Viscocanalostomy Research Articles

Viscocanalostomy and combined phacoemulsification with viscocanalostomy: A five-year follow-up.

Purpose:To assess the effectiveness and safety of viscocanalostomy (VC) and phaco-viscocanalostomy (PV) surgeries in eyes with a five-year follow-up.Methods:Retrospective review of patients who underwent VC and PV between January 2010 and December 2012 in the Stanley Eye Unit Abergele, UK. Patients were included for the analysis if they had a full 5-year follow-up or required redo surgery in the 5-year period. Success was defined as an intraocular pressure (IOP) of <21 mmHg. The subanalysis included IOP <16 mmHg, IOP reduction >20%, and IOP reduction >30%, the complication rate, and the drop in the use of glaucoma medications post-surgery.Results:A total of 370 eyes from 303 patients were included for the analysis. The mean preoperative IOP was 23 mmHg ± 5.3 mmHg with an average of 3.0 ± 0.1 medications. By year 5, this was reduced to 14.3 mmHg ± 6.5 mmHg with a mean of 1.0+/- 0.9 medications; 47.8% of the eyes had an IOP of <21 mmHg by year 5 without medication with a total of 92.6% of the eyes reaching this target with medication. The main complication in this group was the perforation of the Trabeculo Descemet’s Window (TDW) but this was not associated with a poorer outcome.Conclusion:This large data set of eyes undergoing VC surgery demonstrates the effectiveness and safety of this technique over 5 years.

Long-term Results of Nd:YAG Goniopuncture on Viscocanalostomy and Phacoviscocanalostomy.

Laser goniopuncture (LGP) is an effective outpatient procedure which has been shown to maintain reduced intraocular pressure (IOP) 5 years following initial laser treatment in patients who have had viscocanalostomy (VC) (with or without phacoemulsification). The purpose of this study was to establish the long term (5 y) efficacy of neodymium-doped:yttrium aluminum-garnet LGP to lower IOP following VC or phacoviscocanalostomy (PVC) in patients with glaucoma. This retrospective study analyzed patients who underwent LGP following VC±phacoemulsification between 2009 and 2012 at the Stanley Eye Unit in Abergele. Reason for further intervention included either increasing IOP outside target range or worsening visual fields. Statistical analyses were performed comparing pregoniopucture values to those taken up to 5 years later. Of the 620 VC and PVC procedures performed between 2009 and 2012, 218 eyes underwent LGP after a mean of 25 months [95% confidence interval (CI): 22.58 to 27.41] following surgery. Patients having a PVC had a longer mean time to goniopuncture compared with those who were phakic and had VC only (P<0.001). Immediately following goniopuncture IOP dropped, and a statistically significant reduction persisted at 5 year follow-up (P<0.001). Goniopuncture reduced IOP significantly from a pretreatment value of 21 to 15 mm Hg over 5 years (95% CI) (χ2F(4)=119.1, P<0.001). In total, 154 eyes (71%) were commenced on IOP-lowering medication at a mean of 14 months (95% CI: 12 to 17). At 5 years, successful IOP control was achieved in 73% (49 of 67) of eyes. There was no difference found between type of surgery and successful pressure control at 5 years (χ2(1)=2.00, P=0.16). LGP is an effective procedure which maintains a statistically significant reduction in IOP in the long term.

Evaluating the long-term efficacy and effectiveness of Viscocanalostomy and combined phacoemulsification with Viscocanalostomy in the treatment of patients with uveitic glaucoma: 5-year follow up data

BackgroundUveitic glaucoma commonly leads to a more intense optic nerve damage than other types of glaucoma, causing glaucomatous optic nerves and visual field defects. Anterior uveitis is the most commonly associated risk factor. Surgical intervention is usually indicated when all medical treatment has failed. We report five-year results for 16 eyes of uveitic glaucoma managed with viscocanalostomy (VC)/Phaco viscocanalostomy (PVC).MethodsRetrospective analysis on all uveitic glaucoma cases meeting a five-year follow up was completed. All patients were managed surgically with either viscocanalostomy (VC) or phacoviscocanalostomy (PVC). Outcomes evaluated included intraocular pressures measurement pre-listing, on day 1, year 1 to year 5. Complete success rate was defined as achieving an intraocular pressure (IOP) lower than 21 mmHg or reduced by 30% without medications, and qualified success was achieved when IOP was lower than 21 mmHg or a reduction in IOP of 30% with topical medical therapy ± Laser goniopuncture (LGP). If further surgeries were required to reduce IOP due to glaucoma progression then they were classified as a failure.ResultsA total of 16 patients with uveitic glaucoma were reviewed. Complete success was seen in 75% of patients at year 1, 50% of patients at year 3 and 19% of patients in year 5. Conversely qualified success was achieved in 94% of patients at year 1, 86% of patients at year 3 and 75% of patients at year 5. In the group of patients requiring further surgery, 50% of patients had previous surgeries, including cataract surgery, trabeculectomy and viscocanalostomy. There was a mean number of 4 pre-operative drops before their primary surgery and a mean drop in eye medications of 1.1 at 5 years follow-up. Success rates were prognostically linked to lower mean number of interventions and lower percentage of previous surgeries.ConclusionThere remains a significant paucity of information in the utilization of PVC in uveitic glaucoma. The advantage of nonpenetrating glaucoma surgery (NPGS) includes the lack of entry into the anterior chamber and the avoidance of an iridectomy which may reduce intraocular inflammation and postoperative complications. Our study shows that non-penetrating surgery is successful in treating advanced uveitic glaucoma.

Outcomes of viscocanalostomy and phaco-viscocanalostomy in patients with advanced glaucoma

PurposeTo determine the medium-term outcomes for patients with advanced glaucoma undergoing viscocanalostomy.MethodsAll patients with advanced glaucoma (mean deviation (MD) − 12.00 dB or above) and patients with poor visual acuity secondary to advanced glaucoma which precluded formal visual field assessment undergoing viscocanalostomy (VC) and phaco-viscocanalostomy between 2010 and 2014 under the care of a single surgical team were included. Intraocular pressure (IOP), visual acuity (VA) and visual field outcomes were assessed from data prospectively collected into a surgical outcome database. Success was defined at two IOP cut-off points: IOP ≤ 21 and ≤ 16 mmHg with (qualified) or without (complete) medications.ResultsOne hundred thirty-five patients were included. Mean IOP changed from 23.6 ± 6.4 mmHg pre-operatively to 15.3, 15.8 and 14.8 mmHg at 1, 2 and 3 years, a change of 35, 33.5 and 39% respectively. Qualified success for an IOP ≤ 21 mmHg was achieved in 95.66, 90.6 and 80% and complete success in 52.5, 48.6 and 30.6% at year 1, 2 and 3. Qualified success for an IOP ≤ 16 mmHg was achieved in 66.6, 66.05 and 60% and complete success in 44.8, 37.6 and 30.6% at year 1, 2 and 3. The cumulative probability for achieving an IOP ≤ 21 mmHg with or without drops was 86.1, 81.4 and 81.4% at 12, 24 and 36 months. Eleven patients (8.1%) failed to achieve adequate IOP control and needed further surgical intervention. Eleven (8.1%) patients needed an intervention (Yag goniopuncture) following VC. Four patients (2.9%) had some post-operative complications, which resolved within 2 weeks following surgery. Nine patients (6.7%) lost more than 2 Snellen lines. There was no significant change in the MD across time points.ConclusionViscocanalostomy and viscocanalostomy combined with phacoemulsification is a safe and effective method of controlling IOP in the medium term in patients with advanced glaucoma.

The efficacy of Viscocanalostomies and combined phacoemulsification with Viscocanalostomies in the treatment of patients with glaucoma: a non-randomised observational study

BackgroundTo evaluate the outcomes of Viscocanalostomy (VC) and Phacoviscocanalostomy (PV) in controlling primary and secondary glaucoma in a large cohort of patients from a single eye unit and performed by a single surgeon.MethodsThis non-randomised, retrospective study was conducted on 620 eyes of 458 patients. All patients who had either viscocanalostomy (VC) or combined phacoemulsification and viscocanalostomy (PV) over a three-year period were included. Intraocular pressures (IOP), number of anti-glaucoma medications used, and any complications were recorded over a 3-year follow up period.Paired T-Test was used to compare preoperative and post-operative IOP at specified time points. Kaplan–Meier survival models were used to determine success rates over the study period.ResultsSix hundred twenty procedures were performed during the 3-year study period, of which 427 were PV and 193 VC. The mean follow-up was 31.8 months. Overall complete success (IOP ≤ 21 mmHg, without medication) at 3 years was achieved in 65.7% of patients, with qualified success (IOP ≤21 mmHg with or without medication) achieved in 96.0%. Subgroup analysis showed complete success rate of 76.0% for PV and 63.1% for VC (p = 0.005), with qualified success 95.9% for PV and 94.0% for VC (p = 0.668).Mean pre-operative IOP (mmHg) for all procedures was 23.02 ± 5.6, with PV and VC subgroups at 22.54 ± 5.10 and 24.06 ± 6.45. Post-operatively IOP at month 12 and 36 was 14.74 ± 3.57 and 14.40 ± 3.17 respectively for all procedures, 14.62 ± 3.26 and 14.44 ± 3.10 for PV, and 15.03 ± 4.18 and 14.31 ± 3.33 for VC.Across all procedures, pre-operatively an average of 3.05 ± 0.96 anti-glaucoma medications were used. This reduced to 0.13 ± 0.39 in 12 months and 0.38 + 0.71 by 36 months.Sixty-five cases had complications due to trabeculo-Descemet window perforation during viscocanalostomy with 7 cases developing complications from the cataract element. In the 12.9% of patients who had complications there were no differences of IOP noted at 3 years.ConclusionVC and PV have good IOP lowering capacity and are both effective at sustaining a reduction in IOP at 3 years. PV achieved a higher success rate without medication. The low complication profile with reduced post-operative care means these procedures may be a preferred option for early surgical intervention.

Postoperative outcomes following trabeculectomy and nonpenetrating surgical procedures: a 5-year longitudinal study.

PurposeTo assess and compare the long-term postoperative outcomes of trabeculectomy (TE), phacotrabeculectomy (PTE), and viscocanalostomy (VC) and to correlate postoperative intraocular pressure (IOP) with visual outcome.Patients and methodsThis retrospective cohort observational study included 520 eyes which underwent TE with mitomycin C (MMC) (n=205), PTE with MMC (n=189), and VC ± combined cataract surgery and MMC (n=126) to control IOP between June 2010 and June 2014 by a single surgeon. Complete success was defined as postoperative IOP <20 mmHg, and qualified success with IOP <20 mmHg with single topical agent. Cases requiring more than one topical agent and/or repeat surgery were considered as failure. Mixed linear regression models were constructed to determine estimated predictive values of demographic data, topical prescriptions, baseline and postoperative IOP, and optical assessment (ie, best-corrected visual acuity and mean deviation) profile.ResultsFollow-up ranged from 12 to 66 months (mean 26 months). At last follow-up, 139 (93.9%), 118 (91.5%), and 98 (94.2%) eyes achieved complete success in TE, PTE, and VC groups, respectively (p=0.0007). Failure rates were 2.7%, 3.9%, and 2.9% following TE, PTE, and VC, respectively (p=0.0052). The between-group difference of mean IOP reduction was greater in the short term (p=0.0002). Good postoperative IOP control correlates to optical outcomes reflected by best-corrected visual acuity and mean deviation following TE (β = −4.7577, p=0.0384) and PTE (β = −4.5083, p=0.02741).ConclusionSignificant association was observed between good postoperative IOP control and optical outcome. TE remains the more effective surgical intervention for sustained lowering of IOP. Most complications were transient and self-limiting.

Efficacy of nonpenetrating glaucoma surgery in the treatment of open angle glaucoma：a systematic review

Objective To evaluate the intraocular pressure(IOP)-lowering effects achieved by nonpenetrating glaucoma surgery(NPGS)in patients with open angle glaucoma.Methods Randomized controlled trials evaluating patients with primary and secondary open angle glaucoma treated with NPGS were identified and were subjected to systematic review analysis.The main outcome measurements included the percentage of IOP reduction and the complete success rate.The pooled estimates were calculated using the random effect model by comprehensive meta-analysis software version 2.0.Results Both deep sclerectomy(DS)and viscocanalostomy(VCO)were less effective than trabeculectomy(TE)in lowering IOP,with the of IOP reduction percent at 2years being 35.2%for DS,30.2%for VCO,and 45.6%for TE.Intraoperative use of implants and mitomycin C(MMC)improved IOP-lowering effects of DS,with IOP reduction at percent 2years being 41.1%and 41.7%, respectively.The complete success rates at 4years were 35.4%for DS and 22.7%for VCO,lower than that of TE(47.6%). The complete success rates of DS with implants and MMC were 64.6%and 52.1%at 4years,respectively,both being higher than that of primary DS.NPGS caused less complications than TE.Conclusion Primary deep sclerectomy and primary viscocanalostomy can significantly lower IOP and have less complication than TE.However,the IOP-lowering effect of NPGS is slighter than primary TE.The efficacy of DS can be improved by intraoperative use of implants and MMC.

Systematic overview of the efficacy of nonpenetrating glaucoma surgery in the treatment of open angle glaucoma

SummaryBackgroundTo evaluate the intraocular pressure (IOP)-lowering effects achieved by nonpenetrating glaucoma surgery (NPGS) and its modifications in patients with open angle glaucoma.Material/MethodsRandomized controlled trials evaluating patients with primary and secondary open angle glaucoma treated with NPGS were identified through systematic searches. The main outcome measures were the percentage IOP reduction and the complete success rate. Complete success was defined as target endpoint IOP (usually less than 21 mm Hg) without medications. The pooled estimates were calculated using the random effects model.ResultsBoth deep sclerectomy (DS) and viscocanalostomy (VCO) were less effective than trabeculectomy (TE) in lowering IOP, with the percentage IOP reductions at 2 years being 35.2% for DS, 30.2% for VCO, and 45.6% for TE. Intraoperative use of implants and mitomycin C (MMC) increased IOP-lowering effects of DS, with IOP reductions at 2 years of 41.1% and 41.7%, respectively. The complete success rates at 4 years were 35.4% for DS, and 22.7% for VCO, lower than that of TE (47.6%). The complete success rates of DS with implants and MMC of 64.6% and 52.1%, respectively, at 4 years, were greater than that of primary DS. NPGS caused major complications in fewer patients than did TE.ConclusionsPrimary deep sclerectomy and primary viscocanalostomy, which can significantly lower IOP, were associated with fewer complications than was TE. However, the IOP-lowering effects of both NPGS seem to be lower than that of primary TE. The efficacy of DS can be improved with the intraoperative use of implants and MMC.

Long‐term results of viscocanalostomy in pseudoexfoliative and primary open angle glaucoma

To document the outcome of viscocanalostomy (VC) alone or combined with phacoemulsification (phaco-VC) in eyes with pseudoexfoliation glaucoma (PEXG) and primary open angle glaucoma (POAG). A prospective, comparative study of 314 eyes undergoing VC in two centres over 6 years was conducted. Main outcome measures were: (i) intraocular pressure (IOP) control (complete success was IOP < or = 18 mmHg without medication and failure IOP > 18 mmHg); and (ii) requirement for Nd:YAG laser goniopuncture (YAG-GP) if IOP > 21 mmHg. In the POAG group, 174 eyes underwent phaco-VC and 104 VC. In the PEX group, 20 eyes underwent phaco-VC and 16 VC. At final follow up, complete success rate (CSR) was 76% for POAG phaco-VC, 67% for POAG VC, 95% for PEXG phaco-VC and 63% for PEXG VC with mean IOP reduction of 29.9%, 40%, 42.5% and 51%, respectively. Without YAG-GP, by 3 years postoperatively the failure rate was 100% for PEXG eyes and 21% for POAG eyes undergoing VC alone, but PEXG eyes undergoing phaco-VC were 100% successful. CSR for YAG-GP was 92% in PEXG VC eyes and 55% in POAG VC eyes. In phakic eyes with PEXG undergoing VC, an absolute requirement for long-term success was YAG-GP. This was not the case in POAG eyes or PEXG eyes undergoing phaco-VC. Late IOP rise in phakic PEXG eyes and restoration of IOP control following YAG-GP suggests that continued release of PEX material from the lens capsule with time blocks the outflow through the trabecular-Descemetic window created by VC.

Nonpenetrating Glaucoma Surgery: Meta-analysis of Recent Results

To evaluate the efficacy of nonpenetrating glaucoma surgery for open angle glaucoma with respect to target intraocular pressure (IOP) and severity of glaucoma. A literature search with the terms "nonpenetrating glaucoma surgery, deep sclerectomy (DS), viscocanalostomy (VC), and open angle glaucoma" was carried out for the reports in the last 5 years. Studies encompassing only combined glaucoma and cataract surgery were excluded. Measurement of effectiveness was determined on the basis of achievement of target IOP. Data related to postoperative goniopuncture and needling with antimetabolite application were noted. The percentage of cases achieving <or=21 mm Hg was 48.6% after primary DS, 68.7% after DS with implant, 67.1% after DS with antimetabolite, 51.1% after primary VC, and 36.8% after VC with antimetabolite or implant. Visual field parameters were almost exclusively not available; whereas cup/disk ratio and target IOP lower than 21 mm Hg were available in very few reports. With lower set IOP targets, the rates of success varied between 35% and 86% for DS, and between 10% and 67% for VC. The mean follow-up of the studies were mostly in the range of 3 years. Nonpenetrating glaucoma surgery seems to provide IOP reduction into the high teens. Its potential to achieve lower target IOPs seems to be low. Longer-term studies, with data related to glaucoma severity and proper target IOPs are required.

Viscocanalostomy with Mitomycin-C: A Preliminary Study

To compare the results of viscocanalostomy with and without mitomycin-C (MMC). Retrospective results of 15 standard viscocanalostomy (VCO) operations (Group 1) were compared with the prospective results of 15 VCO operations performed with intraoperative adjunctive MMC (Group 2). MMC (0.2 mg/mL) was applied over and under the superficial scleral flap for 3 minutes in Group 2 before the deep flap was prepared. Each patient was followed up for at least 1 year, and results of examinations in the first 12 months were used in the statistical comparison of the two groups. Surgical success was defined as intraocular pressure (IOP) < or = 18 mmHg. Preoperative mean intraocular pressures (IOP) in Group 1 and Group 2 were 35.3+/-11.0 and 39.1+/-8.9, respectively. Mean IOP levels at the 12th month were 14.4+/-2.6 and 11.9+/-4.0, respectively, showing a significant decrease in both groups (p<0.001). Postoperative IOP course appeared to be lower in the MMC group, however, the difference was not statistically significant (p=0.554). Complete success rates without medications were 40% in Group 1 and 67% in Group 2. No significant difference was found between the two groups in terms of early and late postoperative complications, pre- and postoperative number of antiglaucoma medications, and surgical success rates at the end of the study period (p>0.05 for all). A significant difference was verified between the two groups of eyes considering the conjunctival bleb types, as low-lying, localized blebs were the most frequent type in Group 1 and thin-walled, avascular blebs were more predominant in the MMC group (p=0.004). Intraoperative adjunctive MMC use might improve the long-term results of viscocanalostomy by facilitating subconjunctival filtration and might widen the indication range of the technique.

Two cases of intraoperative anterior chamber angle observation using ophthalmic endoscope in viscocanalostomy

To report endoscopic findings in the anterior chamber angle during injection of viscoelastic material in viscocanalostomy (VCS). Observational case reports. Two cases of primary open-angle glaucoma were treated with VCS and cataract surgery. Immediately before and during injection of viscoelastic material into Schlemm's canal, the anterior chamber angle was observed using an ophthalmic endoscope. In both cases, we observed viscoelastic material in Schlemm's canal and leakage of viscoelastic material and blood from Schlemm's canal into the anterior chamber away from the injection site of the viscoelastic material. In one case, indocyanine green-stained viscoelastic material was not in Schlemm's canal the day after surgery. In VCS, Schlemm's canal was filled and was disrupted after viscoelastic material injection. Disruption of the inner wall of Schlemm's canal and juxtacanalicular connective tissues may contribute to the intraocular pressure reduction associated with VCS.

Viscocanalostomy Versus Trabeculectomy in Patients with Bilateral High-tension Glaucoma

Results of trabeculectomy (TE) and viscocanalostomy (VCO) were compared in a prospective randomised study in two fellow eyes of 22 consecutive patients with bilateral symmetrical high-tension glaucoma. Rates of overall surgical success with intraocular pressures (IOP) < or = 18 mm Hg with or without medications were 91 for the TE, and 95 for the VCO group after a mean follow-up of 18 months. Complete success rates without medications were 64 and 59 for TE and VCO groups, respectively (p = 0.750). Both procedures significantly reduced IOP, however, IOP course following trabeculectomy was significantly lower (p = 0.026). Rates of complications were not found to be different between the two groups of eyes, except for an apparent--though not significant (p = 0.066)--increase in cataract progression with TE. Various types of conjunctival blebs were detected in all eyes with surgical success in both groups, however, diffuse, elevated or multi-cystic functional blebs appeared to be more predominant in eyes with TE, compared to the VCO group in which low-lying, localised blebs had a higher incidence (p = 0.015). Viscocanalostomy was found to be a safe and effective filtration technique in patients with uncomplicated high-tension glaucoma, though IOP decrease was more pronounced with trabeculectomy.

Comparison of surgical outcomes of combined viscocanalostomy and cataract surgery with combined trabeculotomy and cataract surgery

PURPOSE: To compare the outcomes of combined viscocanalostomy, phacoemulsification, and intraocular lens (IOL) implantation with combined trabeculotomy, phacoemulsification, and IOL implantation in patients with primary open-angle glaucoma (POAG). DESIGN: Nonrandomized clinical trial. METHODS: Fifty-seven eyes (57 POAG patients) that underwent viscocanalostomy, phacoemulsification, and intraocular lens (IOL) implantation between March 2000 and April 2001 and were followed for over 6 months postoperatively comprised the viscocanalostomy (VCS) group. Fifty-seven of 105 eyes (105 POAG patients) that underwent trabeculotomy, phacoemulsification, and IOL implantation between April 1995 and February 2000 and were followed for over 6 months and < 2 years comprised the trabeculotomy (LOT) group. The reductions of postoperative intraocular pressure (IOP) and antiglaucoma medication use in both groups were compared. Best-corrected visual acuity (VA) and complication rates were secondary outcomes. The success probabilities related to postoperative IOP level in both groups were evaluated by Kaplan-Meier life-table analysis with log-rank test. RESULTS: Significant reductions of IOP and antiglaucoma medication use occurred in both groups up to 1 year postoperatively, but were not significantly different between the two groups. The success probabilities of the VCS group for IOP control under 21, 17, and 15 mm Hg were 95%, 74%, and 44%, respectively, at 6 months, 95%, 67%, and 32% at 1 year, and not significantly different from the LOT group. All eyes in the VCS group had VA equal to or better than baseline 3 months postoperatively. The incidences of postoperative fibrin reaction (14 eyes, 25%) and microperforations of the Descemet membrane (14 eyes, 25%) in the VCS group were higher than in the LOT group ( P = .0004 and P < .0001, respectively). CONCLUSIONS: Intraocular pressure reduction and VA improvement after the two procedures were similar in Japanese patients with POAG and cataract.

Nonpenetrating Filtering Procedures: Viscocanalostomy and Collagen Wick

Unroofing of Schlemm's canal without entering the anterior chamber has been performed previously to lower intraocular pressure. Initial results were good, but long-term results were discouraging, and the techniques were abandoned. Recently, two variations have surfaced. Visco canalostomy is a technique devised by Robert Stegmann of South Africa, The glaucoma drainage device (Collagen Wick) was initially introduced by Koslov in Russia. These techniques are described in this article. Copyright © 1999 by W.B. Saunders Company