Effectiveness of trabeculectomy in glaucoma

[Glaucoma Filtration Surgery - Bleb-forming Procedures]

Glaucoma filtration surgery has been a standard surgical therapy for decades. An increasing knowledge about wound healing processes in the eye, the introduction of antimetabolite treatment and continuous improvements of the surgical technique helped making trabeculectomy - the prototype filtration surgery - a very effective therapeutic tool. However, best results will only be regularly achieved with a high level of experience and time dedicated to postoperative follow-up. Furthermore, the potential for severe early and late complications still remains high. Thus, novel stent-based filtration surgery approaches, such as the Preserflo and the XEN shunt have been introduced. This review presents these three bleb-forming filtration procedures, covering the basic principles of surgical technique, data on effectivity as well as complications.

Comparison of Trabeculectomy Outcomes Performed by Residents in Training and Ophthalmologists

PRCIS

Resident-performed trabeculectomies present higher intraocular pressure and lower complete success rate at 1 year.

PURPOSE

To compare the 1-year outcomes of ab externo trabeculectomy between residents in training and staff ophthalmologists.

PATIENTS AND METHODS

This retrospective study included all consecutive eyes submitted to ab externo trabeculectomy between January 2015 to June 2020. A 1-year complete success rate was considered using all the following criteria: intraocular pressure (IOP)≤21 mm Hg and ≥6mm Hg without ocular hypotensive medications; IOP reduction≥30%; without loss of light perception, phthisis bulbi, and further glaucoma surgery (excluding suture lysis and bleb needling).

RESULTS

One hundred and ten eyes from 99 patients were included. Thirty percent (n=33) of the trabeculectomies were performed by residents. There were no significant preoperative differences between groups, apart from age at surgery, which was higher in the residents' group (72.39±6.83 vs. 62.00±15.07 years, P<0.001), and visual field index (Humphrey Field Analyzer), which was lower in the ophthalmologists' group (51.81±34.74% vs. 32.04±33.83%, P=0.013). IOP at 1-, 3-, 6 months, and 1 year after surgery was significantly higher in the resident's group (P<0.05). Resident-performed trabeculectomies achieved a significantly lower complete success rate when compared with the ophthalmologists' group (39.39% vs. 64.94%, P=0.013). The overall rate of the postoperative complications and reintervention did not differ between groups, but the occurrence of a shallow anterior chamber was more frequent in the residents' group (15.15% vs. 4.05%, P=0.037).

CONCLUSIONS

Resident-performed trabeculectomies present significantly higher postoperative IOP levels and a lower complete success rate when compared with staff ophthalmologists. It is, therefore, fundamental to adopt strategies to change this gap, improve patient safety, and strengthen resident confidence.

Filtering Bleb Size in the Early Postoperative Period Affects the Long-term Surgical Outcome after Trabeculectomy

PURPOSE

To investigate whether postoperative filtering bleb size affects the surgical outcome after trabeculectomy.

METHODS

In this study, we retrospectively reviewed 145 medically uncontrolled glaucoma patients with intraocular pressure (IOP) values >21 mmHg before surgery and data from ≥2 years of follow-up. Postoperative IOP, filtering bleb size including extent and height, and other clinical factors were measured after trabeculectomy. We divided bleb extent into quadrants and bleb height by 0.5 intervals of corneal thickness. The main outcome measure was surgical success. We confirmed complete success when the IOP was ≤21 mmHg and decreased by >20% from baseline without medication or additional procedures. Qualified success used the same criteria but allowed for medication or additional procedures. Cases with reoperation or two consecutive IOP measurements <6 mmHg were considered failures.

RESULTS

A total of 145 eyes of 145 patients was included. The average observation period was 30.8 ± 10.9 months. During multivariate Cox regression analysis, a larger extent of filtering bleb revealed significantly low hazard ratios in both complete and surgical success (0.509 and 0.494, respectively); however, there was no significant relationship between bleb height and surgical outcome.

CONCLUSIONS

The extent of the filtering bleb was associated with surgical outcomes of trabeculectomy in glaucoma patients.

Trabeculectomy with Ologen implant versus trabeculectomy with P 50 Ex-PRESS shunt in primary open-angle glaucoma

Background

This is the first randomized controlled trial of trabeculectomy with Ex-Press Shunt versus Ologen implant in primary open-angle glaucoma (POAG) in Indian eyes.

Methods

A prospective randomized controlled trial of patients of POAG treated with two different methods of augmented trabeculectomy. Group A with Ex-PRESS shunt (P50 model) and Group B with Ologen implant. Surgical success was defined as intraocular pressure of 21 mm Hg or lower at 6 months postoperative.

Results

N = 40 eyes of 33 patients. Baseline IOP in Group A was 23.70 ± 4.6 mm Hg (Range 22-36 mm Hg), and Group B was 26.00 ± 4.0 mm Hg (Range 23-36 mm Hg). Surgical success was achieved in 85% of patients in both Groups. Change in IOP from baseline was statistically significant in both groups at 1, 4, 8, 12 weeks, and 6 months postoperative. No statistically significant difference in the change in IOP between the two groups. Postoperative complications were lesser in Group A compared to Group B, in both early (35% vs 50%) and late stage (20% vs 30%). The drop in visual acuity became statistically insignificant at 4 weeks in Group A and 8 weeks in Group B.

Conclusions

There is no difference between the surgical success rates of trabeculectomy with Ex-PRESS Shunt versus Ologen. However, the Ex-PRESS shunt fares better with lower complication rates and faster visual recovery than the Ologen group.

Trabeculectomy: Does It Have a Future?

The trabeculectomy (TRAB) procedure has undergone various modifications to increase the long-term surgical success and safety profiles. The main issues with TRAB include short and long-term complications, that are more common with the concomitant use of anti-fibrotic agents. While many surgeons have predicted the demise of trabeculectomy amidst newer non-penetrating glaucoma surgeries, it is still the gold standard procedure for patients with an advanced or rapidly progressing disease and for those patients who need very low intraocular pressures. This review article is unique in summarizing the evolution of trabeculectomy and its efficacy compared to neoteric shunt procedures while trying to predict if trabeculectomy has a future in the modern surgical world. We have compared the outcomes and complications of trabeculectomy to all the surgical procedures available to date and have tried to evolve an algorithm to help surgeons to decide on their preferred technique.

Cross-linked hyaluronic acid viscoelastic scleral implant in trabeculectomy

Purpose:

Patients with glaucoma undergoing trabeculectomy develop bleb cicatrix causing poor postoperative intraocular pressure (IOP) control and low success rates. Several approaches have been explored over the years for better outcomes. This study assesses the safety, efficacy, and outcome of trabeculectomy with HealaFlow^® (Anteis S. A, Geneva, Switzerland), a high-molecular-weight cross-linked hyaluronic acid viscoelastic gel, and comparing it with the antimetabolite Mitomycin-C (MMC).

Methods:

A prospective, interventional, case-controlled study conducted at a tertiary care hospital in Southern India on 60 eyes of patients requiring trabeculectomy divided in two groups – HealaFlow scleral implant and adjuvant low-dose MMC (0.1 mg/mL). Postoperative IOP reduction along with bleb morphology was assessed over follow-up at 1 week, 1 month, 3 months, 6 months, and 12 months.

Results:

Preoperatively IOP in the two groups was statistically similar. Postoperative IOP on day 1 had statistically significant reduction in both groups with greater reduction in MMC group. However, by 12 months, the IOP reduction was statistically similar in both groups, i.e., 46.24% (to 11.04 ± 2.55 mmHg) and 54.47% (to 11.99 ± 3.37 mmHg) in HealaFlow^® group and MMC group, respectively (P > 0.05). The bleb morphologies were similar and complications were seen equally, which resolved by 4 weeks. A complete success rate of 89.29% and a qualified success rate of 10.71% were observed equally in both groups.

Conclusion:

Absorbable biosynthetic cross-linked hyaluronic acid and low-dose MMC are equally safe and efficacious in trabeculectomy with significant IOP reduction and good bleb morphology. Therefore, it is a novel substitute for MMC.

Effects of Miosis on Anterior Chamber Structure in Glaucoma Implant Surgery

We investigated changes in anterior chamber (AC) structure after miosis in phakic eyes and pseudophakic eyes with glaucoma. In this prospective study, patients scheduled for glaucoma implant surgery were examined using anterior segment optical coherence tomography before and after miosis. Four AC parameters (AC angle, peripheral anterior chamber (PAC) depth, central anterior chamber (CAC) depth, and AC area) were analyzed before and after miosis, and then compared between phakic and pseudophakic eyes. Twenty-nine phakic eyes and 36 pseudophakic eyes were enrolled. The AC angle widened after miosis in both the phakia and pseudophakia groups (p = 0.019 and p < 0.001, respectively). In the phakia group, CAC depth (p < 0.001) and AC area (p = 0.02) were significantly reduced after miosis, and the reductions in PAC depth, CAC depth, and AC area were significantly greater than in the pseudophakia group (all p < 0.05). Twenty-five patients (86.2%) in the phakia group and 17 (47.2%) in the pseudophakia group had reduced CAC depth (p = 0.004). Although miosis increased the AC angle in both groups, AC depth decreased in most phakic eyes and a substantial number of pseudophakic eyes. Preoperative miosis before glaucoma implant surgery may interfere with implant tube placement distant from the cornea during insertion into the AC.

A Comparison of Trabeculectomy Surgery Outcomes With Mitomycin-C Applied by Intra-Tenon Injection Versus Sponge

PURPOSE

To compare the outcomes of mitomycin-C (MMC) delivered by intra-Tenon injection vs sponge application during trabeculectomy surgery.

METHODS

We retrospectively reviewed 566 patients with primary and secondary glaucoma diagnoses who received trabeculectomy surgery with MMC in an academic medical center. Exclusion criteria were age less than 18 years, no light perception vision, combined surgery, previous glaucoma incisional surgery, intraoperative 5-fluorouracil, or follow-up <1 month. Subjects were divided into 2 cohorts: MMC delivered by sponge application or by intra-Tenon injection. Main outcome measures were postoperative intraocular pressure (IOP) level and secondary measures were survival rate for IOP control, glaucoma medication use, complication rate, and vision.

RESULTS

After inclusion/exclusion criteria, 316 eyes were available for analysis; 131 eyes had MMC delivered via sponge and 185 eyes via injection. Mean postoperative IOP was not significantly different between treatment groups but change in IOP from baseline was lower in the sponge vs the injection group 24 months after surgery (P = .038). The MMC sponge group had significantly more tense, vascularized, or encapsulated blebs as a late complication (P = .046). Time to failure for postoperative IOP control was not significantly different between MMC treatment groups, but older patient age and limbus-based conjunctival incision were associated with significantly longer time to fail.

CONCLUSIONS

The application of MMC by injection was similar to application by sponge in lowering IOP in patients with glaucoma and the safety of both techniques appears to be comparable. Limbus-based conjunctival incision had longer time to failure for postoperative IOP control vs fornix-based incision. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Treatment choices for newly diagnosed primary open angle and ocular hypertension patients

Despite advances in our knowledge of the aetiology and pathophysiology of glaucoma, the sole proven, effective intervention for treating primary open-angle glaucoma (POAG) and ocular hypertension (OHT) remains lowering of intraocular pressure (IOP) to prevent further progression and visual loss. The purpose of this review is to evaluate the treatment choices available to newly diagnosed POAG and OHT patients. We review the existing literature on treatments currently available to newly diagnosed POAG and OHT patients and discuss their role in the treatment paradigm of POAG and OHT. We consider different factors that may be important when offering a choice of treatment to newly diagnosed POAG and OHT patients as well as describing new glaucoma treatments in development and future directions for treatment.

Important Metabolites in Maintaining Folate Cycle, Homocysteine, and Polyamine Metabolism Associated with Ranibizumab Treatment in Cultured Human Tenon's Fibroblasts

The anti-fibrotic properties of ranibizumab have been well documented. As an antagonist to vascular endothelial growth factor (VEGF), ranibizumab works by binding and neutralizing all active VEGF-A, thus limiting progressive cell growth and proliferation. Ranibizumab application in ocular diseases has shown remarkable desired effects; however, to date, its antifibrotic mechanism is not well understood. In this study, we identified metabolic changes in ranibizumab-treated human Tenon's fibroblasts (HTFs). Cultured HTFs were treated for 48 h with 0.5 mg/mL of ranibizumab and 0.5 mg/mL control IgG antibody which serves as a negative control. Samples from each group were injected into Agilent 6520 Q-TOF liquid chromatography/mass spectrometer (LC/MS) system to establish the metabolite expression in both ranibizumab treated cells and control group. Data obtained was analyzed using Agilent Mass Hunter Qualitative Analysis software to identify the most regulated metabolite following ranibizumab treatment. At p-value < 0.01 with the cut off value of two-fold change, 31 identified metabolites were found to be significantly upregulated in ranibizumab-treated group, with six of the mostly upregulated having insignificant role in fibroblast cell cycle and wound healing regulations. Meanwhile, 121 identified metabolites that were downregulated, and seven of the mostly downregulated are significantly involved in cell cycle and proliferation. Our findings suggest that ranibizumab abrogates the tissue scarring and wound healing process by regulating the expression of metabolites associated with fibrotic activity. In particular, we found that vitamin Bs are important in maintaining normal folate cycle, nucleotide synthesis, and homocysteine and spermidine metabolism. This study provides an insight into ranibizumab's mechanism of action in HTFs from the perspective of metabolomics.

[Glaucoma surgery: from traditional filtration techniques to modern principles of bioengineering]

The article reviews the history of glaucoma surgery and analyses the connection between the accumulation of knowledge on glaucoma progression and the emergence of effective surgical treatment methods based on glaucoma pathogenesis. It also describes modern principles of preventing filtering bleb scarring. Particular attention is devoted to biodegradable collagen matrix implants.

Impact of Intraocular Pressure after Filtration Surgery on Visual Field Progression in Primary Open-Angle Glaucoma

PURPOSE

To compare visual field progression after trabeculectomy in eyes showing a postoperative intraocular pressure (IOP) less than or equal to 16 mmHg and eyes with an IOP of 17 to 21 mmHg.

METHODS

A retrospective cohort study design was used. A total of 101 eyes of 101 consecutive patients undergoing trabeculectomy for primary open-angle glaucoma (POAG) with a postoperative IOP less than or equal to 21 mmHg were divided into two groups: Group 1 included eyes showing a postoperative IOP less than or equal to 16 mmHg at all visits and Group 2 included eyes with a postoperative IOP between 17 and 21 mmHg. In turn, each of these groups was divided into two subgroups according to whether treatment was required for IOP control. Glaucomatous visual field control during follow-up was compared between the subject groups.

RESULTS

Kaplan-Meier analysis revealed glaucomatous visual field control in 98.53% of the eyes in Group 1 and 89.06% of those in Group 2 at 5 years, the difference between the groups being significant.

CONCLUSIONS

Glaucomatous disease progression is less frequent when IOP is less than or equal to 16 mmHg in all the follow-up visits after trabeculectomy. The results indicate a definite benefit of low IOP in visual field control.

Improving Glaucoma Surgical Outcomes with Adjunct Tools

Conventional glaucoma surgeries, such as trabeculectomy and glaucoma drainage device (GDD) surgery, have been enhanced by surgeons to improve outcome and decrease complications. Over the last two decades, adjuncts, such as collagen matrix implants, fibrin adhesives, and amniotic membrane transplantation (AMT) have been found to be effective in modulating fibrosis and scarring during the wound-healing process, reducing postoperative inflammation, and repairing bleb leakage or conjunctival erosion. The use of these tools provides several advantages when used in trabeculectomy, GDD surgery, and surface reconstruction associated with glaucoma surgery complications. Their use will be discussed in this review. How to cite this article: Lu LJ, Hall L, Liu J. Improving Glaucoma Surgical Outcomes with Adjunct Tools. J Curr Glaucoma Pract 2018;12(1):19-28.

The Influence of Scleral Flap Thickness, Shape, and Sutures on Intraocular Pressure (IOP) and Aqueous Humor Flow Direction in a Trabeculectomy Model

PURPOSE

Intraocular pressure and aqueous humor flow direction determined by the scleral flap immediately after trabeculectomy are critical determinants of the surgical outcome. We used a large-scale model to objectively measure the influence of flap thickness and shape, and suture number and position on pressure difference across the flap and flow of fluid underneath it.

METHODS

The model exploits the principle of dynamic and geometric similarity, so while dimensions were up to 30× greater than actual, the flow had similar properties. Scleral flaps were represented by transparent 0.8- and 1.6-mm-thick silicone sheets on an acrylic plate. Dyed 98% glycerin, representing the aqueous humor was pumped between the sheet and plate, and the equilibrium pressure measured with a pressure transducer. Image analysis based on the principle of dye dilution was performed using MATLAB software.

RESULTS

The pressure drop across the flap was larger with thinner flaps, due to reduced rigidity and resistance. Doubling the surface area of flaps and reducing the number of sutures from 5 to 3 or 2 also resulted in larger pressure drops. Flow direction was affected mainly by suture number and position, it was less toward the sutures and more toward the nearest free edge of the flap. Posterior flow of aqueous humor was promoted by placing sutures along the sides while leaving the posterior edge free.

CONCLUSION

We demonstrate a new physical model which shows how changes in scleral flap thickness and shape, and suture number and position affect pressure and flow in a trabeculectomy.

Is There a Need for New Surgical Procedures for Glaucoma? Yes!

The only method to slow or stop progressive damage caused by glaucoma, the leading cause of irreversible blindness, definitively shown to be effective, is lowering intraocular pressure, though there is also evidence that stabilizing the pressure may be beneficial. Performing surgery on the eye has proven effective in some cases, using various techniques, though with variable frequencies of success (stabilization of the disease) and various frequencies and severities of complications. Surgery offers the great advantage of longer duration of action than medicinal treatments presently available, and, also, of lessening the need of the patient to be faithful using suggested medications. There is a need to develop surgical procedures which will be effective in 1) lowering or stabilizing intraocular pressure in a way most likely to prevent glaucomatous deterioration, 2) causing the fewest and least severe problems, and 3) being the most economical. Recent efforts in this regard are promising, but not yet proven superior to well-performed trabeculectomy, itself an evolving procedure.

Trabecular micro-bypass shunt (iStent®): basic science, clinical, and future)

The trabecular bypass stent offers an alternative to filtration surgery. Patients who may be ideal candidates for considering this procedure are those with prior conjunctival surgery; for example, those who had a 360° peritomy from a scleral buckle might not do well with a trabeculectomy and there is no space for a tube. Highly myopic patients do not tolerate hypotony well, and the iSTB may be an option for some of these patients. I have used the iSTB in patients on anticoagulants who could not stop them, and they needed something beyond medications and laser to lower the IOP in subjects with open-angle glaucoma. Young patients, especially those with one eye, who need rapid visual recovery (for instance to return to work) may be good candidates to consider the iSTB as well. Because of the position used for clear corneal cataract surgery, the temporal approach is best for doing these. Therefore, if you are doing cataract surgery on someone who needs a lower IOP, you already are in the correct position to implant the devices. Patients may need some medications after the procedure to lower the IOP to the level desired. The results from Armenia are encouraging, given an IOP of 11.8 mmHg after 2 iSTB stents and taking daily travoprost. These results are difficult to reach even with a trabeculectomy. When selecting your fist patients, avoid those with the congested episcleral veins, look for patients with wide open angles, and if you can see aqueous veins at the slit-lamp it may indicate a viable outflow system. Probably avoid patients with IOPs over 35 mmHg. The micro-invasive trabecular bypass stents offer an alternative surgical intervention for select patients with open-angle glaucoma. Recent studies show that combining these micro-stents with medications can lead to as low of an intraocular pressure (IOP) as is achieved by many more invasive incisional surgeries. The technique is quite precise and learning the procedure is similar to clear corneal phacoemulsification followed by a goniotomy. Long-term data are starting to come in and the safety is favorable. The IOP success appears to be based on the patency of the outflow system for a given patient. Key factors in determining the success involve the placement of trabecular bypass devices into the canal of Schlemm and require a down-stream patency of the collector channel system and a low episcleral venous pressure. Because accessing the collector system may require placement by a patent channel, the placement of two stents, a longer stent with scaffolding or somehow imaging the outflow system may lead to the best control of the IOP.

Biodegradable Collagen Implants in Trabeculectomy

Subconjunctival and subscleral fibrosis are the major causes of failure of filtering surgery. Antiproliferative agents have been successfully used to improve the long-term success of this surgery. Recent advancement in the field of glaucoma surgery has been the use of bioengineered, biodegradable, porous collagen-glycosaminoglycan matrix implant in the subconjunctival and/or subscleral space to modify the wound-healing process and reduce scar formation, hence improving the surgical success without the need for anti-fibrotic agents. Biodegradable, collagen implants have shown favorable results when used with deep sclerectomy. There have been variable results regarding the success of trabeculectomy when combined with these implants. These implants also decrease the dose of mitomycin C required with trabeculectomy and hence, decrease the side effect associated with these drugs. The use of the biodegradable implants in glaucoma surgery is still evolving and further studies are needed to find the appropriate surgical technique, the ideal size and site of placement and determine their long-term impact on trabeculectomy outcomes and complications. How to cite this article: Ichhpujani P, Dada T, Bhartiya S. Biodegradable Collagen Implants in Trabeculectomy. J Curr Glaucoma Pract 2015;9(1):24-27.

Comparison of outcomes of trabeculectomy with mitomycin C vs. ologen implant in primary glaucoma

Purpose:

To compare the safety and efficacy of trabeculectomy with Ologen implant vs. trabeculectomy with Mitomycin C (MMC).

Materials and Methods:

In a prospective, randomized, pilot study, 39 eyes of 33 subjects with medically uncontrolled primary glaucoma, aged 18 years or above underwent trabeculectomy either with MMC (20 eyes) or with Ologen implant (19 eyes). The primary outcome measure was cumulative success probability, defined as complete if the intraocular pressure (IOP) was > 5 and ≤ 21 mm Hg without anti-glaucoma medications or additional surgery and qualified if an IOP was > 5 and ≤ 21 mm Hg with or without anti-glaucoma medications.

Results:

Mean (± standard deviation) follow-up in Ologen group was 19.1 ± 8.1 months, and in MMC group was 18.0 ± 8.4 months. Mean IOP reduction at 6 months was significantly lower (P = 0.01) in the MMC group (11.9 ± 2.9 mm Hg) as compared to Ologen group (14.6 ± 2.7 mm Hg). However, at 12 months (P = 0.81) and 24 months (P = 0.32), the mean IOP was similar between the 2 groups. Complete success probability at the end of 6 months in Ologen group was 100% (95% confidence interval: 59.1 - 99.0) was similar (P = 0.53) to that in MMC group (93.8%, 95% CI: 63.2 - 99.1). The incidences of early post-operative complications were similar in the 2 groups, except hyphema, which was significantly more in Ologen group (P = 0.02).

Conclusion:

In this pilot study, the success of trabeculectomy and complications were similar in both Ologen and MMC groups at the end of 6 months.

Comparative study of encapsulated blebs following Ahmed glaucoma valve implantation and trabeculectomy with mitomycin-C

Purpose

To compare the histopathologic and morphologic findings of encapsulated blebs following Ahmed glaucoma valve implantation and primary standard trabeculectomy with mitomycin-C.

Methods

We reviewed the records of patients with otherwise uncontrollable glaucoma who had undergone Ahmed glaucoma valve implantation or trabeculectomy with mitomycin-C. Five eyes that underwent Ahmed valve implantation and three eyes that underwent trabeculectomy needed surgical revision of the initial surgery due to encapsulated bleb development with total loss of function. The surgically removed encapsulated blebs were analyzed macroscopically and microscopically.

Results

Removal of the encapsulated bleb was performed at a mean follow-up time of 26.6 ± 19.4 weeks in the Ahmed valve implantation group and 12.0 ± 11.4 weeks in the trabeculectomy group. The fibrotic wall of the encapsulated blebs had an overall thickness of 2.48 ± 0.42 mm in the Ahmed valve implantation group and 1.62 ± 0.37 mm in the trabeculectomy group. Macroscopically, the coconut flesh-like smooth surface was split into two layers, and the wall of the capsule was thicker in the Ahmed valve implantation group than in the trabeculectomy group. Histopathologically, the fibrotic capsule was composed of an inner fibrodegenerative layer and an outer fibrovascular layer, and there were no histopathological differences between the two groups.

Conclusions

The fibrotic capsule wall was thicker in the Ahmed valve group, but there were no differences in histological findings between the two groups.

Trabeculectomy with OloGen versus trabeculectomy for the treatment of glaucoma: a pilot study

PURPOSE

To present the preliminary results of our study comparing the outcomes of trabeculectomy with or without OloGen implant in patients requiring glaucoma surgery for uncontrolled intraocular pressure (IOP).

METHODS

Forty eyes of 40 patients were assigned randomly to undergo trabeculectomy either with OloGen implant (study group) or without implant (control group). Preoperative data included age, gender, type of glaucoma, IOP and number of preoperative glaucoma medications. Postoperative IOP, number of postoperative glaucoma medications and postoperative complications were recorded. Each patient was followed up for at least 6 months.

RESULTS

There were no significant differences between the groups in terms of age, gender, type of glaucoma, preoperative IOP and number of antiglaucoma medications. Mean IOPs for both groups were significantly lower than preoperative levels at all intervals (P < 0.05) The number of glaucoma medications used dropped from a preoperative mean of 3.5 +/- 0.7 to a 6-month postoperative mean of 0.3 +/- 0.7 (P < 0.001) in the study group and from 3.7 +/- 0.4 to 0.5 +/- 1.1 (P < 0.001) in the control group. No statistically significant differences between the two groups were observed in terms of postoperative complications.

CONCLUSION

In this pilot study it appears that trabeculectomy with OloGen does not seem to offer any significant advantages compared with trabeculectomy alone. Additionally, even though there were no statistical differences between the two groups as far as complications were concerned, one eye from the study group developed endophthalmitis 10 days after surgery and two eyes presented with positive Seidel test and flat anterior chamber and required additional suturing. Studies with larger numbers of patients and longer follow-ups are required to confirm these findings and to examine the safety and long-term outcomes of trabeculectomy with OloGen.

Tissue bioengineering for surgical bleb defects: an animal study

BACKGROUND

To assess the effectiveness of OloGen (also named iGen), a porous, bioengineered, biodegradable, collagen-glycoaminoglycan matrix implant, in preventing poor bleb formation and early failure after trabeculectomy in eyes with a surgical wound defect.

METHODS

The right eyes of 30 female New Zealand albino rabbits underwent trabeculectomy with OloGen implanted subconjunctivally on top of the scleral flap, while six right eyes received trabeculectomy without the implant to serve as a control group. A 1-2 mm diameter circular conjunctival defect was created in all eyes. Six rabbits in the group receiving the implant were sacrificed on days 3, 5, 7, 21, and 28. Rabbits in the control group were sacrificed on day 28. Perkins applanation tonometry, Seidel test and measurement of both the extent of the conjunctival defect and the anterior chamber depth were performed. Enucleated eyes were fixed in 4% formaldehyde and stained with hematoxylin and eosin (H&E) for general histological observation, and with Sirius and Fast-green stains to assess collagen deposition and cell migration.

RESULTS

Seidel tests were negative for all operated and control eyes. No flat anterior chamber occurred in either group. With the exception of days 5 and 7, post-operative mean IOP difference is significant in both groups, (P>0.05 for day 5, 7 and P<0.05 for day 3, 14, 21 and 28). In the implant group, the mean IOP was reduced by between 42% and 35% at days 14, 21, and 28, whereas the mean IOP in the control group was reduced by between only 12% and 2%. In the implant group, histology showed randomized collagen deposition and microcyst formation in the bleb after the matrix had degraded completely at day 28. In the control group, histology showed dense collagen deposition subconjunctivally at day 28.

CONCLUSIONS

OloGen successfully serves as a 3-dimensional scaffold for cell migration and proliferation, and can prevent failure by maintaining the size of the bleb in the presence of a large wound defect. It might also be successful at repairing postoperative bleb leaks.

Que faire quand la chirurgie marche mal ?

The treatment for congenital glaucoma is based on surgery, initially nonpenetrating and then penetrating. To start with, a simple trabeculectomy can be augmented by a deep sclerectomy, concentrated Mitomycin C application and iridencleisis. This surgical alternative starts with an "L" shaped conjunctival flap, followed by a superficial scleral flap, then by a deep scleral flap in which bed, Mitomycin C is applied. A trabeculectomy is then performed in the deep sclerectomy. The iris is prolapsed followed by a horseshoe iridotomy in order to suture it in the deep sclerectomy. The scleral flap is tightly sutured and the anterior chamber is filled with viscelastic material. The postoperative treatment consists of topical steroids until the IOP reaches 14mmHg; by then NSAIDs are used for several weeks. If needed, a beta-blocker or acetazolamide can be used during the hypertensive period.

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.

A novel technique of ab interno glaucoma surgery: follow-up results after 24 months

PURPOSE

It was the aim of this study to investigate the efficacy, longevity, and safety of a new ab interno intervention for the treatment of primary open-angle glaucoma (POAG).

METHODS

The previously described method of radiofrequency-mediated "sclerothalamotomy ab interno" was applied in 53 eyes of consecutive patients with POAG between April 2002 and July 2002. Average preoperative intraocular pressure (IOP) was 25.6+/-2.3 mmHg (range 18-48 mmHg). Sclerothalamotomies were carried out with a custom-made high-frequency dissection 19 G probe (tip 0.3 x 1 mm) applying bipolar current with a frequency of 500 kHz (tip temperature 130 degrees C).

RESULTS

After a follow-up period of 24 months, the average IOP was 15.0+/-1.6 mmHg (range 11-20 mmHg) (p<0.005). The average number of topical agents was 2.6+/-1.0 (range 1-5) preoperatively. Twenty-four months after surgery such agents were used in only five (9.6%) eyes and the average was 0.21+/-0.53 (range 0-2). Transient IOP elevation was observed in 12 of 53 eyes (22.6%) postoperatively. In all cases elevated IOP could efficiently be controlled with topical medication. In general, IOP dropped continuously over the course of the 6 months following surgery and then remained constant.

CONCLUSIONS

This study indicates that sclerothalamotomy ab interno is a safe and efficient surgical method for the treatment of POAG. Long-term results clearly demonstrate the longevity of IOP reduction.

A randomised, prospective study comparing trabeculectomy with viscocanalostomy with adjunctive antimetabolite usage for the management of open angle glaucoma uncontrolled by medical therapy

AIMS

To compare trabeculectomy with viscocanalostomy augmented with adjunctive antimetabolite use for the control of intraocular pressure (IOP) in open angle glaucoma (OAG).

METHODS

45 patients (50 eyes) with uncontrolled OAG were randomised to either trabeculectomy (25 eyes) or a viscocanalostomy technique (25 eyes). Preoperatively, all eyes were graded in terms of risk factors for drainage failure and were given intraoperative antimetabolites (5-fluorouracil 25 mg/ml (5-FU), mitomycin C (MMC) 0.2 mg/ml and 0.4 mg/ml) according to a standard protocol.

RESULTS

There were no significant differences between the groups in age, sex, type of OAG, preoperative medications, risk factors for drainage failure, and preoperative IOP. Mean follow up was 20 months (range 3-24 months). It was 12 months or longer in all eyes, except two lost to follow up at 3 months. At 12 months, complete success (IOP<21 mm Hg without antiglaucoma medications) was seen in 91% of eyes undergoing trabeculectomy, but in only 60% of eyes undergoing viscocanalostomy (p<0.02). Similarly, at the last follow up visit (mean 20 months) complete success was seen in 68% of eyes undergoing trabeculectomy and 34% with viscocanalostomy (p<0.05). In terms of qualified success (IOP<21 mm Hg with or without glaucoma medications) and mean IOP measurements postoperatively there were no difference between the groups, although the mean number of antiglaucomatous medications required postoperatively was less with trabeculectomy (0.39) than viscocanalostomy (1.04) (p<0.05). Needling procedures were more commonly required after trabeculectomy (p<0.02). YAG goniotomy was required in three eyes (13%) after viscocanalostomy. Early transient complications such as anterior chamber shallowing and encysted blebs were more common in the trabeculectomy group (p<0.05). Late postoperative cataract formation was similar between the two groups.

CONCLUSION

In terms of complete success and number of antiglaucomatous medications required postoperatively, IOP control appears to be better with trabeculectomy. Viscocanalostomy is associated with fewer early transient postoperative complications.

Encapsulated blebs following primary standard trabeculectomy: course and treatment

PURPOSE

To investigate the incidence and course of encapsulated filtering blebs (EB) following primary standard trabeculectomy in eyes with non-complicated glaucoma.

MATERIALS AND METHODS

Records of patients who were being followed-up in Ankara Numune Hospital, 1st Eye Clinic Glaucoma Department were analyzed and 183 eyes of 183 consecutive patients who underwent primary trabeculectomy without antimetabolites were enrolled in the study.

RESULTS

Encapsulation developed in 14 (7.6%) of 183 eyes and identification of bleb encapsulation occurred at a mean follow-up time of 5.1 +/- 5.0 weeks (median = 4 weeks). Mean intraocular pressure (IOP) levels before, during, and after the encapsulated bleb phase were 14.1 +/- 3.6, 23.4 +/- 6.9, and 14.4 +/- 3.9 mm Hg respectively. All eyes responded to conservative medical treatment consisting of aqueous suppressants without digital massage, and encapsulation resolved after a mean duration of 8.3 +/- 4.6 weeks (median = 8 weeks). Patient age, gender, glaucoma diagnosis, and preoperative IOP levels were not significantly related with the occurrence of EB formation. There was no significant difference in the use of topical beta-blockers and miotics in patients that developed EB versus those who did not; however, EB developed only in eyes with prior beta-blocker therapy and no encapsulation occurred in the 16 eyes that had not received topical beta-blockers. Mean duration of follow-up was 45.3 +/- 30.7 months (12 to 127 months) in the group without encapsulation and 44.6 +/- 22.7 months (18 to 84 months) in the EB group. Overall success rates of trabeculectomies in eyes with and without EB were not significantly different (100% and 91.7%, respectively). Complete surgical success, however, without antiglaucomatous medications at the last visit was significantly lower in eyes with prior encapsulation (35.7% with EB, 63.9% without EB) (P = 0.014).

CONCLUSION

Filtering bleb encapsulation following primary trabeculectomy responds well to conservative medical IOP-lowering therapy in eyes with glaucoma associated with elevated IOP.

The effect of trabeculectomy on the intraocular pressure of the unoperated fellow eye

PURPOSE

To investigate the intraocular pressure (IOP) changes in the unoperated fellow eye in patients who underwent trabeculectomy.

MATERIALS AND METHODS

IOP changes in the unoperated fellow eyes of 107 patients who underwent trabeculectomy in 1 eye for high-tension glaucoma (48 primary open-angle glaucoma, 43 pseudoexfoliative glaucoma, and 16 narrow-angle glaucoma) were evaluated during the early postoperative period. All IOP measurements were recorded during the postoperative first 3 months and compared with preoperative values.

RESULTS

Mean preoperative IOP levels were 37.0 +/- 10.0 mm Hg in the operated eyes and 15.1 +/- 3.1 mm Hg in the fellow eyes. Mean IOPs in the unoperated eyes on the postoperative first-day, first- and second-week, and first- and third-month visits (17.1 +/- 5.7, 17.5 +/- 5.1, 18.5 +/- 5.4, 18.6 +/- 5.1, and 19.0 +/- 5.9 mm Hg, respectively) were significantly different compared with the preoperative levels for each period of time (P < 0.01). Eight fellow eyes underwent operations for uncontrolled glaucoma before month 3. Among the remaining 99 eyes, higher postoperative IOP values were measured in 33 (33%) eyes at all postoperative visits compared with the preoperative IOP levels. A consistent IOP rise equal to or higher than 5 mm Hg was detected in 12 eyes (12%) and a consistent IOP elevation of 30% or more was found in 14 eyes (14%) during the postoperative first 3 months. Contralateral IOP elevation was not correlated with patient age, type of glaucoma, or preoperative antiglaucomatous medications prescribed to the operated or fellow eyes.

CONCLUSION

After filtration surgery, IOP of the unoperated fellow eye should also be monitored closely in order not to overlook a possible insidious rise, especially in glaucomatous eyes that were previously under good medical control.

A randomised, prospective study comparing trabeculectomy augmented with antimetabolites with a viscocanalostomy technique for the management of open angle glaucoma uncontrolled by medical therapy

AIMS

To compare trabeculectomy with viscocanalostomy for the control of intraocular pressure (IOP) in open angle glaucoma (OAG) uncontrolled by medical therapy.

METHODS

48 patients (50 eyes) with uncontrolled OAG were randomised to either trabeculectomy (25 eyes) or a viscocanalostomy technique (25 eyes). Preoperatively, eyes were graded in terms of risk factors for drainage failure. Those undergoing trabeculectomy were given intraoperative antimetabolites (5-fluorouracil 25 mg/ml (5-FU), mitomycin C (MMC) 0.2 mg/ml and 0.4 mg/ml) according to a standard protocol. Antimetabolites were not used intraoperatively in eyes undergoing viscocanalostomy, but they were randomised to the use of viscoelastic (Healonid GV) for intraoperative intracanalicular injection.

RESULTS

There were no significant differences between the groups in age, sex, type of OAG, preoperative medications, risk factors for drainage failure, and preoperative IOP. Mean follow up was 19 months (range 6-24 months). It was 12 months or longer in all eyes, except one lost to follow up at 6 months. At 12 months, complete success (IOP <21 mm Hg without antiglaucoma medications) was seen in all eyes undergoing trabeculectomy (100%), but in only 64% of eyes undergoing viscocanalostomy (p<0.001). The mean IOP was lower at 12 months (p<0.001) with trabeculectomy and the number of eyes with IOPs of 15 mm Hg or less was greater (p<0.05). The mean IOP at 12 months was lower in eyes that had undergone viscocanalostomy using intraoperative intracanalicular Healonid GV injection compared to those where only balanced saline solution had been used (p<0.01). However, in terms of complete success there was no difference between the viscocanalostomy groups (p<0.1). With the exception of measurements at 1 week, visual recovery (logMAR acuity) was similar and laser flare and cell values showed little differences between the groups. Corneal topography and keratometry at 12 months were little different from preoperative values. Postoperative interventions (subconjunctival 5-FU and needling procedures) were similar between the groups. Transient complications such as early bleb leak and hyphaema were more common in the trabeculectomy group (p<0.05). Postoperative cataract formation was more common after trabeculectomy (p<0.05).

CONCLUSIONS

IOP control appears to be better with trabeculectomy. Viscocanalostomy is associated with fewer postoperative complications, although significant complications permanently impairing vision did not occur with either technique.

The National Survey of Trabeculectomy. III. Early and late complications

PURPOSE

There is a considerable body of literature relating to trabeculectomy, however there are no data representative of the national experience of trabeculectomy in the United Kingdom (UK). The Department of Health funded a national survey of trabeculectomy to establish current practice patterns and the outcome of trabeculectomy in the National Health Service (NHS). In this paper we present the reported complications of first-time trabeculectomy from a nationally representative cohort of patients with chronic open angle glaucoma.

METHODS

Cross-sectional study of consultant ophthalmologists performing trabeculectomy in the NHS. Participants recruited their four most recent consecutive first-time trabeculectomy cases with chronic open angle glaucoma according to study eligibility criteria and data were collected by self-administered questionnaire.

FOLLOW-UP

one year post-trabeculectomy.

MAIN OUTCOME MEASURES

occurrence of early and late complications.

RESULTS

Clinical outcome data were available for 1240 (85.3%) of cases. Early complications were reported in 578 (46.6%) cases and late complications in 512 (42.3%) cases. Some cases had more than one complication. The most frequent early complications were hyphaema (n = 304, 24.6%), shallow anterior chamber (n = 296, 23.9%), hypotony (n = 296, 24.3%), wound leak (n = 216, 17.8%) and choroidal detachment (n = 175, 14.1%). The most frequent late complications were cataract (n = 251, 20.2%), visual loss (n = 230, 18.8%) and encapsulated bleb (n = 42, 3.4%). The occurrence of most complications was not associated with a consultant's specialist interest, level of activity, type of hospital or region. Encapsulated bleb was reported more frequently in a university hospital setting.

CONCLUSIONS

The complication rates reported in this paper represent the national experience of first-time trabeculectomy for open angle glaucoma in the UK. These are similar to previous published studies and highlight in particular, the impact of trabeculectomy on visual acuity in the first year following surgery. This survey provides valid and clinically relevant data on the complications of trabeculectomy for the production of guidelines and standards for audit at regional, local and individual level.

Long-term effect of phacoemulsification on intraocular pressure after trabeculectomy

PURPOSE

To evaluate the effect of temporal clear corneal phacoemulsification on intraocular pressure (IOP) in eyes that have had trabeculectomy.

SETTING

Department of Ophthalmology, University of Vienna, Vienna, Austria.

METHODS

This retrospective study evaluated the IOP in 48 eyes (35 patients) that had temporal clear corneal phacoemulsification after trabeculectomy. The mean interval between trabeculectomy and phacoemulsification was 27 months +/- 21 (SD) and the mean follow-up after phacoemulsification, 23 +/- 12 months. Intraocular pressure and antiglaucoma therapy before cataract surgery and at the end of follow-up were evaluated. For statistical analysis, the paired t test, Wilcoxon test, and chi-square test were used.

RESULTS

Thirty-five eyes (73%) preoperatively and 25 eyes (52%) postoperatively were controlled (IOP < 22 mm Hg) without antiglaucoma therapy. The difference was statistically significant (P =.04, chi-square test). At the end of follow-up, the increase in mean IOP (1.6 mm Hg) and in mean number of antiglaucoma medications (0.4) was statistically significant (P =.002 and P =.05, respectively).

CONCLUSIONS

Temporal clear corneal phacoemulsification after trabeculectomy was followed by a slight but statistically significant increase in IOP and the need for antiglaucoma medication after 2 years. However, the impairment in IOP control is comparable to that in the natural course of trabeculectomy.

Lens fluorophotometry after trabeculectomy in primary open-angle glaucoma

OBJECTIVE

To evaluate the loss of lens transparency incurred by patients undergoing trabeculectomy.

DESIGN

A prospective cohort study.

PARTICIPANTS AND CONTROLS

Data corresponding to 33 eyes of 33 consecutive patients with primary open-angle glaucoma (POAG) subjected to trabeculectomy (group 1) were compared with those corresponding to 12 eyes of 12 patients with POAG receiving topical antiglaucomatous treatment (group 2).

INTERVENTION

Lens fluorophotometry was performed on the group 1 patients before and 12 months after surgery. In group 2, fluorophotometry was conducted at the onset of the study and at 12 months of follow-up.

MAIN OUTCOME MEASURES

Starting and final lens autofluorescence and transmittance values corresponding to each subject group were compared.

RESULTS

In group 1, starting and final autofluorescence was 556.3 +/- 184.3 and 691.1 +/- 179.3 Eq ng/ml, and starting and final transmittance was 0.78 +/- 0.11 and 0.67 +/- 0.14, respectively. Respective values for group 2 were 574.3 +/- 94.8 and 595.2 +/- 107.0 Eq ng/ml and 0.72 +/- 0.17 and 0.71 +/- 0.16. The mean change between final and initial autofluorescence was statistically different between groups (134.7 +/- 123.7, group 1, 20.9 +/- 25.1 Eq ng/ml, group 2; P < 0.001). Similarly, a significant difference (P < 0.001) in transmittance change was observed between the surgery and control groups (-0.11 +/- 0.072, group 1; 0.02 +/- 0.008, group 2)

CONCLUSIONS

It was demonstrated by lens fluorophotometry that trabeculectomy in POAG leads to a loss in lens transparency.

The National Survey of Trabeculectomy. II. Variations in operative technique and outcome

PURPOSE

There is a considerable body of literature relating to trabeculectomy; however, there are no data representative of the national experience of trabeculectomy in the United Kingdom (UK). The Department of Health funded a national survey of trabeculectomy to establish current practice patterns and the outcome of trabeculectomy in the National Health Service (NHS). In this paper we report variations in surgical technique and the national success rate of trabeculectomy.

METHODS

A cross-sectional survey was carried out of consultant ophthalmologists performing trabeculectomy in the NHS. Participants recruited their four most recent consecutive first-time trabeculectomy cases according to study eligibility criteria and data were collected by self-administered questionnaire.

FOLLOW-UP

1 year post-trabeculectomy. Main outcome measure of success: final intraocular pressure (IOP) less than two-thirds the pre-operative IOP. Secondary outcome measures of success: final IOP less than 21 mmHg and visual field stability. Success was further defined as unqualified (excluding patients on anti-glaucoma medications at final follow-up) or qualified (including patients on anti-glaucoma medications at final follow-up). The relationship between variables characterising consultants' practice and main outcome measure was examined by chi-square test.

RESULTS

Clinical outcome data were available for 1240 (85.3%) cases. There were wide variations in operative technique. The mean post-operative IOP was 14.4 mmHg (95% CI 14.2-14.7), which is a mean reduction of 11.8 mmHg (95% CI 11.4-12.2). An unqualified success, in terms of the main outcome measure, was achieved in 66.6% of patients and a qualified success in 71.0% of cases. An unqualified success, in terms of a final IOP less than 21 mmHg, was achieved in 84.0% of cases and a qualified success in 92.0%. Visual fields were stable in 84.2%. Outcome was not related to consultants' specialist interest, level of activity, type of hospital or region.

CONCLUSIONS

The success rates reported in this paper represent the national experience of first-time trabeculectomy for open angle glaucoma in the UK. The national success rate at 1 year compares favourably with many studies in the literature. This survey provides valid and clinically relevant measures of success for the production of guidelines and standards for audit at regional, local and individual level and a baseline for the comparison of new therapies.

Non-enhanced trabeculectomy by non-glaucoma specialists: are results related to risk factors for failure?

PURPOSE

To determine the 1 year success rate of non-enhanced trabeculectomy under the care of non-glaucoma specialists and the effects of risk factors on the surgical outcome as measured by intraocular pressure (IOP) control.

METHODS

A retrospective study of 167 patients undergoing trabeculectomy was performed. One hundred and four cases were performed in a teaching hospital and 63 in a district general hospital (DGH). Non-glaucoma specialists performed all the operations, enhanced trabeculectomy with antimetabolites being excluded. Information was recorded from a retrospective review of case notes, and post-operative IOPs at 12 months follow-up were analysed. Risk factors for failure were defined as: (1) age less than 40 years old, (2) black race, (3) diabetes mellitus, (4) miotic therapy > or = 18 months, (5) sympathomimetic therapy > or = 6 months, (6) pseudophakia or aphakia, (7) previous failed filtration procedure, (8) argon laser trabeculoplasty, (9) previous ocular surgery and (10) high-risk glaucoma (angle recession glaucoma, uveitic glaucoma and neovascular glaucoma). A success was defined to be a post-operative IOP at 1 year of less than 21 mmHg and at least 20% less than the presenting IOP on no medication.

RESULTS

The overall success rate was 139 of 167 (83.2%). Eighty-seven of 104 eyes (83.7%) were classified as a success in the teaching hospital group and 52 of 63 (82.5%) were classified as a success in the DGH group. There was no significant difference in the number of risk factors between the success and failure groups. Eyes with two or more risk factors had significantly higher IOPs at 1 year when compared with eyes with 0 or 1 risk factor (mean +/- SD: 17.4 +/- 6.34 mmHg vs 14.2 +/- 5.0 mmHg, p = 0.022). When only 'successful eyes' were analysed, those with two or more risk factors still had significantly higher IOPs at 1 year (mean +/- SD: 15.0 +/- 3.0 mmHg vs 12.8 +/- 3.9 mmHg, p = 0.046). There were significantly fewer eyes in the two or more risk factor group with IOPs < 16 mmHg at 1 year (26.1% vs 60.4%, p = 0.021).

CONCLUSIONS

Eyes at relatively low risk for failure operated upon by non-glaucoma specialists appeared to have success rates similar to previously published series. Eyes with two or more risk factors for failure have higher IOPs at 1 year in non-enchanced trabeculectomy. Adjunctive anti-scarring agents may be considered for these patients when filtration surgery is scheduled.

Trabeculectomy survival with and without intra-operative 5-fluorouracil application in an Asian population

PURPOSE

To define and compare the trabeculectomy survival with regard to intra-ocular pressure (IOP) control without further surgery or anti-glaucoma medication n an Asian population.

METHODS

A retrospective review of two consecutive groups of patients who had trabeculectomy surgery in a university eye department setting. The first group of patients (group A) did not receive any adjunctive 5-fluorouracil (5-FU), while the second group (group B) had intra-operative sponge application of 5-FU. Only the first trabeculectomy of patients who had bilateral trabeculectomy and the first trabeculectomy performed in patients who had repeated surgery was analysed. Combined procedures were excluded. Survival analysis was performed using the Kaplan-Meier product limit method.

RESULTS

Eighty-nine patients (51 in group A and 38 in group B) were studied, with a mean follow up of 37.5 and 27.0 months, respectively (P = 0.014). There were no statistical differences in age, gender, mean pretreatment IOP, pre-operative medication, proportion of patients with previous ocular surgery, or proportion of primary compared with secondary glaucoma between the two groups. The probability of trabeculectomy survival (IOP < 22 mmHg without additional medication/surgery) at 12 and 36 months was 54.3 and 36.4%, respectively, in group A and 75.8 and 65.8%, respectively, in group B. The differences in survival were significant (P = 0.006, log rank test).

CONCLUSIONS

Our experience with trabeculectomy survival in the Asian population showed poorer success when compared with Caucasian populations reported by other investigators. The survival of trabeculectomy surgery was improved significantly with intra-operative 5-FU. There may be justification for advocating a more liberal use of intra-operative 5-FU in such a population.

Trabeculectomy function after cataract extraction

OBJECTIVE

To examine the effect of cataract extraction (CE) after trabeculectomy on intraocular pressure (IOP) control.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

A total of 115 consecutive patients who underwent extracapsular CE (N = 58) or phacoemulsification (N = 57) with intraocular lens (IOL) placement after trabeculectomy were studied.

INTERVENTION

Cataract extraction with IOL after trabeculectomy was performed.

MAIN OUTCOME MEASURES

Preoperative, intraoperative, and postoperative factors were evaluated for association with loss of IOP control requiring additional medications, bleb needling, or further glaucoma surgery, using Kaplan-Meier survival analysis and Cox multivariate proportional hazards survival regression.

RESULTS

After mean postoperative follow-up of 21.1 +/- 14.3 months, additional glaucoma medication or needling of the filtering bleb to maintain IOP control was required in 35 eyes (30.4%) and was significantly associated with intraoperative iris manipulation and early postoperative peak IOP greater than 25 mmHg. Additional glaucoma surgery was eventually required in 11 eyes (9.6%) and was significantly associated with age of 50 years or younger, preoperative IOP greater than 10 mmHg, and early postoperative peak IOP greater than 25 mmHg. The cumulative proportion of patients who did not require reoperation for glaucoma was 93% and 90% at 1 and 2 years, respectively. The mean IOP at last visit had increased 1.6 mmHg above the pre-CE level and did not vary significantly after the first postoperative month. The median interval from CE to the addition of glaucoma medication or bleb needling was 1.6 months (within 3 months in 20 of 33 eyes) and that from nonsurgical intervention to further glaucoma surgery was 3.6 months (before the 7th postoperative month in 6 of 11 eyes). Of 19 eyes with hypotony (IOP < or = 6 mmHg) before CE, 11 eyes remained hypotonous after CE despite an increase in the mean IOP from 4.6 to 7.5 mmHg.

CONCLUSIONS

When CE is performed after trabeculectomy, age of 50 years or younger, preoperative IOP greater than 10 mmHg, intraoperative iris manipulation, and early postoperative IOP greater than 25 mmHg are associated with worsened postoperative IOP control. Most bleb failures occur soon after CE. Resolution of pre-existing hypotony after CE is unpredictable.

The effect of heparin-coated intraocular lenses on intraocular pressure following combined trabeculectomy and cataract surgery

PURPOSE

To review the effects on intraocular pressure control of the use of standard and heparin-coated intraocular lenses (IOLs) following combined cataract and glaucoma surgery after a minimum period of 2 years.

METHODS

Case note review of all patients with glaucoma who required cataract extraction combined with trabeculectomy and who were randomized to either of the two IOL types. The number of ocular hypotensive medications and the intraocular pressures were recorded pre-operatively and at 3, 6, 18 and 24 months following surgery.

RESULTS

The two groups (9 receiving standard IOLs and 10 heparin-coated IOLs) were comparable for age, sex and follow-up, as were the pre-operative intraocular pressures and number of treatments. Post-operatively, all patients achieved an intraocular pressure < 21 mmHg at the final visit, with only one patient in each group requiring topical medication, but the standard lens group had a higher intraocular pressure at 2 years (p<0.05). The magnitude of the fall from the pre-operative values was greater in the heparin-coated lens group at 2 years after surgery (p<0.02). The presence of a visible drainage bleb occurred equally frequently in the two groups.

CONCLUSIONS

Use of a heparin-coated IOL does not adversely affect the intraocular pressure control following combined cataract and drainage surgery. The greater fall in intraocular pressure at 2 years in those receiving a heparin-coated IOL may have occurred by chance.

Long-term follow-up of initially successful trabeculectomy

OBJECTIVE

The purpose was to study the long-term outcomes of primary trabeculectomies that were successful at 1 year.

DESIGN

A retrospective study of patients with various types of glaucoma who had trabeculectomies that were successful at 1 year and who had a follow-up of at least 10 years.

PARTICIPANTS

There were 40 patients (40 eyes) who had primary trabeculectomies that were successful at 1 year and who had a follow-up range of 10 to 21 years.

INTERVENTION

Control of intraocular pressure (IOP) and disease progression was evaluated at 5, 10, and 15 years and at the last obtainable follow-up.

MAIN OUTCOME MEASURES

Successful control of IOP was defined as IOP less than 21 mmHg or a reduction of 33% if preoperative IOP was less than 21 mmHg. Successful control of disease progression was defined as stable cup-disc ratios determined by examination, or color photographs or both, as well as stable visual fields.

RESULTS

If an eye was considered successful by IOP at 1 year, the probability of successful control of IOP was 82% at 5 years and 67% at 10 and 15 years. If an eye was considered successful by IOP at 1 year, the probability of successful control of disease progression at 5 years was 77%, at 10 years 61%, and at 15 years 48%. If an eye did not require further glaucoma surgery at 1 year, the probability that it still would not need further surgery at 5 years was 90%, at 10 years 75%, and at 15 years 67%. Forty percent of eyes had cataract extraction by the time of last follow-up examination.

CONCLUSIONS

Loss of IOP control and progression of glaucomatous damage occurs over time despite initial success at 1 year.

Subconjunctival retention of C3F8 gas increased the success rates of trabeculectomy in young people

In this study, the effect of subconjunctival retention of perfluoropropane (C3F8) gas on trabeculectomy was evaluated to determine if this maneuver would increase the success rate of the surgery. Thirty-two patients (under 35 years old) with a diagnosis of primary open-angle glaucoma or steroid-induced glaucoma were randomized into two groups to receive trabeculectomy: Group A (trabeculectomy alone, 16 eyes) and Group B (trabeculectomy with subconjunctival retention of 0.5 mL pure C3F8 gas, 16 eyes). The results showed that the typical appearance of a subconjunctivally retained C3F8 filtering bleb is highly distended in the first two weeks after surgery, followed by flattening and diffusing gradually. The average retention time of C3F8 gas within the subconjunctival space is 28 +/- 6 days. A higher success rate was noted in Group B than in Group A (94% versus 50%, p = 0.016) at a mean follow-up time of 12 months. However, there were no differences in complication rates and results of final visual acuity between the two groups (both groups had two patients lose more than two lines of vision, p = 1.0). Our study suggests that subconjunctival retention of C3F8 gas increases the success rate of trabeculectomy in young people in the intermediate-term (12 months) follow-up period.