Risk factors for exposure of glaucoma drainage devices: a retrospective observational study

Aqueous shunt exposure repair: outcomes and risk factors for recurrence

OBJECTIVE

To investigate the outcomes of aqueous shunt exposure repair and to identify risk factors for recurrent exposure after surgical repair.

METHODS

This is a retrospective interventional case series of consecutive patients who underwent repair of an exposed aqueous shunt. Demographic and clinical data were extracted from the patients' records and survival analysis was employed to determine the probability of survival of the repair without further exposure. Cox proportional regression analysis was utilised to identify potential risk factors for failure of the repair surgery.

RESULTS

Seventy-six eyes of 76 patients were included in the study. The probability of survival without further exposure was 76.2% (CI 66.9-86.8%), 72.7% (CI 62.8-84.1%) and 54.7% (40.5-73.7%) at 1,2 and 4 years, respectively. No eye in which the tube was repositioned in the anterior chamber or in the sulcus (n = 9; 11.8%) developed a recurrence of the exposure. A shorter interval from the time of tube insertion to the repair surgery (HR 2.87 [CI 1.11-7.39]; p = 0.03; reference longer interval), a history of previous surgical revision (HR 3.06 [1.15-8.12]; p = 0.02; reference no prior revision) and the use of a human pericardial donor patch at the time of revision (HR 3.43 [1.16-10.13]; p = 0.03; reference other than pericardium) was associated with an increased risk of exposure recurrence.

CONCLUSION

Aqueous shunt exposure revision is associated with reasonable mid and long term success. A shorter interval from tube insertion to exposure revision, previous revisions and the use of a human pericardium patch were associated with increased risk of failure.

Scleral bridging technique for preventing PreserFlo microshunt exposure: A case report

INTRODUCTION

The use of the PreserFlo microshunt is gaining popularity owing to its ease of implantation and reduced need for postoperative intervention compared to conventional trabeculectomy.

PATIENT CONCERNS

However, microshunt exposure remains a severe complication of PreserFlo surgery, particularly in patients with a thin Tenon capsule and conjunctiva. However, the actual thickness and intensity of the Tenon capsule or conjunctiva can be confirmed only during surgery.

DIAGNOSIS

Exfoliation glaucoma with previous several glaucoma surgeries with thinner Tenon capsule or conjunctiva.

INTERVENTIONS

We performed PreserFlo implantation with a surgical technique to recover a thin Tenon capsule and conjunctiva by creating a half-thickness rectangular scleral flap under the shunt and covering it over the microshunt until the distal part, similar to the bridge.

OUTCOMES

The patient had better intraocular pressure control with positive cosmetic appearance using this technique.

CONCLUSION

This technique will be beneficial for both preventing exposure and holding down the top, in addition to improving cosmetic appearance.

Evaluation of pericardium patch graft thickness in patients with Ahmed glaucoma valve implantation: an anterior segment OCT study

PURPOSE

To evaluate the changes in thickness of tissues, specifically the pericardium patch graft (PPG) covering the silicone tube in Ahmed Glaucoma Valve (AGV) surgery.

STUDY DESIGN

Prospective observational study.

METHODS

This study included cases with refractory glaucoma that underwent AGV implantation with PPG coverage. Conjunctival epithelium, stroma and PPG thickness covering the tube were measured using anterior segment optical coherence tomography (AS-OCT) at 1, 6 and 12 months. Additionally, the same measurements were taken 1500 µm away from the tube as a control for the central measurements.

RESULTS

Twenty-seven eyes of 27 patients were evaluated in the study. Although PPG thickness decreased significantly in both regions, the amount of reduction was more pronounced centrally. Centrally, the reduction rate was 21.2% and 34.8% during the 1-6 months period and 6-12 months period, while peripherally it was 3.5% and 5.1%, respectively. No change was observed in the thickness of the epithelium during the follow-up period. There was a significant thinning of the stroma in the central and peripheral regions during the 1-6 months period (30.5% and 17%, respectively). No cases of exposure were observed during the follow-up period.

CONCLUSION

Although the most evident thinning of the layers covering the tube was observed in the early postoperative period, PPG showed a stable decrease even in the late period. The progressive reduction in the PPG thickness observed also in the peripheral region indicates that factors beyond mechanical forces contribute to this degenerative process. AS-OCT could be a valuable non-invasive tool in clarifying this process.

Five-Year Outcomes of Graft-Free Tube Shunts and Risk Factors for Tube Exposures in Glaucoma

PRCIS

Use of a scleral tunnel technique instead of a patch graft can be considered in most cases of tube shunt implantation. Grafts may still be considered in younger (<65 y old) East Asians.

PURPOSE

(1) To assess the risk factors for tube exposure with a graft-free implantation technique and (2) to examine 5-year outcomes of graft-free tube shunt insertion.

METHODS

This was a retrospective case series of 204 consecutive eyes undergoing a glaucoma tube shunt implantation with a scleral tunnel technique in lieu of a graft. Preoperative and postoperative best-corrected visual acuity, intraocular pressure, and number of glaucoma medications were compared. Failure was defined as the following: (1) intraocular pressure >21 mm Hg or ≤5 mm Hg on 2 consecutive visits after 3 mo; (2) required additional glaucoma surgery; (3) loss of light perception. Univariable and multivariable regression analyses were conducted to identify risk factors of tube exposures.

RESULTS

Intraocular pressure and the number of glaucoma medications were significantly decreased at all postoperative time points ( P <0.001). Success rates were 91% at year 1, 75% at year 3, and 67% at year 5. The most common early (<3 mo) complication was tube malpositioning. The most common late (>3 mo to 5 y) complications were corneal complications and uncontrolled intraocular pressure. By year 5, 6.9% of tubes were exposed. Multivariable regression showed that age less than 65 years old (odds ratio: 3.66, P =0.04) and East Asian ethnicity (odds ratio: 3.36, P =0.04) were associated with significantly increased risk of tube exposure.

CONCLUSIONS

Graft-free glaucoma tube implantation has comparable long-term outcomes and complication rates to shunts with a graft. Younger (<65 y old) East Asians are at greater risk of tube exposure without a graft.

Scleral Grafts in Ophthalmic Surgery. A Review

AIM

To summarize the history and current trends in the use of scleral grafts in ophthalmology.

MATERIALS AND METHODS

We conducted a review of the literature through the MEDLINE and Cochrane Library databases. The search terms were "sclera", "graft", and "surgery". The search resulted in 1596 articles, of which we evaluated 192 as relevant. The relevant articles were sorted chronologically and according to the method of using scleral grafts, which enabled the development of a review article.

RESULTS

The sclera has been routinely used in ophthalmology since the 1950s in many different indications. Some of these indications have become practically obsolete over time (for example, use in the surgical management of retinal detachment), but a large number still find application today (especially use in glaucoma or oculoplastic surgery, or as a patch for a defect in the sclera or cornea).

CONCLUSION

Even though allogeneic sclera is currently used less frequently in ophthalmology compared to other tissue banking products and the range of its indications has partially narrowed, it remains a useful material due to its availability and properties.

Modified Split-Thickness Corneal Patch Graft for Conjunctival Erosions in Patients With the Port Delivery System Implant: Surgical Technique and Long-Term Outcomes

Purpose: To describe the surgical technique and long-term outcomes of a modified split-thickness corneal patch grafting for conjunctival erosions that can be seen in patients with the Port Delivery System (PDS) implant. Methods: By way of retrospective review of medical records, this interventional case series identified 2 cases in which modified split-thickness corneal patch grafting was used to repair conjunctival erosion in patients with the PDS implant. Results: The surgical approach involved creating a small opening in the corneal graft over the center of the PDS implant to improve visibility and allow for easier access during subsequent refill-exchange procedures. At the last follow-up of 6.9 years and 5.6 years, there was no recurrence of conjunctival erosions in either patient. The PDS implants remained well covered with the split-thickness corneal graft and had undergone multiple implant refills without complication or difficulty. Conclusions: Modified split-thickness corneal patch grafting with central graft aperture offers another option for long-term successful management of conjunctival erosions in patients with a PDS, especially those who have failed prior repair, by allowing sufficient visibility and access for subsequent refill-exchange procedures.

The Success Rate of Glaucoma Drainage Device Revision

PRCIS

We report the survival of surgical revision to glaucoma drainage devices for several indications in a large cohort of patients, with an overall success rate of 45% at 36 months.

PURPOSE

To evaluate the outcomes of surgical revision for complications of glaucoma drainage devices.

METHODS

Three hundred thirty-five eyes of 318 patients who underwent tube revision or removal at University of California Los Angeles (UCLA) Jules Stein Eye Institute between 1997 and 2019 were included. The pre-defined primary outcome measure was surgical success of the initial revision, defined as resolution of the condition with no additional revisions required, no functionally significant change in vision, and no instances of intraocular pressure > 21 mmHg at 2 consecutive visits postoperatively. Kaplan-Meier survival analysis was applied to evaluate survival at 36 months based on these criteria. The Wilcoxon paired test was used to compare mean preoperative and postoperative intraocular pressure, medication usage, and visual acuity.

RESULTS

Overall, survival of revised tubes at 36 months was 45%. The 4 most common indications for revision were exposure of the implant (42% of all revisions), occlusion (14%), corneal failure or threat of failure (12%), and hypotony (11%). Survival at 36 months for each of these indications was 44%, 45%, 52%, and 37%, respectively.

CONCLUSIONS

These results suggest that eyes with glaucomatous damage with long-term glaucoma drainage device complications can still have a reasonably successful outcome when a revision is performed. However, with substantial rates of vision loss and a frequent need for additional revisions to manage complications, managing patient expectations for success and making them aware of the likelihood of additional surgeries or failure is important.

Risk Factors for Glaucoma Drainage Device Exposure in Children: A Case-Control Study

PURPOSE

To identify the risk factors for glaucoma drainage device (GDD) exposure in children.

DESIGN

Retrospective case-control study.

METHODS

The study population comprised children (one eye each) who presented with a history of GDD exposure to a tertiary care eye hospital over the period January 2014 to January 2020. Consecutive children (age <18 years) were included. A control group from the same time period (children without GDD exposure) were included in the ratio of 5 controls to every 1 case of exposure. The main outcome measures included risk factors for exposure (univariate and multivariate analysis).

RESULTS

A total of 21 eyes (of 21 children with implant exposure) and 115 eyes (of 115 children without exposure) were included in this study. During the same study period, a total of 494 eyes had undergone GDD implantation, giving an estimated incidence of exposure of 4.25%). In the bivariate analysis, GDD exposure was associated with multiple previous ocular surgeries (P = .001), longer follow-up duration (P < .001), combined procedure at the time of primary implantation (P = .002), and a younger age at the time of primary implantation (P = .006). The former 3 risk factors continued to prove a statistically significant association on multivariable regression analysis. Postoperative use of eye lubricants was more common among children in the control group (P = .007).

CONCLUSION

In pediatric glaucoma patients, younger age and combined procedure at the time of primary GDD implantation, in addition to multiple previous ocular surgeries, were associated with greater risk of implant exposure. Postoperative use of eye lubricants may be protective.

Risk Factors for Glaucoma Drainage Device Revision or Removal Using the IRIS Registry

PURPOSE

To elucidate risk factors for revision or removal of glaucoma drainage devices (GDD) in glaucoma patients in the United States.

DESIGN

Retrospective cohort study.

METHODS

IRIS Registry (Intelligent Research in Sight) patients who underwent GDD insertion between January 1, 2013 and December 31, 2018 were included. Various demographic and clinical factors were collected. Kaplan-Meier survival plots, Cox proportional-hazard models utilizing Firth's Penalized Likelihood, and multivariate linear regression models were used. The main outcome measures were hazard ratios (HR) and beta coefficient (β) estimates.

RESULTS

A total of 44,330 distinct patients underwent at least 1 GDD implantation, and 3354 of these underwent subsequent GDD revision or removal surgery. With failure defined as GDD revision/removal, factors significantly associated with decreased failure included unknown race (HR = 0.83; P = .004) and unknown ethnicity (HR = 0.68; P < .001). Factors associated with increased risk of GDD revision/removal surgery included presence of chronic angle-closure glaucoma (HR = 1.32; P < .001) and dry eye disease (HR = 1.30; P = .007). Additionally, factors associated with a decreased average time (in days) to GDD revision/removal included male sex (β = -25.96; P = .044), unknown race (β = -55.28; P = .013), and right-eye laterality (β = -38.67; P = .026). Factors associated with an increased average time to GDD revision/removal included having a history of a past eye procedure (β = 104.83; P < .001) and being an active smoker (β = 38.15; P = .024).

CONCLUSIONS

The size and scope of the IRIS Registry allows for detection of subtle associations between risk factors and GDD revision or removal surgery. The aforementioned demographic and clinical factors may all have an impact on GDD longevity and can inform the treatment options available for glaucoma patients.

Management Patterns and Visual Outcomes of Endophthalmitis After Glaucoma Drainage Device Placement: A Case Series

PURPOSE

To describe clinical presentation, management, and outcomes of eyes with endophthalmitis related to glaucoma drainage device (GDD) placement.

PATIENTS AND METHODS

Retrospective chart review of patients diagnosed with GDD-related endophthalmitis at Duke Eye Center from 2009 to 2018.

RESULTS

Six eyes of 6 patients had endophthalmitis related to a GDD (2 Ahmed, 4 Baerveldt). The mean time from surgery to presentation was 22.7 months. Five of 6 cases (83%) had culture-proven infectious endophthalmitis. Eyes undergoing GDD explantation (n=2) had better visual acuity at 6 months compared with those without hardware removal (20/11,314 vs. 20/358). Visual acuity at 6 months was hand motion (20/8000) or worse in 3 of 6 cases (50%).

CONCLUSIONS

GDD-related endophthalmitis often leads to poor visual outcomes. Hardware removal may lead to improved visual outcomes; a multicenter prospective study assessing the benefit of hardware removal may be warranted.

The best thickness of cornea graft from SMILE surgery as patch graft in glaucoma drainage implant surgery

OBJECTIVE

The aim of this study was to determine the best thickness of corneal slices acquired from femtosecond laser surgery-small incision lenticule extraction (SMILE surgery) as patch graft in glaucoma drainage implantation surgery.

METHODS

This study is a prospective randomized study. Patients who received glaucoma drainage implantation from September 2016 to November 2018 were observed. The patients were randomly divided into 3 groups. Group A included 102 cases (104 eyes), receiving 1 layer (120-150 μm) of allogeneic lamellar corneal tissue as the graft. Group B included 117 cases (120 eyes), receiving 2 layers of lamellar corneal tissue from one donor. Group C included 109 cases (111 eyes), using 3 layers of lamellar corneal tissue from 2 donors. The intraocular pressure, corneal graft, conjunctiva stromalysis, drainage tube exposure, and drainage plate were observed.

RESULTS

Patients were followed up for 6 to 33 months. The intraocular pressure was significantly reduced after surgery in all three groups. Conjunctiva stromalysis and drainage tubes were exposed in 3 eyes (3%) in group A and 1 eye (0.8%, a special case which has nystagmus and the plate was placed infratemporally) in group B, whereas no conjunctiva stromalysis or tube exposure was reported in group C.

CONCLUSIONS

The corneal graft acquired from SMILE surgery can effectively prevent drainage tube exposure and give patients a better cosmetic appearance. Two layers of lamellar corneal tissue (240-300 μm) may be the best suitable thickness because it can effectively reduce tube exposure and rejection. In some special cases, 3 layers of lamellar corneal tissue are needed.

Glycerin-preserved Human-donor Corneoscleral Patch Grafts for Glaucoma Drainage Devices

PRECIS

Glycerin-preserved, human-donor, corneoscleral patch grafts are effective and safe for glaucoma drainage device (GDD) implantation, and they are comparable to previously reported materials. It can be preserved with the sterile technique for up to 12 months.

PURPOSE

To evaluate the efficacy and safety of glycerin-preserved human donor corneoscleral tissue as the patch graft for GDD implantation.

PATIENTS AND METHODS

This was a retrospective noncomparative study from the medical records of 102 eyes from 102 glaucoma patients who underwent GDD implantation by or under supervision of a single surgeon (N.K.) at the Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand between January 2006 and December 2016. The glycerin-preserved human-donor corneoscleral tissue was used as the patch graft to cover the tube portion of GDD over the sclera. The primary outcome measure was the occurrence of patch graft-related complications.

RESULTS

There were 64 males and 38 females with the mean age of 52.8±18.5 years. The underlying diseases included failed filtration surgery with primary open-angle glaucoma 32 eyes and primary angle-closure glaucoma 15 eyes, congenital glaucoma 3 eyes and secondary glaucoma 52 eyes. The mean of ocular surgeries before GDD implantation was 2.3±1.1. Patch graft-related complications included tube exposure in 4 eyes (3.9%) and wound leakage in 4 eyes (3.9%). Eyes with tube exposure underwent regrafting 3 eyes and tube reposition 1 eye. Eyes with wound leaking resolved spontaneously 2 eyes and underwent conjunctival resuturing 2 eyes. The 5-year survival rate of the corneoscleral graft was 95.7%. There was no recurrence of graft-related complications after surgical procedure to correct the complications. Postoperatively, the mean of intraocular pressure and antiglaucoma medications decreased significantly from 27.4±9.8 mm Hg and 3.8±0.93 to 13.8±6.4 mm Hg (P<0.001) and 1.6±1.5 (P<0.001) at the last visit, respectively. The mean follow-up time was 59.9 months (range, 1 to 144.7 mo).

CONCLUSION

The glycerin-preserved human-donor corneoscleral tissue using as the patch graft was a safe alternative for GDD tube coverage. The patch graft-related complications was comparable to other materials.

Assessing patient cosmetic satisfaction after glaucoma drainage device surgery for different patch grafts

BACKGROUND

The use of a tissue patch graft is common practice with a glaucoma drainage device (GDD). Patch grafts can be visible in the palpebral fissure and may be cosmetically displeasing for some patients. The aim of this study was to report the cosmetic satisfaction of pericardial, scleral, and corneal patch grafts related to superior GDD surgery.

METHODS

Baseline clinical data were collected for consecutive patients with glaucoma operated between 2014 and 2019 at two tertiary eye care institutions (for superiorly-placed) Ahmad glaucoma valve implant using sclera, cornea and pericardium patch graft. A patient questionnaire that contained 4 concise questions, with a Likert-scale grading relating to cosmetic satisfaction was administered by a telephone-based interview. Responses and scores for each question were compared across patients who received the three different types of graft. A binominal logistic regression analysis was used to assess the effects of age, gender, type of graft, number of previous ocular surgeries, and final visual acuity to explain differences.

RESULTS

We included 92 patients who met our inclusion criteria (24 patients received a corneal patch graft, 30 who received sclera and 38 who received pericardium). The mean (±SD) age was 50 (±17.5) years, and the average follow up was 20.7 (± 18.6) months. Regardless of the type of patch graft, most (67-84%) of patients were satisfied with the appearance of their eyes. Patients who received cornea or sclera were more likely to report that their eye looked 'abnormal' by others. Younger age was significantly associated with the response to this question.

CONCLUSION

Patients are generally satisfied with the appearance of their eye following GDD surgery with each of the patch grafts for superiorly-placed GDDs. Younger patients with cornea or sclera were more likely to report that their eyes looked abnormal.

Comparison of Locally Sourced Pericardium and Other Conventional Patch Graft Materials in a Glaucoma Drainage Device Surgery

Purpose

Our study aimed to compare the outcomes and costs of various patch graft materials used in the setting of glaucoma drainage device (GDD) surgeries: conventional Tutoplast® pericardium (TP), locally-obtained Lifenet® pericardium (LP), and tissue-banked corneal (CP) and scleral (SP) patches.

Design

Retrospective observational study.

Subjects

One hundred and ninety-five eyes of 185 patients who underwent glaucoma device surgery with patch grafts were included.

Materials and methods

Patient records were reviewed for demographics and surgical data including age at the time of GDD surgery, race, sex, eye, history of diabetes or immunologic disease, glaucoma diagnosis, length of follow-up, pre- and postoperative intraocular pressure (IOP), type and location of GDD, patch type, and tube-related complications.

Main outcome measures

The primary outcome measures were rates of patch graft-related complications including conjunctival dehiscence with and without tube exposure. Secondary outcome measures were IOP control achieved and cost of patch graft materials.

Results

Mean follow-up for all eyes was 17.1 months. Overall, conjunctival dehiscence without tube exposure occurred in four eyes (2.1%); tube exposure was seen in six eyes (3.1%). The mean time to exposure was 3.3 months (range 1–8 months). The rate of tube exposure was 2.3% of eyes with TP grafts, 10.7% of eyes with CP grafts, 2.8% of eyes with SP grafts, and 0% of eyes with LP grafts. There was no significant difference in rates of tube exposure rates by graft material (p = 0.26). Multivariate logistic regression analysis with adjustment for patch type, age, sex, implant type, and location revealed no significant risk factors for tube exposure. Univariate logistic regression was then performed on the same risk factors as well as diabetes, prior and concurrent ocular surgery, and showed no significance.

Conclusion

Our preliminary, short-term results show that locally sourced patch graft material can be a cost-effective alternative to traditionally used patch grafts without an increase in tube exposure rates. To further determine the efficacy of the different patch graft materials, longer-term comparative prospective trials are needed. Longer prospective studies are needed to compare the long-term safety and rate of tube exposures in these locally obtained patch graft materials.

How to cite this article

Aggarwal S, Kremer C, Engelhard S, et al. Comparison of Locally Sourced Pericardium and Other Conventional Patch Graft Materials in a Glaucoma Drainage Device Surgery. J Curr Glaucoma Pract 2021;15(1):14–18.

Tube Revision Outcomes for Exposure with Different Repair Techniques

Purpose

The aim of this study was to report our experience with eyes that presented with an initial GDD exposure and their subsequent outcome in terms of re-exposure.

Methods

A retrospective review of charts of 42 patients (43 eyes) who presented with a GDD exposure during the period 2008–2015 in a tertiary eye care center was performed. Demographic data, past ocular history, pre-operative and post-operative information including the surgical technique of GDD surgery and exposure repair were recorded. The patients were followed for further exposure to the date of the last follow-up clinic visit. For each type of repair technique, details were collected on risk and timing of GDD exposure. The baseline features of eyes that had further exposure after initial exposure were compared to eyes without further exposure.

Results

Forty-three eyes were identified which had repair after an initial exposure. The mean ± SD age was 54 ± 27 years. Of the GDDs, Ahmed FP7 was performed in 31 eyes, Ahmed FP8 in two eyes, Ahmed S2 in five eyes, Krupin valve in two eyes and Baerveldt 350 GDD in three eyes. The methods of repair and the relative risk [95% CI] of re-exposure were: conjunctival closure only (n=4; RR=2.10 [0.84–5.23]); repair with patch graft and conjunctival repair (n=18), RR=1.24 [0.51–3.01]; tube repositioning, use of patch graft and conjunctival repair (n=14), RR=1.0; tube removal with replacement in a different quadrant, patch graft and conjunctival repair (n=3), RR=1.87 [0.64–5.48]. After the first exposure, 18 eyes had a second re-exposure, four eyes had a third re-exposure, and 1 eye had a fourth exposure.

Conclusions

The GDD exposure rates at our institution are consistent with other reports. Lack of a patch graft for repair is associated with a two-fold risk of subsequent re-exposure.

Recurrent Tube Erosions with Anti-Vascular Endothelial Growth Factor Therapy in Patients with Age-Related Macular Degeneration

PURPOSE

To determine the rates of primary and recurrent glaucoma tube shunt erosions in patients with age-related macular degeneration (AMD) receiving anti-vascular endothelial growth factor (VEGF) intravitreal injections.

DESIGN

Retrospective case series.

PARTICIPANTS

Patients with AMD who underwent tube revision for erosion at the Duke Eye Center from January 1, 1999, to January 1, 2019, were identified. Patients with and without anti-VEGF injections were compared.

METHODS

Patient demographics, ocular diagnoses, glaucoma tube shunt types and locations, and dates of glaucoma surgeries and anti-VEGF injections were collected. Statistical analyses were performed with P < 0.05 as significant.

MAIN OUTCOME MEASURES

Outcome measures included the number of tube erosions, time from anti-VEGF injection to tube erosion, and secondary complications after tube revisions.

RESULTS

A total of 150 patients with AMD with anti-VEGF (309 tubes) and 262 patients with AMD without anti-VEGF (459 tubes) were identified. There was no statistically significant difference in the number of tube erosions in patients with anti-VEGF (15 tubes, 4.8%) versus without anti-VEGF (12 tubes, 2.6%) (P = 0.10). However, patients receiving anti-VEGF had on average a greater number of tube erosion events (2.1±0.7 events) compared with patients without anti-VEGF (1.3±0.7, P < 0.01). Ten patients (91%) received concurrent anti-VEGF injections at the time of tube erosion, and the average duration of prior anti-VEGF therapy was approximately 2 years. Tube erosion was noted 46.5±60.7 days from the preceding anti-VEGF injection. Secondary complications after tube revision in the anti-VEGF group included 5 explanted tubes for recurrent erosions.

CONCLUSIONS

Our results suggest intravitreal anti-VEGF injections are linked to higher rates of recurrent glaucoma tube erosions in patients with AMD. The majority of patients received chronic and serial anti-VEGF injections. Thus, additional consideration should be given to glaucoma surgical planning in patients receiving anti-VEGF injections, especially in those with a primary tube erosion.

Risk factors for exposure of Baerveldt glaucoma drainage implants: a case-control study

Background

Glaucoma drainage implant exposure is one of the serious complications after glaucoma drainage implant surgery. The purpose of this study is to evaluate the risk factors for exposure of the device after implantation of a Baerveldt glaucoma drainage implant.

Methods

This is a retrospective review of the medical records of all patients who underwent Baerveldt glaucoma drainage implant surgery at the Hiroshima University Hospital between April 1, 2012 and October 31, 2016, and who were followed for at least 6 months after surgery. We examined the risk factors for implant exposure based on data obtained from the medical records, with a particular focus on the differences in implant models.

Results

A total of 80 eyes from 80 patients were identified; all patients were Japanese. In this study, the rate of Baerveldt glaucoma drainage implant exposure was 15.0% (12 of 80 eyes). The exposure rate for the BG 102-350 tended to be higher than that for the BG 101-350 and BG 103-250 (p = 0.092; adjusted odds ratio = 3.34; 95% confidence interval, 0.82–13.58). In the patients who had diabetic mellitus, the BG 102-350 showed a significant risk of implant exposure (p = 0.038; adjusted odds ratio = 15.36; 95% confidence interval, 1.17–202.59).

Conclusions

In Baerveldt glaucoma drainage implant surgery in patients with diabetes, using the BG 102-350 was associated with greater risk of implant exposure compared with using the BG 101-350 or BG 103-250.

The results of Baerveldt glaucoma implant surgery performed with the scleral flap and patch technique

BACKGROUND

We report the results of Baerveldt glaucoma implant (BGI) surgery performed with the scleral flap and patch technique.

PATIENTS AND METHODS

This was a retrospective analysis of 97 consecutive patients (107 eyes) who underwent BGI surgery with the scleral flap and patch, and were followed up for >1 year. We evaluated the patients' post-operative intraocular pressure (IOP), corneal endothelial cell density, and complications (corneal edema, Hoffmann elbow exposure).

RESULTS

The preoperative IOP was 32.9 ± 8.6 mmHg. BGI surgery significantly decreased the IOP to 11.1 ± 3.8, 11.3 ± 3.6, 11.3 ± 4.2, 10.7 ± 3.8, and 11.4 ± 3.2 mmHg at 1, 2, 3, 4, and 5 years post-surgery (p < 0.001), respectively. The success rates at 1, 2, 3, 4, and 5 years were 96.3%, 94.8%, 94.8%, 88.5%, and 88.5%, respectively. Failure occurred in six eyes. The reasons for failure were as follows: a postoperative IOP ⩾21 mmHg in one patient, and loss of light sensation in five patients. No patients required additional glaucoma surgery. There were no cases of Hoffmann elbow erosion. Corneal edema occurred in five patients.

CONCLUSION

BGI surgery performed with the scleral flap and patch significantly decreased the IOP, and no case of Hoffmann elbow erosion was observed over the 5-year post-operative period.

Risk Factors for Glaucoma Drainage Device Exposure in a Middle-Eastern Population

PRéCIS:: In this case-control study, female sex, and older age were risk factors for tube exposure; risk was related to the number of prior ocular surgeries and scleral patch graft (compared with pericardial graft) was found to protect against exposure.

PURPOSE

Identification of potential risk factors for glaucoma drainage device (GDD) exposure may help to prevent this potentially blinding complication. The purpose of this study was to evaluate the possible risk factors for GDD exposure in a tertiary eye care center in the Middle-East.

METHODS

A retrospective case-control study was undertaken for a 7-year period (2008 to 2015 inclusive). All patients who presented with a GDD incident exposure were identified and were compared with a similar number of controls (without exposure) identified during the same period. Demographic factors, past ocular history, treatment, and surgical technique were recorded for both groups. Bivariate and multivariable analyses were used to identify possible risk factors for tube exposure.

RESULTS

A total of 836 patients underwent GDD surgery during this time period and 53 patients were identified with exposure, giving a cumulative incident exposure rate of 6.3% (0.9% per year). Bivariate analysis showed that the median age of cases (51 years) was similar to controls (53 years) (P=0.95), while there was a greater proportion of women with exposure (49%) compared with the control group (28%) with a statistically significant difference (P=0.028). The number of previous surgeries (3.77±2.1) was significantly higher (P=0.018) in the exposure group (4.25±2.0) compared with controls (3.3±2.0). With each unit increase in the number of previous surgeries, the odds of exposure significantly increased by 1.29 (95% confidence interval, 1.05-1.57). In the multivariable regression, female sex (P=0.006) and older age (P=0.025) were significant risk factors and use of a scleral patch (P=0.02) graft potentially protective.

CONCLUSIONS

Previous surgery, female sex, and older age are potential risk factors identified in our study. The use of scleral patch graft is potentially protective against GDD extrusion. Further study is needed to elucidate the reasons for these causative and protective factors.

Factors Associated with Conjunctival Erosions after Ahmed Glaucoma Valve Implantation

PURPOSE

To investigate the frequency of conjunctival erosions in a series of patients who underwent Ahmed valve implantation in a tertiary referral center and to study risk factors associated with the conjunctival erosions.

METHODS

This is a single-center, retrospective case-control study of all patients who underwent Ahmed valve implantation between October 2006 and July 2016 at the Kresge Eye Institute in Detroit, Michigan. The series consisted of 306 eyes (277 patients) that underwent Ahmed valve implantation. The rate of conjunctival erosions was determined. Univariate, bivariate, and Cox-proportional hazard analyses were performed to identify factors associated with conjunctival erosions.

RESULTS

During the study period, 23 erosions occurred in 306 eyes (7.52%). Aphakia was significantly more common in eyes with erosions (P < 0.05). Aphakia (P = 0.02), uveitic glaucoma (P = 0.03), and longer post-operative use of topical steroids (P < 0.04) significantly increased the risk of erosions based on the Cox model. There were similar rates of erosions with each type of patch graft. No conjunctival erosion was observed after using the modified scleral tunnel method (n = 10).

CONCLUSIONS

The overall erosion rate was 7.52% in our series. Uveitic glaucoma, aphakia, and longer post-operative use of topical steroids were significantly associated with conjunctival erosions.

Graft Survival after Penetrating Keratoplasty in Cases of Trabeculectomy versus Ahmed Valve Implant

Purpose

To compare the corneal graft survival rates after penetrating keratoplasty (PKP) in cases of post-PKP glaucoma managed by either trabeculectomy with mitomycin C or Ahmed glaucoma valve (AGV).

Methods

This study was a retrospective interventional comparative study that included 40 eyes of 40 patients. The included patients had undergone previous PKP for anterior segment reconstruction after microbial or fungal keratitis, chemical burns, trauma, or perforated corneal ulcer. Post-PKP glaucoma was managed surgically by either trabeculectomy with mitomycin C (group 1) or Ahmed glaucoma valve (group 2).

Results

The first group (n=20) had undergone trabeculectomy with MMC, and the second group (n=20) had undergone AGV implantation. Regarding BCVA, there was no statistically significant difference between the 2 groups. Mean IOP was significantly lower in the AGV group at 6 months, 12 months, and 24 months (p=0.001). Mean IOP at 24 months dropped significantly from preglaucoma surgery levels in both groups (p=0.001). Rejection episodes occurred in 2 eyes (10%) of the trabeculectomy group versus 8 eyes (40%) in the AGV group (p=0.028). In the trabeculectomy group, corneal graft failure occurred in 1 (5%), 3 (15%), and 6 (30%) eyes at 6 months, 12 months, and 24 months, respectively. In the AGV group, corneal graft failure occurred in 2 (10%), 5 (25%), and 10 (50%) eyes at 6 months, 12 months, and 24 months, respectively. The mean time to failure in the trabeculectomy group was 12.33 ± 5.60 months versus 11.90 ± 5.70 months in the AGV group (p=0.027).

Conclusion

Managing postpenetrating keratoplasty glaucoma could be bothersome especially in complex cases. Ahmed glaucoma valve implant controls the intraocular pressure more effectively than trabeculectomy with mitomycin C. However, Ahmed glaucoma valve can result in higher rates of corneal graft failure in a shorter duration of time. This trial is registered with PACTR201712002861391 on 21 Dec 2017.

Graft Survival after Penetrating Keratoplasty in Cases of Trabeculectomy versus Ahmed Valve Implant

Purpose

To compare the corneal graft survival rates after penetrating keratoplasty (PKP) in cases of post-PKP glaucoma managed by either trabeculectomy with mitomycin C or Ahmed glaucoma valve (AGV).

Methods

This study was a retrospective interventional comparative study that included 40 eyes of 40 patients. The included patients had undergone previous PKP for anterior segment reconstruction after microbial or fungal keratitis, chemical burns, trauma, or perforated corneal ulcer. Post-PKP glaucoma was managed surgically by either trabeculectomy with mitomycin C (group 1) or Ahmed glaucoma valve (group 2).

Results

The first group (n=20) had undergone trabeculectomy with MMC, and the second group (n=20) had undergone AGV implantation. Regarding BCVA, there was no statistically significant difference between the 2 groups. Mean IOP was significantly lower in the AGV group at 6 months, 12 months, and 24 months (p=0.001). Mean IOP at 24 months dropped significantly from preglaucoma surgery levels in both groups (p=0.001). Rejection episodes occurred in 2 eyes (10%) of the trabeculectomy group versus 8 eyes (40%) in the AGV group (p=0.028). In the trabeculectomy group, corneal graft failure occurred in 1 (5%), 3 (15%), and 6 (30%) eyes at 6 months, 12 months, and 24 months, respectively. In the AGV group, corneal graft failure occurred in 2 (10%), 5 (25%), and 10 (50%) eyes at 6 months, 12 months, and 24 months, respectively. The mean time to failure in the trabeculectomy group was 12.33 ± 5.60 months versus 11.90 ± 5.70 months in the AGV group (p=0.027).

Conclusion

Managing postpenetrating keratoplasty glaucoma could be bothersome especially in complex cases. Ahmed glaucoma valve implant controls the intraocular pressure more effectively than trabeculectomy with mitomycin C. However, Ahmed glaucoma valve can result in higher rates of corneal graft failure in a shorter duration of time. This trial is registered with PACTR201712002861391 on 21 Dec 2017.

Risk Factors for Earlier Reexposure of Glaucoma Drainage Devices

PURPOSE

The purpose of this study was to investigate factors associated with a second exposure of a glaucoma drainage device (GDD) following repair of an initial GDD exposure.

MATERIALS AND METHODS

This IRB-approved retrospective cohort study examined the incidence of a second exposure of a GDD following initial repair for exposure. Logistic regression was performed to assess the relationship between demographic and clinical characteristics and a second exposure of the GDD. Kaplan-Meier survival curves were plotted and Cox regression was performed to examine factors impacting the time to a second GDD exposure.

RESULTS

Ninety-four eyes of subjects that underwent initial revision for GDD exposure were reviewed. Approximately 44% (N=41/94) of subjects underwent surgical revision for a second exposure. Factors associated with reexposure in multivariate logistic regression included caucasian race (odds ratio, 2.99; P=0.02) and use of a nonscleral patch graft (odds ratio, 2.93; P=0.019). Time from revision of the initial exposure to reexposure was significantly shorter for those with a nonscleral patch graft (hazard ratio, 2.23; P=0.01) and caucasian race (hazard ratio, 2.08; P=0.04).

CONCLUSIONS

Caucasian race and use of a nonscleral patch graft during revision surgery was associated with a higher risk of experiencing a sooner reexposure of the GDD following revision of an initial exposure. Future studies should examine whether particular graft materials increase the risk of GDD reexposure.

Heterologous, Fresh, Human Donor Sclera as Patch Graft Material in Glaucoma Drainage Device Surgery

PURPOSE

To determine the safety and efficacy of fresh, human sclera allografts as a patch graft material in glaucoma drainage device (GDD) surgery.

DESIGN

Retrospective, noncomparative, interventional, consecutive case series.

SUBJECTS

All GDD cases operated between 2008 and 2013 in which fresh human corneoscleral rims were used immediately after the central corneal button was used for penetrating or endothelial keratoplasty.

METHODS

Surgery was performed by 2 surgeons at 2 facilities. The Ahmed Glaucoma Valve (FP-7) was used exclusively in this cohort. Sixty-four eyes of 60 patients were identified; demographic data were recorded along with intraocular pressure (IOP), medication requirements, visual acuity, complications, and subsequent interventions.

MAIN OUTCOME MEASURES

Incidence of complications. IOP and medication requirements at the last follow-up. Quilified success utilizing Tube Versus Trabeculectomy study criteria.

RESULTS

The mean age of the cohort was 66.2±19.1 years; the average preoperative IOP was 33.2±11.1 mm Hg on 4.2±1.3 IOP-lowering agents before GDD surgery. IOP decreased significantly to 14.1±4.7 mm Hg (P<0.001) on 1.6±1.2 IOP-lowering agents (P<0.001) after an average follow-up of 18.2±15.4 months. There were no cases of early or late blebitis or endophthalmitis, and there was 1 case of conjunctival erosion and tube/plate exposure (1.6%) occurring 30 days after surgery. Qualified success was estimated as 90.5% and 81% at 1 and 2 years, respectively, using Tube Versus Trabeculectomy study criteria.

CONCLUSIONS

Heterologous, fresh, human donor sclera appears to be a safe material for GDD tube coverage. It provides a cost-efficient alternative compared with traditional patch graft materials associated with a low risk of pathogen transmission.

Patch graft materials for glaucoma tube implants

PURPOSE OF REVIEW

Patch graft materials serve multiple purposes in glaucoma surgery. There are several choices of patch graft materials from which the surgeon can choose. Therefore, knowledge as to the choices and the potential risks and benefits of patch graft materials is imperative for the glaucoma surgeon.

RECENT FINDINGS

Recent studies evaluate both patch graft materials and techniques. This evaluation is timely as facility reimbursement changes may also impact utilization and technique.

SUMMARY

Successful operative outcomes require profound understanding of all potential risks and benefits of patch graft materials and surgical techniques.

Clinical outcomes of gamma-irradiated sterile cornea in aqueous drainage device surgery: a multicenter retrospective study

PurposeThe purpose of the study was to evaluate the safety and efficacy of gamma-irradiated sterile cornea (GISC) for covering the tube in aqueous drainage device (ADD) surgery in a retrospective, multicenter case series.Patients and methodsParticipants included 297 patients (321 procedures) who had undergone ADD surgery for the first time using GISC patch at three clinic centers in the United States between April 2009 and July 2012. The medical records of those consecutive patients were reviewed. Preoperative, intraoperative, and postoperative parameters about GISC were collected and analyzed. The main outcome measures were patch graft failure (PGF) and postoperative complications related to GISC.ResultsThree hundred and nineteen eyes in 295 patients were included in the current analysis. Ten out of the 319 eyes experienced PGF with a mean follow-up of 15.4±9.8 (SD) months. The overall cumulative PGF proportion from Kaplan-Meier analysis was 2.6% (95% CI: 0.6-4.7%) at 18 months. We detected two cases of presumed endophthalmitis related to PGF.ConclusionsGISC appears to have a reasonable success rate for preventing tube exposure related to PGF over an 18-month period. This success rate, in combination with other features of GISC (transparency and storage at room temperature), makes it a viable choice for patch graft material during ADD.

Sequential versus concomitant surgery of glaucoma drainage implant and Boston keratoprosthesis type 1

PURPOSE

To compare sequential versus concomitant surgery of glaucoma drainage implant (GDI) and Boston keratoprosthesis type 1 (KPro).

METHODS

Patients who received GDI and KPro in the same eye were divided into 2 groups: GDI placement prior to KPro surgery (sequential group) or GDI placement concomitant with KPro surgery (concomitant group). Main outcome measures were GDI failure, defined as intraocular pressure (IOP) &gt;21 mm Hg, less than a 20% IOP reduction from baseline, or IOP &lt;5 mm Hg on 2 consecutive follow-up visits, any reoperation for glaucoma, or loss of light perception; best-corrected visual acuity (BCVA); and surgical complications.

RESULTS

Thirty-five eyes were included in the study: 17 in the sequential group and 18 in the concomitant group. The cumulative incidence of failure after 5 years of follow-up was 23.5% in the sequential group and 27.8% in the concomitant group (p = 0.250). Mean BCVA was significantly better in the concomitant group after 6 months, 1 year, 2 years, and at the last follow-up (p&lt;0.05). Both groups had similar rates of complications (p = 1.000). The most frequent complication was GDI erosion, which occurred in 23.5% (n = 4/17) in the sequential group and in 27.8% (n = 5/18) in the concomitant group (p = 1.000).

CONCLUSIONS

Glaucoma drainage implant placement at the time of KPro surgery had similar cumulative incidence of failure, but significantly favorable visual outcomes, compared to sequential surgeries. The most frequent complication was GDI erosion, occurring in approximately one fourth of the patients.

The use of collagen matrix (Ologen) as a patch graft in glaucoma tube shunt surgery, a retrospective chart review

Purpose: To determine the safety and efficacy of collagen matrix as a patch graft in glaucoma drainage surgery. Collagen matrix grafts may be advantageous because they do not need to be harvested from human donors.

Methods: An institutional, retrospective review of 43 patients with at least 12 months follow-up status post-glaucoma drainage implant surgery were evaluated for signs of tube erosion after initial placement of collagen matrix patch graft.

Results: Forty-one of 43 eyes (95.3%) required no intervention for patch graft melting with tube erosion. Average time of follow-up was 32 months (range: 12-45). Two cases had tube erosion at 4 months and 26 months post-op requiring tube revision, which was successfully revised with conjunctiva (4 month erosion) and donor sclera (26 month erosion).

Conclusion:  Our results suggest that collagen matrix patch grafts may be used successfully as a patch graft in glaucoma tube shunt surgery, and may be advantageous because they do not have to be harvested from human donors. It is possible that exposure rates may be higher after longer follow-up and with larger numbers of patients. Further research is needed to compare Ologen to traditional graft materials to conclusively determine the safety and efficacy of collagen matrix as a novel patch graft material.

Long-term results of viscocanalostomy and phacoviscocanalostomy: a twelve-year follow-up study

AIM

To evaluate the long-term efficacy and safety results of viscocanalostomy and phacoviscocanalostomy.

METHODS

The charts of 49 glaucoma patients who underwent viscocanalostomy or phacoviscocanalostomy surgery between February 1999 and August 2004 were reviewed retrospectively. Thirty-one eyes of 21 glaucoma patients who underwent filtering procedure with a postoperative follow-up of at least 5y were included in the study. Results of complete ophthalmologic examinations were recorded and statistically analyzed. Long-term surgical outcome was defined as an overall success when intraocular pressure (IOP) was found as ≤20 mm Hg with or without antiglaucomatous medication at the last follow-up visit, while it was defined as a complete success when IOP was measured ≤20 mm Hg without antiglaucomatous medication.

RESULTS

Mean age was 68.1±9.6y (range: 32-81y). Mean follow-up time was 101.5±27.3mo (range: 60-144mo). Viscocanalostomy was performed in 8 eyes (25.8%) and phacoviscocanalostomy was performed in 23 eyes (74.2%). The mean preoperative IOP was 23.1±7.6 mm Hg with 2.1±1.0 medications, while mean IOP was 16.8±3.8 mm Hg with 0.9±1.1 medication at the last follow-up visit. Both the IOP decrease and the reduction in the antiglaucomatous medication were statistically significant (P<0.001 and P<0.001). No case required further glaucoma surgery. Overall success and complete success were found as 87.1% and 51.6%, respectively. Complete success rate was statistically higher in phacoviscocanalostomy group compared with the viscocanalostomy group (P=0.031), however there was no significant difference in overall success rate between two groups (P=0.072).

CONCLUSION

Both viscocanalostomy and phacoviscocanalostomy provide good IOP reduction in the long-term period.

The use of irradiated corneal patch grafts in pediatric Ahmed drainage implant surgery

PURPOSE

To describe the use of irradiated cornea for scleral reinforcement in Ahmed glaucoma valve drainage implant (AGV) devices in children.

METHODS

The medical records of patients <18 years of age who underwent AGV surgery with irradiated cornea as scleral reinforcement were reviewed retrospectively. The primary outcome measure was erosion of the drainage tube through the corneal patch graft. Secondary outcome measures included other major complications: persistent inflammation, wound dehiscence, transmission of infectious disease, endophthalmitis, and tube/plate self-explantation.

RESULTS

A total of 25 procedures (20 patients) met inclusion criteria. Average patient age was 70 months (range, 2 months to 17 years). Mean follow-up was 24.8 months (range, 6 months to 6.2 years). One tube experienced conjunctival exposure through two separate corneal grafts (2/25 cases [8%]), sequentially in the same eye. The first event occurred at month 3.5 after primary implantation of the tube shunt; the second erosion occurred following revision of the existing implant at month 1.5 postoperatively. There were 2 cases of auto-explantation, 2 cases of wound dehiscence, and 1 case of persistent inflammation. There were no cases of endophthalmitis or other infections.

CONCLUSIONS

To our knowledge, this is the first report describing the use of corneal patch grafts in children. Irradiated cornea improves cosmesis and enhances visualization of the tube. The risk of tube exposure was found to be low and comparable to other materials used as a patch graft.