GDD in ~6% of patients with either a FP7 or a B350 GDD. Since diplopia can affect patients' quality of life, preoperative counseling for GDD surgery, particularly B350 and FP7, should include a discussion of the risk of diplopia.

Orbital anatomy magnetic resonance imaging in diplopic versus non-diplopic patients after glaucoma drainage device placement

PURPOSE

New-onset persistent diplopia has become a common complication after glaucoma drainage device (GDD) placement. Understanding the orbital anatomy of such patients may provide information regarding risk of diplopia, GDD selection, and post-operative management. The purpose of this study was to examine the orbital anatomic differences in diplopic and non-diplopic patients after GDD implantation using high-resolution MRI.

METHODS

Seven eyes (N = 4 with diplopia and N = 3 without diplopia after GDD placement) of seven patients that had undergone placement of Baerveldt 250 (B250), Baerveldt 350 (B350), or Ahmed FP7 (FP7) GDD were prospectively enrolled at a single institution. All patients underwent a 3.0T orbital MRI with 3D volumetric T1 and T2 weighted sequence. Images were analyzed for orbital volume, axial length, orbital distances, presence of superior rectus-lateral rectus (SR-LR) band, position of GDD, and SR-LR angles.

RESULTS

Patients with diplopia had smaller mean ± SD orbital axial (911.5 ± 111.8 mm³ vs 931.7 ± 79.7 mm³) and coronal volumes (1162.5 ± 145.5 mm³ vs 1180 ± 34.6 mm³) compared to non-diplopic patients. Average orbital rim distances were larger for the diplopic group. The SR-LR displacement angle for diplopic patients was larger (101.6° ± 8.1 vs 94.7° ± 17.6) while the SR-LR quadrantic angle (86.6° ± 4.2 vs 89.1° ± 4.3) was smaller. SR-LR band was present and intact in all patients. GDD malpositioning was not evident in any patient.

CONCLUSION

The decreased orbital axial and coronal volumes as well as increased orbital rim distances in diplopic patients suggests the need for further studies to understand the role of orbital anatomy in occurrence of diplopia. Dynamic MRI imaging may be helpful in identifying differences in extraocular muscle function that reveal an etiology of diplopia in patients with GDD implantation.

Occurrence of motility disorders in patients undergoing tube surgery-consecutive, retrospective follow-up case series analysis

BACKGROUND

The two glaucoma drainage devices (GDD) Ahmed and Baerveldt tubes are most commonly used for the treatment of refractory glaucoma. We noticed a significant number of patients with postoperative motility disorders resulting in diplopia. We investigated the occurrence and patterns of postoperative motility disorders overall and between the two GDD tubes using the Hess Screen Test.

METHODS

Retrospective single-center matched case series of 20 patients undergoing Ahmed and 20 patients undergoing Baerveldt tube implantation with a follow-up of at least 1 year. In order to investigate the dynamic of GDD-induced motility disorder over time, from 25 patients, a follow-up examination from two different time periods (3 to 6 months and 12 to 24 months postoperatively) was available. From these 25 patients, 12 had received an Ahmed and 13 a Baerveldt GDD. To compare the different Hess Screen Tests, we developed nine categories of possible emerging motility disorder in the operated eye as a primary endpoint: Motility restriction in up-gaze, in down-gaze, in abduction, in adduction; combined motility disorders in up-gaze and adduction, up-gaze and abduction, down-gaze and adduction, down-gaze and abduction. If there was no motility disorder, this was also separately classified.

RESULTS

Regardless of the used device, Ahmed or Baerveldt, most patients experienced motility disorders to some extent; mainly down-gaze and adduction were affected. However not every motility disorder resulted in diplopia. Although over time a decrease in ocular misalignment was seen, the incidence of diplopia was stable. Nevertheless, only few required therapy. We noted no difference between Ahmed and Baerveldt tube implant devices.

CONCLUSION

Ocular misalignment and restriction of motility is a common finding after GDD. Although not every motility disorder results in diplopia, it is frequent. Therefore, it needs to be taken into consideration in informed consent.

The Tube Versus Trabeculectomy IRIS® Registry Study: Cohort Selection and Follow-up and Comparisons to the Randomized Controlled Trial

PURPOSE

To assess the feasibility of replicating a randomized controlled trial (RCT) with a cohort of eyes, from IRIS® Registry data, analogous to the Tube Versus Trabeculectomy (TVT) RCT cohort and compare characteristics and follow-up.

DESIGN

Comparison of RCT and IRIS Registry cohorts and follow-up.

METHODS

We identified a cohort of IRIS Registry eyes (2013-2017) that received either a glaucoma drainage implant (tube) or trabeculectomy after a previous trabeculectomy and/or cataract extraction; extracted clinical and demographic characteristics for baseline surgery and follow-up visits through 1 year; and compared treatment groups in the IRIS Registry cohort and this cohort to the TVT RCT cohort.

RESULTS

The IRIS Registry cohort included 419 eyes: 183 (43.7%) trabeculectomy; 236 (56.3%) tube. There were significant differences between treatment groups, including race (White: trabeculectomy 61.8%, tube 44.9%; Black: trabeculectomy 20.8%, tube 35.6%; P = .003) and the percentage of follow-up visits completed (trabeculectomy 88.4%, tube 83.8%, P = .004). There were also significant differences between the TVT IRIS Registry cohort and the TVT RCT cohort in the percentage of follow-up visits completed (IRIS Registry 85.6%, RCT 96.1%, P < .001) and in the probability of having a 1-year follow-up visit (IRIS Registry 81.4%, RCT 89.2%, P = .011).

CONCLUSION

The TVT IRIS Registry cohort had several significant treatment group differences at baseline, whereas there had been none in the TVT RCT cohort. Follow-up in the TVT IRIS Registry cohort was inferior to that of the TVT RCT. Some data needed to refine the selection of eyes for the cohort were not available in the IRIS Registry.

Evaluation of Diplopia Secondary to Seton Implantation Surgery: Ahmed Glaucoma Valve and Diplopia

Objectives:

To determine and evaluate the rate of diplopia after Ahmed glaucoma valve (AGV) implantation surgery.

Materials and Methods:

The records of patients who underwent AGV implantation in our hospital between the years of 2010 and 2017 were retrospectively reviewed. Patients who were referred to our strabismus department due to binocular diplopia after AGV implantation surgery were included. The details of postoperative day 1, day 7, day 15, and 1 month examinations were recorded. In the postoperative period, the onset time of diplopia complaints, diplopia type, and the presence of diplopia at distance and near fixation were noted. Ocular motility examination and deviation measurements were evaluated.

Results:

Ten (47%) of 211 patients who underwent AGV implantation in our hospital between 2010 and 2017 met the study inclusion criteria. Six of the 10 patients were men (60%) and 4 were women (40%). The mean age of the patients was 44.5 (34-63) years. Complaints of diplopia developed at a mean of 14.5±12.3 (1-30) days after AGV implantation. The prism measurements of the patients were found to be 8.4±1.4 prism diopters (PD) exotropia and 7.1±8.8 PD hypotropia. While 8 patients had diplopia only at near distance, 2 patients had diplopia at both distance and near. Three patients were treated with prismatic glasses, and their complaints of diplopia recovered spontaneously in 5.11±4.10 months. The other 7 patients were followed up without treatment, and their diplopia complaints resolved spontaneously in 6.11±4.40 months.

Conclusion:

Although most of the diplopia that develops after AGV implant surgery resolves without treatment, prismatic glasses might be considered as a treatment option in patients whose diplopia affects their daily lives.

Strabismus After Ahmed Glaucoma Valve Implantation

PURPOSE

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.

DESIGN

Retrospective review.

METHODS

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.

RESULTS

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).

DISCUSSION

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.

Management of strabismus related to infantile glaucoma: Case series

OBJECTIVE

To evaluate the different modalities of treatment of the strabismus related to infantile glaucoma, its complications, and results.

METHODS

The clinical history of 7 patients with infantile glaucoma which required strabismus surgical treatment were analyzed. Age at onset of glaucoma, type of glaucoma, glaucoma surgeries, type of strabismus, strabismus surgical treatment and postoperative results were studied.

RESULTS

Four patients required strabismus surgery, two were treated with botulinum toxin and one required both. Primary congenital glaucoma was the most common (71,42%), 14,28% had an anterior segment dysgenesis and 14,28% had secondary glaucoma. Regarding strabismus, 4 patients had exotropia and 3 had esotropia. The main difficulty involved the management of the conjunctiva and the filtering blebs.

CONCLUSION

Strabismus is a frequent complication in infantile glaucoma. The management of these patients should be individualized. In our case series, treatment of strabismus improved eye alignment. Surgery should be the mainstay of treatment while preserving the conjunctiva and interfere the less with glaucoma surgeries. Botulinum toxin is a reasonable option when conservative treatment is needed.

Health-related quality of life in Ahmed FP7, and Baerveldt 250 and 350 patients compared with medical controls

PURPOSE

To compare health-related quality of life (HRQoL) in patients with Ahmed FP7 (FP7), Baerveldt 250 (B250) and Baerveldt 350 (B350) glaucoma drainage device (GDDs), and medically treated controls.

METHODS

This was a prospective cohort study from August 2017 to July 2019. The NEI 25-Item Visual Function Questionnaire (VFQ-25), the Adult Strabismus-20 questionnaire (AS-20) and the Diplopia Questionnaire were conducted ≥30 days postoperatively in GDD patients, on enrolment for controls. Age, sex, treatment type, visual acuity, mean deviation and diplopia were evaluated for association with HRQoL RESULTS: Of the 128 GDD patients enrolled, 35 (27.3%) had FP7, 32 (25.0%) had B250 and 61 (47.7%) had B350. In univariate analysis, decreased HRQoL was associated with younger age (r² range 0.042-0.071), diplopia (r² range 0.039-0.119), GDD treatment (r² range 0.023-0.103), lower visual acuity (r² range 0.021-0.215) and worse mean deviation (r² range 0.029-0.131). All GDD groups had lower HRQoL subscores than the controls. HRQoL scores were lower compared with controls among B350 patients for AS-20 Self-perception subscale, B250 and B350 for Reading and General Function subscales, and FP7 and B350 for VFQ-25 Visual Functioning subscale. There were no significant differences among the GDDs.

CONCLUSIONS

Glaucoma patients with a younger age, diplopia, lower visual acuity, worse mean deviation or a GDD had lower HRQoL. Those with B350 had lower self-perception scores, consistent with previous reports in the literature. This subscale was not diminished in FP7 or B250, so the decreased self-perception scores may be due to greater visibility or awareness of the B350.

Management of strabismus related to infantile glaucoma: Case series

OBJECTIVE

To evaluate the different modalities of treatment of the strabismus related to infantile glaucoma, its complications, and results.

METHODS

The clinical history of 7 patients with infantile glaucoma which required strabismus surgical treatment were analyzed. Age at onset of glaucoma, type of glaucoma, glaucoma surgeries, type of strabismus, strabismus surgical treatment and postoperative results were studied.

RESULTS

Four patients required strabismus surgery, two were treated with botulinum toxin and one required both. Primary congenital glaucoma was the most common (71,42%), 14,28% had an anterior segment dysgenesis and 14,28% had secondary glaucoma. Regarding strabismus, 4 patients had exotropia and 3 had esotropia. The main difficulty involved the management of the conjunctiva and the filtering blebs.

CONCLUSION

Strabismus is a frequent complication in infantile glaucoma. The management of these patients should be individualized. In our case series, treatment of strabismus improved eye alignment. Surgery should be the mainstay of treatment while preserving the conjunctiva and interfere the less with glaucoma surgeries. Botulinum toxin is a reasonable option when conservative treatment is needed.

Removal of a Baerveldt Glaucoma Implant and Fibrous Adhesion for Refractory Mechanical Strabismus

Although strabismus is a well-known complication of glaucoma implant surgery, its surgical treatment is still challenging. We present a case with refractory strabismus after Baerveldt glaucoma implant (BGI) surgery, which was not sufficiently improved by strabismus surgery, but by removal of the BGI and fibrous adhesion. The patient was a 35-year-old woman who had multiple surgeries for secondary glaucoma. She had severe limitations of the movement of her right eye and binocular diplopia in all gaze positions after BGI surgery. Although she underwent two strabismus surgeries, the strabismus was not resolved. The surgery was performed by two specialists in glaucoma and strabismus. The BGI plate and the fibrous capsule were carefully removed. The fibrous tissue involved the muscle bellies of the inferior and particularly lateral rectus (LR) muscles and induced tight and wide adhesion between the muscle bellies and sclera. The adhesion was released after tenotomy at the insertion of the LR muscle, and the LR muscle was additionally resected by 6.0 mm. The ocular position and movement dramatically improved; however, intraocular pressure (IOP) increased immediately after the surgery. Then, Ahmed glaucoma valve implantation was performed 5 days after BGI removal. The IOP decreased and has been controlled. The improvement of ocular position and movement remained 9 months postoperatively and she obtained cosmetic satisfaction without diplopia or worsening of visual acuity. Removal of BGI and fibrous adhesion is a potential option for refractory mechanical strabismus following BGI surgery; however, it is important to prepare additional procedures for the subsequent IOP increase in advance.

Otago Glaucoma Surgery Outcome Study: Examining the Development of Strabismus Causing Diplopia in Patients Who Have Received Molteno Implant Surgery

OBJECTIVE

To evaluate the development of postoperative strabismus causing diplopia in patients who received Molteno implant surgery for the treatment of glaucoma.

METHODS

The Otago Glaucoma Surgery Outcome study (OGSOS) was used to select cases who had undergone Molteno implant surgery to examine the effect on the development of strabismus causing diplopia. Information was collected on treatments provided to correct motility disturbance, and their success, in this retrospective non-comparative study.

RESULTS

32 cases (3.3%) were found to have developed diplopia following the Molteno implant surgery from a total of 977 cases. Of these, the strabismus in 23 cases was described in sufficient detail to permit clinical categorization. Most (19/23) demonstrated an exodeviation, hyperdeviation, or a combination thereof, although 2/6 cases with superonasal plate location demonstrated a hypodeviation. Diplopia generally resolved spontaneously (20/32 cases). Treatment was required in eight cases, usually conservative and successful (6/8 cases), but strabismus surgery was required in two cases, and was unsuccessful.

CONCLUSIONS

This study found a low incidence of diplopia developing post-Molteno implant surgery. Strabismus features suggested a restrictive etiology, and spontaneous recovery was common (62.5%). Surgical correction proved unsuccessful - confirming persistent postoperative diplopia after Molteno implant surgery to be a rare but surgically challenging complication.

Risk factors for strabismus following glaucoma drainage device implantation for refractory childhood glaucoma

BACKGROUND

Strabismus is common in children after glaucoma drainage device (GDD) implantation, but the risk factors for postoperative strabismus remain speculative. The purpose of this study was to investigate possible risk factors for strabismus following GDD implantation for refractory childhood glaucoma.

METHODS

The medical records of consecutive patients who underwent GDD implantation for refractory childhood glaucoma at Duke Eye Center from 2005 to 2016 were reviewed retrospectively. Pre- and postoperative motility and alignment, best-corrected visual acuity, and demographic and surgical data were extracted from the record for analysis.

RESULTS

A total of 81 patients (mean age, 7.9 ± 4.8 years) met inclusion criteria. The most common glaucoma type was glaucoma following cataract surgery (GFCS), and the most common GDD was a Baerveldt 250 mm² device. Before GDD surgery, 38 patients (47%) had documented strabismus. After GDD implantation, 25 (31%) had new or worsened strabismus, with vertical (16% of new/worsened), horizontal strabismus (exotropia, 48% of new/worsened; esotropia, 12% of new/worsened) and vertical and horizontal (24% of new/worsened) noted. New motility limitation occurred in 32 of 81 (40%) patients. Risk factors including age, type/location/number of GDD, revision, motility limitation, glaucoma type, asymmetric visual acuity, and visual impairment were not significantly associated with new or worsened post-GDD strabismus.

CONCLUSIONS

Children with refractory childhood glaucoma are at high risk for strabismus, which increases after GDD implantation; this study identified no clear risk factors for new or worsened post-GDD strabismus.

Strabismus surgery in the setting of glaucoma drainage devices in the pediatric population

PURPOSE

To evaluate outcomes of strabismus surgery performed subequent to or concomitant with glaucoma drainage device (GDD) implantation for refractory childhood glaucoma.

METHODS

The medical records of children who underwent strabismus surgery after or concomitantly with GDD implantation were reviewed retrospectively. Included were surgeries with motility and alignment data measured preoperatively and ≥3 months postoperatively. The following data were collected: demographics, visual acuity, glaucoma diagnosis, GDD type/location, pre- and postoperative sensorimotor/alignment measurements, and surgical details. Motor success was defined as ≤10^Δ horizontal and ≤4^Δ vertical residual heterotropia postoperatively.

RESULTS

A total of 25 children were included: 11 in the post-GDD group and 14 in the concomitant-GDD group. In the former, peri-GDD capsule dissection was required in 9 of 11 patients (82%). All cases had preoperative motility restriction or intraoperative scarring. Mean preoperative deviation (26.7^Δ ± 14.6^Δ) decreased by 41% postoperatively, with improved alignment in 7 patients (64%). No patients met strict motor alignment criteria for success. In the concomitant-GDD group, mean preoperative deviation (28.5^Δ ± 10.0^Δ) decreased by 39% postoperatively, with improved alignment in 11 of 14 patients (79%). Four patients (29%) met strict criteria for success. There were no surgical complications in either group.

CONCLUSIONS

Strabismus surgery in eyes with existing or planned GDDs for childhood glaucoma usually improves alignment but often does not result in success based on strict motor alignment criteria. Eyes with childhood glaucoma pose surgical technical challenges related to small orbits and exuberant GDD capsule-muscle scarring and postoperative challenges of poor vision and limited binocular function, that likely limit succcess.

New developments in tube shunt surgery

PURPOSE OF REVIEW

This article reviews recent studies related to tube shunt surgery.

RECENT FINDINGS

Medical claims data and surveys of glaucoma surgeons demonstrate that tube shunts are being selected with increasing frequency as an alternative to trabeculectomy. A 5-year pooled analysis of the Ahmed Baerveldt comparison study and Ahmed versus Baerveldt study found a higher rate of surgical success with the Baerveldt glaucoma implant compared with the Ahmed glaucoma valve, but Baerveldt implantation carried a higher risk of hypotony. The primary tube versus trabeculectomy study showed trabeculectomy with mitomycin C produced greater intraocular pressure reduction with fewer glaucoma medications compared with tube shunt surgery as a primary procedure at 1 year, but trabeculectomy had a higher rate of postoperative complications. Adjunctive use of antifibrotic agents may enhance the success of tube shunt surgery. Implantation of a second tube shunt is effective in lowering intraocular pressure following primary tube shunt failure, but good results have also been reported with cyclophotocoagulation. Endothelial cell loss, diplopia, and tube shunt erosion are complications associated with these devices.

SUMMARY

The popularity of tube shunts has grown in recent years. Clinical trials and retrospective studies have provided valuable information to guide surgeons in the use of tube shunts. Increased efficacy of glaucoma procedures generally occurs at the cost of a higher risk of surgical complications.

Aqueous shunt versus trabeculectomy for treatment of glaucoma

INTRODUCTION

Aqueous shunt has emerged as an alternative technique to trabeculectomy, which is considered the standard treatment for glaucoma surgery. Currently, it is mainly indicated after failure of trabeculectomy or in some types of glaucoma with high risk of failure. However, there is still controversy regarding its effectiveness compared to trabeculectomy.

METHODS

We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach.

RESULTS AND CONCLUSIONS

We identified five systematic reviews including nine studies overall, of which four were randomized trials. We concluded that aqueous shunt might increase the qualified success compared to trabeculectomy, but it is not clear whether it has any effect on the rest of the critical outcomes for decision-making because the certainty of the evidence is very low.

Motility Changes and Diplopia After Baerveldt Glaucoma Drainage Device Implantation or After Trabeculectomy

Purpose

The purpose of this study was to quantify any diplopia and motility changes after the implantation of a Baerveldt glaucoma implant (BGI) or after trabeculectomy (TE).

Methods

We analyzed 51 patients with a BGI and 52 patients with a TE from a prospective cohort study. To quantify any diplopia, we asked patients about the presence of diplopia at 1 year after surgery. To quantify any ocular motility changes, we measured ductions in eight gaze directions, the patients' ocular alignment and their fusion range before and 1 year after surgery.

Results

In the BGI group, 14 patients (28%) experienced diplopia compared with one patient (2%) in the TE group (P < 0.001). Duction changes were more commonly observed in the BGI group (35%) than in the TE group (19%). In the BGI group, ductions were mostly restricted in elevation (13%; P < 0.001), in abduction (13%), in elevation in 25° adduction (13%; P = 0.044), and in elevation in 25° abduction (25%; P < 0.001). In 32% of the patients, their near horizontal ocular alignment shifted, notably in exodirection (P = 0.04). The fusion range decreased significantly in the horizontal direction (−12.6° ± 10.3°, mean ± standard deviation; P = 0.01).

Conclusions

BGI surgery was significantly associated with postoperative diplopia and impaired eye motility (reduced ductions), mostly present in abduction, elevation, elevation in 25° adduction, and elevation in 25° abduction. Even without impaired ductions, diplopia could come about.

Translational Relevance

By studying diplopia across glaucoma patients prospectively with diplopia questionnaires and extensive orthoptic measurements, we gain better insight into its occurrence.

Primary Baerveldt versus trabeculectomy study after one-year follow-up

PURPOSE

To compare a Baerveldt implant and trabeculectomy with respect to intraocular pressure (IOP) and failure rate at 1 year of follow-up. Secondary outcomes are pharmacological therapy and complications at 1 year of follow-up.

METHODS

This was a randomized, comparative study. A total of 119 glaucoma patients without previous ocular surgery were included at the Rotterdam Eye Hospital, the Netherlands. One eye of each subject was randomized to either a Baerveldt glaucoma drainage device (BGI) or trabeculectomy (TE). Follow-up visits were conducted at 1 day, 2 weeks, 6 weeks, 3 months, 6 months and 1 year after surgery.

RESULTS

After one year, the final IOP was equivalent for both treatment groups: 14 ± 4 mmHg (mean ± SD) for the Baerveldt group versus 13 ± 4 mmHg for the trabeculectomy group. Statistically, we found no significant difference in failure rate between the two groups. However, the Baerveldt group needed significantly more medication to decrease IOP. Overall, self-limiting complication rate was similar in both groups. Diplopia, a serious complication, was significantly more present in the BGI group.

CONCLUSION

One year after surgery, TE shows better results than the BGI. The final IOP, IOP reduction and failure rate are similar, but the need for additional IOP lowering medication in the BGI group is higher as well as the complication rate. The increased risk of developing diplopia after placement of a BGI must be taken into consideration.

Evaluation of Bleb Fluid After Baerveldt Glaucoma Implantation Using Magnetic Resonance Imaging

We evaluated bleb fluid images taken after Baerveldt glaucoma implantation. T2-weighted images of bleb fluid were scanned with 3 Tesla magnetic resonance imaging in 52 patients who had undergone tube-shunt surgery using the 350-mm² endplate Baerveldt glaucoma implant; three-dimensional images were constructed from these images. Bleb fluid images were classified into either a layer of bleb fluid on either side of the endplate (double bleb layer group; n = 24) or one layer outside the endplate (single bleb layer group; n = 28). Despite there being no correlation between the bleb volume and the postoperative IOP (r = −0.080; P = 0.57), the double bleb layer group had significantly lower postoperative IOPs than the single bleb layer group (12.3 ± 3.8 mmHg vs. 14.7 ± 4.1 mmHg, respectively; P = 0.033). The single bleb layer was significantly related to higher numbers of prior intraocular surgeries (relative risk = 2.85; P = 0.0014). Formation of a layer of bleb fluid on either side of the endplate may have resulted in the lower postoperative IOPs after Baerveldt glaucoma implantation. Repeated intraocular surgery adversely affects formation of the double bleb layer.

Strabismus After Ocular Surgery

Many types of ocular surgery can cause diplopia, including eyelid, conjunctival, cataract, refractive, glaucoma, retinal, and orbital surgery. Mechanisms include direct injury to the extraocular muscles from surgery or anesthesia, scarring of the muscle complex and/or conjunctiva, alteration of the muscle pulley system, mass effects from implants, and muscle displacement. Diplopia can also result from a loss of fusion secondary to long-standing poor vision in one eye or from a decompensation of preexisting strabismus that was not recognized preoperatively. Treatment, which typically begins with prisms and is followed by surgery when necessary, can be challenging. In this review, the incidence, mechanisms, and treatments involved in diplopia after various ocular surgeries are discussed. [J Pediatr Ophthalmol Strabismus. 2017;54(5):272-281.].

Strabismus surgery outcomes in eyes with glaucoma drainage devices

PURPOSE

To report strabismus surgery outcomes in eyes with prior implantation of glaucoma drainage devices (GDD).

METHODS

The medical records of patients who underwent strabismus surgery for ocular misalignment that developed after implantation of a GDD over a 13-year period at a single institution were examined retrospectively. Patient characteristics, deviation types, preoperative measurements, surgical procedures, and postoperative measurements were analyzed.

RESULTS

Of the 16 patients included, 14 had exotropia (34^Δ ± 16^Δ) and 11 had vertical deviations (15^Δ ± 7^Δ), of which 9 had concurrent exotropia and vertical deviations. Preoperatively, 9 patients had diplopia. The surgical approach was tailored to address the deviation most noticeable to the patient-horizontal, vertical, or both if the vertical component could be addressed by horizontal muscle supra- or infraplacement. Three patients underwent simultaneous horizontal and vertical surgery. All patients underwent strabismus surgery on an eye with a GDD. Surgical motor success (defined as horizontal deviation ≤10^Δ, vertical ≤4^Δ) was achieved in 42% of horizontal and 57% of vertical deviations. Postoperatively 74% of deviations decreased by ≥50% in magnitude. Diplopia resolved in 50% of patients who presented with preoperative diplopia. One patient had intraoperative bleb perforation, but none had postoperative hypotony at any follow-up visit. Only 2 required a second strabismus surgery.

CONCLUSIONS

Strabismus surgery with preservation of the filtering bleb following implantation of a glaucoma drainage device is a low risk procedure that can improve ocular alignment and related symptoms, despite a low motor success rate by standard criteria.

Development of a laser controlled device to modulate intraocular pressure

INTRODUCTION

The current standard of treatment for glaucoma is trabeculectomy. The use of glaucoma drainage devices has increased in recent years since its efficacy and safety was established as it provides an alternative surgical option. A downfall of these devices is the lack of proper flow rate control. Areas covered: In this paper we describe a glaucoma drainage device regulator that has already been protoyped and undergone initial testing. It consists of an implantable device with a semipermeable membrane that is used during glaucoma surgery and can be opened with either thermal or photodisruptive laser to adjust the amount of flow precisely and non-invasively, addressing the current difficulties of glaucoma surgeries. A literature search was conducted using MEDLINE and manuscript references for studies published in English between 2000 and 2015 using the terms glaucoma, trabeculectomy and glaucoma drainage devices. Expert commentary: The GDDR device can decrease surgical risk and allow surgeons to post-operatively adjust flow as clinically needed using a non-invasive method. Further testing is planned to substantiate these initial results and evaluate the device's biocompatibility, tunability and efficacy.

Postoperative Complications in the Ahmed Baerveldt Comparison Study During Five Years of Follow-up

PURPOSE

To compare the late complications in the Ahmed Baerveldt Comparison Study during 5 years of follow-up.

DESIGN

Multicenter, prospective randomized clinical trial.

METHODS

setting: Sixteen international clinical centers.

STUDY POPULATION

Two hundred seventy-six subjects aged 18-85 years with previous intraocular surgery or refractory glaucoma with intraocular pressure of >18 mm Hg.

INTERVENTIONS

Ahmed Glaucoma Valve FP7 or Baerveldt Glaucoma Implant BG 101-350.

MAIN OUTCOME MEASURES

Late postoperative complications (beyond 3 months), reoperations for complications, and decreased vision from complications.

RESULTS

Late complications developed in 56 subjects (46.8 ± 4.8 5-year cumulative % ± SE) in the Ahmed Glaucoma Valve group and 67 (56.3 ± 4.7 5-year cumulative % ± SE) in the Baerveldt Glaucoma Implant group (P = .082). The cumulative rates of serious complications were 15.9% and 24.7% in the Ahmed Glaucoma Valve and Baerveldt Glaucoma Implant groups, respectively (P = .034), although this was largely driven by subjects who had tube occlusions in the 2 groups (0.8% in the Ahmed Glaucoma Valve group and 5.7% in the Baerveldt Glaucoma Implant group, P = .037). Both groups had a relatively high incidence of persistent diplopia (12%) and corneal edema (20%), although half of the corneal edema cases were likely due to pre-existing causes other than the aqueous shunt. The incidence of tube erosion was 1% and 3% in the Ahmed Glaucoma Valve and Baerveldt Glaucoma Implant groups, respectively (P = .04).

CONCLUSIONS

Long-term rates of vision-threatening complications and complications resulting in reoperation were higher in the Baerveldt Glaucoma Implant than in the Ahmed Glaucoma Valve group over 5 years of follow-up.

Binocular disturbance after glaucoma drainage device implantation

Binocular vision disturbance is a well-described complication of glaucoma drainage device (GDD) implantation. The pathophysiology is not well-understood, but may involve bulk effects from the implant and surrounding bleb, as well as modulation of muscle function due to surgical trauma and post-operative inflammation, resulting in a combined resection/posterior fixation effect. Retrospective studies have found the risks of motility disorder and diplopia vary widely, estimated to be 56%-86% and 57%-75%, respectively. More recently, cross-sectional studies and prospective trials estimate post-GDD incidence to be approximately 1%-44%, with the incidence in newer generation of implants designed to limit bleb size likely lower at 1%-5%. Suggested methods of management strategies include prismatic spectacles, monocular occlusion, extreme monovision, and strabismus surgery.

Outcomes of glaucoma reoperations in the Tube Versus Trabeculectomy (TVT) Study

PURPOSE

To describe the incidence and outcomes of reoperations for glaucoma in the Tube Versus Trabeculectomy (TVT) Study.

DESIGN

Cohort study of patients in a multicenter randomized clinical trial.

METHODS

The TVT Study enrolled 212 patients with medically uncontrolled glaucoma who had previous cataract and/or glaucoma surgery. Randomization assigned 107 patients to surgery with a tube shunt (350 mm(2) Baerveldt glaucoma implant) and 105 patients to trabeculectomy with mitomycin C (0.4 mg/mL for 4 minutes). Data were analyzed from patients who failed their assigned treatment and had additional glaucoma surgery. Outcome measures included intraocular pressure (IOP), use of glaucoma medications, visual acuity, surgical complications, and failure (IOP >21 mm Hg or not reduced by 20%, IOP ≤5 mm Hg, additional glaucoma surgery, or loss of light perception vision).

RESULTS

Additional glaucoma surgery was performed in 8 patients in the tube group and 18 patients in the trabeculectomy group in the TVT Study, and the 5-year cumulative reoperation rate was 9% in the tube group and 29% in the trabeculectomy group (P = .025). Follow-up (mean ± SD) after additional glaucoma surgery was 28.0 ± 16.0 months in the tube group and 30.5 ± 20.4 months in the trabeculectomy group (P = .76). At 2 years after a glaucoma reoperation, IOP (mean ± SD) was 15.0 ± 5.5 mm Hg in the tube group and 14.4 ± 6.6 mm Hg in the trabeculectomy group (P = .84). The number of glaucoma medications (mean ± SD) after 2 years of follow-up was 1.1 ± 1.3 in the tube group and 1.4 ± 1.4 in the trabeculectomy group (P = .71). The cumulative probability of failure at 1, 2, 3, and 4 years after additional glaucoma surgery was 0%, 43%, 43%, and 43%, respectively, in the tube group, and 0%, 9%, 20%, and 47% in the trabeculectomy group (P = .28). Reoperations to manage complications were required in 1 patient in the tube group and 5 patients in the trabeculectomy group (P = .63).

CONCLUSIONS

The rate of reoperation for glaucoma was higher following trabeculectomy with mitomycin C than tube shunt surgery in the TVT Study. Similar surgical outcomes were observed after additional glaucoma surgery, irrespective of initial randomized treatment in the study.

Diplopia after glaucoma surgery

The occurrence of strabismus and symptomatic diplopia following glaucoma surgery is becoming more common as the use of implanted setons increases. Understanding the factors contributing to the diplopia is critical to the development of treatment strategies to alleviate the patient's symptoms.

Diplopia after glaucoma drainage device implantation

PURPOSE

To determine incidence of diplopia after glaucoma drainage device (GDD) surgery and to report treatment outcomes.

METHODS

Financial claims data were used to identify patients who underwent GDD surgery (CPT [Current Procedural Terminology] 66180) at the Bascom Palmer Eye Institute from January 2, 1991, through December 31, 2005. After a second claims data search, the medical records of patients diagnosed with diplopia (International Classification of Diseases, 9th Revision code 368.2) and those who underwent extraocular muscle surgery (CPT-4 code 67311-67335) after GDD implantation were reviewed retrospectively.

RESULTS

A total of 2,661 patients underwent GDD surgery during the study period. Charges were submitted for 59 patients for strabismus surgery or office visits relating to diplopia. Of these, 27 patients were excluded because medical records did not document diplopia or included pre-existing diplopia, cranial nerve palsy, or diplopia attributed to another ocular procedure. The remaining 32 patients developed diplopia secondary to GDD. Superotemporal quadrant GDDs were identified in 23 eyes and inferonasal quadrant placement in 9 eyes. The 1-year cumulative incidence of diplopia was 1.4%. No patient developed diplopia after 1 year. The mean follow-up after diagnosis for patients with diplopia was 48 ± 27 months (range, 1-124 months). The mean time of onset of diplopia after GDD implantation was 66 ± 62 days, with median onset of 42 days (range, 8-278 days). Treatment of diplopia included prisms in 17 cases (53.1%), no treatment in 13 (40.6%), other therapies in 2 (6.3%), and surgery after prismatic treatment failed in 3 (9.4%).

CONCLUSIONS

The incidence of diplopia after GDD surgery is low, and most patients are treated with prisms.

Combined Baerveldt glaucoma implant and scleral buckling surgery for patients with retinal detachment and coexisting glaucoma

PURPOSE

To report on the usefulness of combined Baerveldt glaucoma implantation (BGI) and scleral buckling surgery for patients with glaucoma requiring a scleral buckle for retinal detachment repair.

METHODS

Retrospective, consecutive, noncomparative, and interventional case series of 30 eyes (30 patients) that underwent simultaneous scleral buckle and BGI surgery, using a staged (group 1, n=21 patients) or nonstaged (group 2, n=9 patients) approach to BGI implantation. Successful intraocular pressure (IOP) control was defined as 6 mm Hg≤IOP≤18 mm Hg.

RESULTS

Although not statistically significant, mean best corrected visual acuity (LogMAR) improved from 2.0 before surgery to 1.7 after surgery (P=0.13) with a mean follow-up of 27.7 months. Of the 21 patients in group 1, only 13 (62%) required second-stage tube insertion at a mean of 7.0±8.0 months (range, 1 to 24 mo) postoperatively. For these eyes combined with group 2 eyes, mean IOP was reduced from 31.1±10.8 to 12.7±6.0 mm Hg (P<0.0001), and the mean number of glaucoma medications was reduced from 2.9±1.4 to 1.2±1.3 (P<0.001). Life table rates of successful IOP control were 90% and 80% at 12 and 24 months, respectively.

CONCLUSIONS

Combined scleral buckle and BGI is an effective technique for managing coexisting glaucoma and retinal detachment and provides the clinician with a useful surgical option while minimizing surgical risk.

Update on aqueous shunts

Medicare claims data and surveys of the American Glaucoma Society membership show that aqueous shunts are being increasingly utilized in the surgical management of glaucoma. New clinical trials data have identified differences in the efficacy and safety of shunts in common use. Recent studies have reported comparable results with trabeculectomy and aqueous shunts in similar patient groups. Intraoperative and postoperative complications may develop with aqueous shunt surgery related to the implantation of a foreign material. Several modifications in surgical technique have been directed toward improving surgical success, reducing complications, and optimizing efficiency and cost.

The Ahmed Baerveldt Comparison Study methodology, baseline patient characteristics, and intraoperative complications

PURPOSE

The Ahmed Baerveldt Comparison (ABC) Study compares the long-term outcomes and complications of the Ahmed glaucoma valve (AGV; model FP7; New World Medical, Los Ranchos, CA) and the Baerveldt glaucoma implant (BGI; model 101-350; Abbott Medical Optics, Abbott Park, IL).

DESIGN

Multicenter, randomized, controlled clinical trial.

PARTICIPANTS

Two hundred seventy-six glaucoma patients at 16 clinical centers worldwide who were 18 to 85 years of age with inadequately controlled intraocular pressure (IOP; ≥18 mmHg) in whom placement of an aqueous shunt was planned.

METHODS

Study patients were randomized to undergo implantation of an AGV or a BGI.

MAIN OUTCOME MEASURES

Failure, defined as IOP >21 mmHg or not reduced by 20% less than baseline or IOP ≤5 mmHg (2 consecutive visits after 3 months), additional glaucoma surgery, removal of the implant, or loss of light perception vision.

RESULTS

A total of 276 patients were enrolled between October 2006 and April 2008, including 143 in the AGV group and 133 in the BGI group. The mean age±standard deviation (SD) of patients enrolled was 63±14 years, and 52% were male. The mean baseline IOP±SD was 31.5±11.8 mmHg. Except for a 13% higher prevalence of hypertension in the AGV group, no significant differences in baseline demographic or ocular characteristics were observed between the study groups. Intraoperative complications occurred in 11 (8%) patients in the AGV group and in 16 (12%) patients in the BGI group (P = 0.31).

CONCLUSIONS

The ABC Study should yield valuable prospective data comparing 2 commonly used aqueous shunts in clinical practice.

Review of results from the Tube Versus Trabeculectomy Study

PURPOSE OF REVIEW

The Tube Versus Trabeculectomy (TVT) Study is a multicenter randomized clinical trial comparing the safety and efficacy of tube-shunt surgery to trabeculectomy with mitomycin (MMC) in eyes with previous cataract and/or unsuccessful glaucoma surgery. This article reviews published results from the TVT Study.

RECENT FINDINGS

Tube-shunt surgery had a higher success rate than trabeculectomy with MMC during the first 3 years of follow-up. Trabeculectomy with MMC produced greater intraocular pressure (IOP) reduction in the early postoperative period compared with tube-shunt placement, but similar IOPs were observed after 3 months. Tube-shunt surgery was associated with greater use of adjunctive-medical therapy than trabeculectomy with MMC during the first 2 years of the study, but no difference in medication use was seen at 3 years. The incidence of postoperative complications was higher after trabeculectomy with MMC compared with tube-shunt surgery, but serious complications associated with vision loss and/or reoperation developed with similar frequency after both surgical procedures. No difference in the rate of vision loss was present following trabeculectomy with MMC and tube-shunt surgery after 3 years of follow-up. Cataract progression was common, but occurred with similar frequency with both procedures.

SUMMARY

Intermediate-term results of the TVT Study support the expanded use of tube shunts beyond refractory glaucomas. Tube-shunt surgery is an appropriate surgical option in patients who have undergone prior cataract and/or unsuccessful filtering surgery.

Results from the tube versus trabeculectomy study

The Tube Versus Trabeculectomy (TVT) Study is a multicenter randomized clinical trial comparing the safety and efficacy of tube shunt surgery to trabeculectomy with mitomycin (MMC) in eyes with previous cataract and/or failed glaucoma surgery. Tube shunt surgery was more likely to maintain intraocular pressure (IOP) control and avoid persistent hypotony, reoperation for glaucoma, or loss of light perception vision than trabeculectomy with MMC during the first year of follow-up. Both surgical procedures had similar IOP reduction at 1 year, but less supplemental medical therapy was used following trabeculectomy. The incidence of postoperative complications was higher after trabeculectomy with MMC relative to tube shunt surgery, but serious complications associated with vision loss and/or reoperation developed with similar frequency after both of the procedures. There was no significant difference in the rate of vision loss following trabeculectomy with MMC and tube shunt surgery after 1 year of follow-up. Cataract progression was common, but occurred with similar frequency with both of the surgical procedures.