Mitomycin C versus 5-fluorouracil in high-risk glaucoma filtering surgery. Extended follow-up

Efficacy and safety of trabeculectomy with mitomycin C for childhood glaucoma: a study of results with long-term follow-up

OBJECTIVE

To evaluate the safety and effectiveness of trabeculectomy with mitomycin C in the management of childhood glaucoma.

INTRODUCTION

The use of antifibrotic agents enhances the success of trabeculectomy performed in both adults and children.

METHODS

A retrospective chart review (1991-2001) of 114 patients (114 eyes) from 0-14 years of age with congenital or developmental glaucoma. These patients underwent trabeculectomy with mitomycin but had not been previously treated with any antifibrotic agent.

RESULTS

The mean patient age was 57.36+/-51.14 months (range: 0.5-168 months). Treatment was considered successful in 63 eyes (55.26%), with a mean intraocular pressure of 12.11+/-3.98 mmHg. For patients categorized as successfully treated, the mean follow-up time was 61.16+/-26.13 months (range 12-113 months). A post-surgical intraocular pressure of <16 was observed in 47 eyes. The life-table success rates for intraocular pressure control at 24, 36, 48, and 60 months were 90.2%, 78.7%, 60.7% and 50.8%, respectively. The cumulative probability of failure was 40.8% at 12 months. Following surgery, endophthalmitis appeared in eight eyes (4.88%) after an average 36.96 months (range: 1.7-106 months). Other complications included expulsive hemorrhage, flat anterior chamber and bleb leak.

DISCUSSION

It has been reported in pediatric patients that trabeculectomy without adjunctive antimetabolites achieves a successful outcome in 30% to 50% of cases. In our study, treatment was considered successful in 63 eyes (55.26%) within 61.16+/-26.13 months of follow-up.

CONCLUSIONS

Trabeculectomy with mitomycin is safe and effective for short-term or long-term treatment of congenital or developmental glaucoma. The frequency of bleb-related endophthalmitis was no higher in these patients than that described in adults.

Repeat administration of proteins to the eye with a single intraocular injection of an adenovirus vector

Delivery of therapeutic proteins, such as antiangiogenic proteins, to the eye is a demonstrated method for the control of age-related macular degeneration (AMD). However, one of the key limitations is the requirement for frequent and repeated intraocular injections. In this article, we demonstrate that repeated protein production in the eye can be stimulated from the cytomegalovirus (CMV) promoter without repeat intraocular injections using a small molecule, all-trans retinoic acid (ATRA). ATRA by systemic delivery can stimulate protein production multiple times in the eye. Administration of ATRA resulted in stimulation of gene expression to relevant levels that block abnormal blood vessel growth in an experimental animal model for AMD. These data support the principles of this technological discovery to therapeutic applications for chronic ocular diseases.

Pars plana vitrectomy and panretinal photocoagulation combined with trabeculectomy for successful treatment of neovascular glaucoma

BACKGROUND

Treatment of neovascular glaucoma (NVG) must be focused on the reduction of intraocular pressure (IOP) and prompt application of pan retinal photocoagulation (PRP). A combination of complete PRP during vitrectomy with trabeculectomy should theoretically be a better method to lower the IOP rapidly in eyes with NVG. The purpose of our study is to assess the efficacy of combining pars plana vitrectomy and PRP with trabeculectomy assisted by mitomycin C (MMC) on NVG eyes secondary to diabetic retinopathy.

METHODS

Twenty-five eyes with NVG associated with diabetic retinopathy had pars plana vitrectomy, followed by PRP and trabeculectomy with MMC. The eyes were divided into two groups: nine eyes with vitreous hemorrhage, fibrovascular membrane and/ or retinal detachment were placed in the Proliferation group; and 16 eyes without vitreous hemorrhage, fibrovascular membrane, or retinal detachment were placed in the PC (photocoagulation) group. These eyes had vitrectomy performed so that PRP could be safely performed from ora to ora. The surgical outcome in the two groups was assessed by Kaplan-Meier survival analysis. The criteria for success were a postoperative intraocular pressure (IOP) < or =21 mmHg and a preservation of light perception.

RESULTS

In the Proliferation group, Kaplan-Meier life-table analysis showed that the success rate was 55.6% after 1 year and 18.5% after 2 years. The success rate in the PC group was 81.2% from 1 to 3 years after surgery. The surgical outcome was significantly better in the PC group than in the Proliferation group (P=0.009). In the Proliferation group, four eyes had preoperative vitreous hemorrhage, three eyes had a fibrovascular membrane, and two eyes had a retinal detachment. Three of four eyes with vitreous hemorrhage achieved good IOP control. On the other hand, the IOP of all eyes with retinal detachment and fibrovascular membrane were not lowered significantly.

CONCLUSIONS

Complete PRP combined with trabeculectomy with MMC can effectively reduce the elevated IOP in eyes with NVG. However, this combined treatment is not effective in eyes with proliferative membranes and retinal detachments.

Uses and complications of mitomycin C in ophthalmology

Mitomycin C is a chemotherapeutic agent that acts by inhibiting DNA synthesis. Its use and application in ophthalmology has been increasing in recent years because of its modulatory effects on wound healing. Current applications include pterygium surgery, glaucoma surgery, corneal refractive surgery, cicatricial eye disease, conjunctival neoplasia and allergic eye disease. Although it has been used successfully in these conditions, it has also been associated with significant complications. This article reviews the current trends and uses of mitomycin C in the eye and its reported complications.

The Clinical Applications of Fluorouracil in Ophthalmic Practice

Fluorouracil (5-fluorouracil, 5-FU) is a pyrimidine analogue that was originally known for its widespread use as an anticancer drug. The ability of 5-FU to reduce fibroblastic proliferation and subsequent scarring has made it an important adjunct in ocular and periorbital surgeries. It is used in primary glaucoma filtering surgeries and in reviving failing filtering blebs, in dacryocystorhinostomy, pterygium surgery, and in vitreoretinal surgery to prevent proliferative vitreoretinopathy. In addition, 5-FU is also gaining recognition in the treatment and surgical management of ocular surface malignancies like ocular surface squamous neoplasia; however, the specific action of the drug on highly proliferating cells limits its use in primary acquired melanosis of the conjunctiva. When applied topically, this drug has a low rate of sight-threatening adverse effects, is inexpensive, and is easy to administer, making it an important tool in enhancing the success rate in ophthalmic surgery and in reducing the recurrence of ocular surface neoplasia.

Trabeculectomy with mitomycin C for treatment of neovascular glaucoma in diabetic patients

BACKGROUND

To assess the efficacy and to determine the risk factors of trabeculectomy with mitomycin C (MMC) in eyes with neovascular glaucoma (NVG) secondary to diabetic retinopathy.

METHODS

Kaplan-Meier survival analysis of the surgical outcome was performed on 35 eyes with NVG. Age, extent of peripheral anterior synechia, surgical history (cataract, glaucoma, vitrectomy), and concurrent retinal cryotherapy were evaluated to determine factors influencing the surgical outcome. The main criterion for success was a postoperative intraocular pressure (IOP) of < or = 21 mm Hg.

RESULTS

The cumulative probability of success was 67.0% at 1 year and 61.8% after 2 to 3 years. The surgical outcome was significantly better in patients without a previous vitrectomy (p = 0.03). Extensive preoperative peripheral anterior synechia was also a risk factor for surgical failure (p = 0.013).

CONCLUSIONS

Trabeculectomy with MMC can effectively reduce the elevated IOP associated with NVG. The extent of peripheral anterior synechia and a history of vitrectomy are significant negative predictors of surgical outcome.

Subconjunctival placement of human amniotic membrane during high risk glaucoma filtration surgery

BACKGROUND AND OBJECTIVE

To determine whether subconjunctival placement of amniotic membrane improves filtration results in patients with glaucoma at high risk for surgical failure.

PATIENTS AND METHODS

Retrospective review of 17 eyes of 15 patients who had amniotic membrane applied during glaucoma surgery with or without mitomycin C or 5-fluorouracil.

RESULTS

Mean intraocular pressure decreased from 27.0 +/- 9.1 mm Hg preoperatively to 18.1 +/- 11.0 mm Hg postoperatively with a mean follow-up of 179 days. Complications included self-limited conjunctival wound dehiscence (n = 5), uveitis recurrence (n = 2), and cataract progression (n = 1).

CONCLUSIONS

The results suggest that subconjunctival placement of amniotic membrane may improve filtration outcome in high risk eyes. It will be of interest to determine whether the anti-inflammatory, anti-angiogenic, and antifibrotic properties of amniotic membrane placed subconjunctivally and under the scleral flap will improve filtration surgery outcome by a prospective, randomized study.

Rescue of failed filtering blebs with ab interno trephination

We evaluated the effectiveness of ab interno automated trephination as a technique for rescuing failed mature filtering blebs. A retrospective chart review of 40 failed blebs of 38 patients who had a posttrephination follow-up period of at least 3 months was done. With success defined as intraocular pressure (IOP) <21 mm Hg and at least a 20% reduction from baseline on the same or fewer number of pretrephination medications, 30/40 eyes (75%) fit these criteria over the entire course of follow-up. Among all 40 eyes, there was a significant reduction of IOP from pretrephination to 3 months (P<.001). The percentage of patients requiring 2 or more medications declined from 90% pretrephination to 21% at 3 months (P<.0001), and was stable thereafter. Some patients were able to eliminate all medications. Patients who did not meet the criteria of success regained successful IOP control with other modalities of management. Complications were few. We believe that ab interno trephination is an excellent option for rescuing selected failed filtering blebs.

Postoperative application of mitomycin c improves the complete success rate of primary trabeculectomy: a prospective, randomized trial

BACKGROUND

The intraoperative application of mitomycin c for primary trabeculectomy is associated with potentially sight-threatening side-effects. This study was performed to evaluate the pressure-lowering effect of postoperative application of mitomycin c for primary trabeculectomy and to evaluate the complications of this new technique.

MATERIALS AND METHODS

A randomized, prospective clinical trial with 52 consecutive patients scheduled for glaucoma surgery in one large surgical center was performed. Patients underwent routine trabeculectomy. In group 1, mitomycin c (0.05 mg/ml) was applied topically to the filtering bleb for 5 min on the 3 days after surgery (postoperative application). In group 2, no mitomycin c was applied (controls). The IOP values, visual acuity, number of antiglaucomatous medications and complications were evaluated.

RESULTS

Follow-up was evaluated up to 24 months for all patients. The mean intraocular pressure decreased from 31.1 to 15.4 mmHg in group 1 and from 24.8 to 15.6 mmHg in group 2 (P=0.79; t-test). The average number of medications decreased from 2.5 and 2.4 to 0.4 and 0.6 (P=0.53; t-test) in groups 1 and 2, respectively. No cases of hypotony maculopathy occurred. An individual decrease of more than 25% of the IOP was present in 84.6% in group 1 and in 53.8% in group 2 (P<0.017). Survival analysis for eyes with a complete surgical success revealed a better outcome of eyes in group 1 as compared to the eyes in group 2 (P<0.013; log-rank test).

CONCLUSIONS

To our knowledge, this is the first prospective, randomized clinical trial to evaluate the efficacy of postoperative mitomycin c application in primary trabeculectomy. The application of mitomycin significantly reduced the IOP while not increasing the rate of complications.

Sequential induction of angiogenic growth factors by TNF-alpha in choroidal endothelial cells

Inflammatory mediators have been proposed to play a critical role in the pathogenesis of choroidal neovascularization, a blinding complication of age-related macular degeneration. We evaluated the expression of TNF-alpha in human choroidal neovascular membranes and found that it colocalized with cells expressing VEGF, angiopoietin (Ang)-1 and Ang2. In cultured choroidal endothelial cells we found that TNF-alpha increased Ang2 mRNA (increased transcription) and protein levels prior to those of Ang1 and VEGF. The results raise the possibility that during neovascularization, TNF-alpha may modulate endothelial plasticity and survival by sequential inactivation of Tie2 followed by activation of Tie2 and VEGF receptors.

Intermediate-term comparison of trabeculectomy with intraoperative mitomycin-C between Asian American and Caucasian glaucoma patients: a case-controlled comparison

PURPOSE

Compare the efficacy and survival of trabeculectomy with intraoperative mitomycin-C (MMC) between Asian American and Caucasian patients in the same clinical setting.

METHODS

In total, 29 Asian American patients (29 eyes) with trabeculectomies were matched case to case with 29 Caucasian patients (29 eyes) retrospectively. Matching criteria included age, glaucoma subtype, and preoperative intraocular pressure (IOP), gender, surgeon, ocular history, and glaucoma medications. Criteria of success included: (1) Final IOP>5 and <22 mmHg, (2) IOP reduction>or=20%, or final IOP<or=10 mmHg, and (3) without additional glaucoma surgery, loss of light perception, or complication.

RESULTS

Mean follow-up durations of Asian American and Caucasian group were 40.11+/-22.5 months and 38.8+/-17.7 months, respectively (P=0.81). At the final visits, IOP decreased from 18.7+/-6.1 to 10.9+/-4.0 mmHg (P<0.0001) in the Asian American group, and from 19.0+/-5.5 to 11.0+/-3.8 mmHg (P<0.0001) in the Caucasian group. There were no significant differences between the two groups in IOP levels at 6 months, 1 year, and final visits. The probabilities of trabeculectomy survival (continuing to meet definition of success criteria) at 12 and 48 months were 75.9 and 56.6% in the Asian American group and 82.8 and 66.6% in the Caucasian group, respectively. (P=0.46) There were no significant differences for rates of surgical success, failure, complication, vision decrease, hypotony, and cataract development. Patients who had episodes of hypotony had a higher rate of diagnosis of low-tension glaucoma subtype (P=0.02).

CONCLUSIONS

In a case-controlled comparison of an intermediate-term follow-up of trabeculectomy with intraoperative MMC, Asian American patients have a similar efficacy and survival probability as Caucasian patients.

Ahmed valve drainage implant surgery in the management of paediatric aphakic glaucoma

BACKGROUND

Paediatric aphakic glaucoma presents months or years after cataract surgery in children and is a major long term complication. The results of surgical treatment are poor and many children require multiple and repeat procedures with poor visual outcomes.

METHODS

13 children (19 eyes) had Ahmed valve implantation surgery, nine of the children had previous procedures such as cycloablation or trabeculectomy. Mitomycin was used at surgery in some patients and valve needling with Healon GV and 5-fluorouracil in some blebs after surgery. SF(6) gas was also used at the time of surgery in most children to reform the anterior chamber.

RESULTS

12 of the children (18 eyes) achieved intraocular pressure control of 15 mm Hg or less with a valve alone or with additional medical therapy.

CONCLUSION

Ahmed valve implantation surgery alone or in combination with medical therapy is successful and safe in the management of paediatric aphakic glaucoma.

VEGF differentially regulates transcription and translation of ZO-1alpha+ and ZO-1alpha- and mediates trans-epithelial resistance in cultured endothelial and epithelial cells

Tight junctions (TJ) between retinal pigmented epithelial (RPE) and retinal endothelial cells maintain the outer and inner blood-retinal barrier, and the breakdown of these barriers is associated with retinal diseases. Vascular endothelial growth factor (VEGF) increases vascular permeability and is thought to be involved in age-related maculopathy. However, to date, little is known about the effect of VEGF on RPE cell junctions. We have investigated the effect of VEGF on TJ formation by examining two essential proteins, ZO-1alpha(+) and ZO-1alpha(-). Cultured vascular endothelial cells in the presence of 5 ng/ml VEGF significantly down-regulate ZO-1alpha(+) and ZO-1alpha(-) transcripts and proteins with significant loss of their trans-epithelial resistance (TER). Immunoconfocal analysis with an anti-ZO-1 antibody has confirmed the relocation of ZO-1 protein from membrane to cytoplasm. By contrast, in the presence of 5 ng/ml VEGF, cultured RPE cells (ARPE19 and RPE51) significantly up-regulate ZO-1alpha(+) and ZO-1alpha(-) transcripts and proteins resulting in a significant increase in their TER. Subsequent immunoconfocal analysis has demonstrated increased ZO-1 membrane assembly in VEGF-treated RPE cells. Thus, VEGF has a dual capability with respect to the regulation of the expression of some TJ proteins at the transcriptional and post-translational levels depending on cell type.

Combined clear corneal phacoemulsification and ab interno trabeculectomy: Three-year case series

PURPOSE

To evaluate the efficacy and safety of a novel surgical approach, ab interno trabeculectomy, in a combined procedure (clear corneal phacoemulsification + ab interno trabeculectomy) for the management of concurrent cataract and glaucoma with prognostic factors for filtration failure.

SETTING

Department of Ophthalmology, Palmanova Hospital, Udine, Italy.

METHODS

A prospective noncomparative case series of 11 eyes of 11 consecutive cataract patients with medically uncontrolled primary open-angle glaucoma or pseudoexfoliation glaucoma was performed. Each patient had phacoemulsification + intraocular lens implantation + ab interno trabeculectomy, which consisted of a gonioscopically controlled ab interno removal of a quadrant (3 clock hours) of the trabecular meshwork. The main outcome measures were intraocular pressure (IOP), the number of antiglaucomatous medications used, and complications.

RESULTS

Ten patients completed a 3-year follow-up. One patient had further surgery because of poor IOP control; in this case, the last valid observation was carried forward for IOP calculation. Mean preoperative IOP and IOPs measured 1, 3, 6, 12, 24, and 36 months after surgery were 25.0, 15.8, 15.4, 15.4, 15.2, 15.0, and 15.3 (-38.56%) mm Hg respectively. The number of medications averaged 2.4 before surgery and dropped to 0.8 at the end of follow-up. No major complications occurred during the follow-up period.

CONCLUSIONS

The new surgical procedure combining phacoemulsification with ab interno trabeculectomy can induce a clinically relevant decrease in IOP in eyes with cataract and glaucoma with poor prognosis for filtering surgery. However, a randomized controlled clinical trial with a more extended follow-up and a larger series of patients is needed to ascertain the actual effectiveness and safety of this procedure.

Bullous keratopathy as a complication of trabeculectomy with mitomycin C

BACKGROUND

The routine use of mitomycin C to enhance glaucomatous filtering surgery has found wide acceptance. Complications of the application of mitomycin C have been repeatedly noticed. We now report a previously undescribed complication showing a toxic effect of mitomycin C to the corneal endothelium.

METHODS

Patients underwent routine trabeculectomy with mitomycin C. Following surgery, the eyes were examined by biomicroscopy and specular microscopy of the corneal endothelium.

RESULTS

In two cases, we observed a partial decompensation of the corneal endothelium resulting in a well-demarcated clear zone of the cornea and a second zone with thickening of the cornea and a bullous keratopathy adjacent to the filtering bleb. The specular microscopy showed marked irregularities of the endothelial cells and areas of necrosis in those parts of the cornea close to the filtering bleb.

CONCLUSIONS

The two cases described here demonstrate that if the corneal endothelium is already compromised before surgery, the application of mitomycin C may have an additional toxic effect on the endothelium and may result in a partial bullous keratopathy. Surgeons should be aware of this complication.

2002 survey of the American Glaucoma Society: practice preferences for glaucoma surgery and antifibrotic use

PURPOSE

To determine the preference of members of the American Glaucoma Society for the use of antifibrotic agents (mitomycin C or 5-fluorouracil or both) and glaucoma drainage devices in ten clinical settings.

MATERIALS AND METHODS

Voluntary written survey of the American Glaucoma Society.

RESULTS

American Glaucoma Society (AGS) members continue to report preference for mitomycin C use in ten clinical settings. The percent usage for glaucoma drainage devices has increased in poor prognosis scenarios including the following: neovascular glaucoma, previous failed trabeculectomy, previous ECCE/ICCE, previous PKP, previous scleral buckling surgery, and uveitic glaucoma. However, trabeculectomy and MMC continue to be more likely employed for surgical management.

CONCLUSION

Despite the long-term complications of bleb-related infections, no statistically significant shift in preference away from MMC use or reduction in the concentration of drug delivery was observed since the 1996 survey.

Long-term results of trabeculectomy with different concentrations of mitomycin C in refractory developmental glaucoma

PURPOSE

To evaluate the long-term results of trabeculectomy with two different concentrations of mitomycin C in refractory developmental glaucoma.

PATIENTS AND METHODS

A total of 48 eyes of 37 patients with previous failure of congenital glaucoma surgery underwent mitomycin C-augmented trabeculectomy. Data were analyzed retrospectively, and patients were divided into two groups. Group 1 consisted of 18 patients (25 eyes) who underwent trabeculectomy with a 0.4 mg/mL mitomycin C solution and group 2 consisted of 19 patients (23 eyes) who underwent trabeculectomy with a 0.2 mg/mL mitomycin C solution. Pre- and postoperative intraocular pressure (IOP), best-corrected visual acuity, bleb characteristics, success rate, and complications were compared for both groups.

RESULTS

Mean time between primary surgery and mitomycin C-augmented trabeculectomy was 19.3 months (range, 11 months to 7 years). Mean preoperative IOP was 28.4 +/- 2.9 mm Hg in group 1 and 29.0 +/- 2.4 mm Hg in group 2. Final postoperative IOP was 17.0 +/- 1.6 for group 1 and 17.1 +/- 1.4 mm Hg for group 2. There were no significant differences between the groups for IOP, success rate, and complications (P > .05). The most common postoperative complication was shallow anterior chamber (11 [22.9%] of 48 eyes).

CONCLUSIONS

A 0.4 or 0.2 mg/mL mitomycin C solution for 4 minutes may be used during trabeculectomy in refractory developmental glaucoma.

Effects of matrix metalloproteinase-3 gene transfer by electroporation in glaucoma filter surgery

To develop gene therapy that can be applied to glaucoma-filtering surgery, we studied effects of transfection of matrix metalloproteinase-3 (MMP-3) cDNA into rabbit conjunctiva by electroporation (EP) on changes of intraocular pressure (IOP) and bleb formation after glaucoma filtering surgery. pTracer-CMV2 vector containing MMP-3 cDNA was transfected into rabbit conjunctiva by EP and MMP-3 expression was studied by reverse transcription (RT)-PCR, zymography and western blot analysis. Three days after the EP transfection of MMP-3 cDNA or vector alone into rabbit conjunctiva, trabeculectomy was performed at the place of transfection in the presence or absence of 0.04% mitomycin C (MMC). Then changes in IOPs and bleb formation were compared with each other. Expression of MMP-3 was detected in conjunctiva until 30 days after transfection by EP. Trabeculectomy following MMP-3 transfection caused significantly longer survival of filtering bleb and decreased levels of IOP in comparison with controls (trabeculectomy alone or trabeculectomy following vector transfection), and these levels were almost identical to those of trabeculectomy with MMC. The present study indicates that EP is effective to transfect some genes that promote the filtering bleb formation in glaucoma surgery, such as MMP-3 gene, and this may be potentially applicable to glaucoma-filtering surgery in glaucoma patients.

Update on antifibrotic use in glaucoma surgery, including use in trabeculectomy and glaucoma drainage implants and combined cataract and glaucoma surgery

PURPOSE OF REVIEW

This paper summarizes the use of antifibrotic agents adjunctive to glaucoma surgery, reviews recently published studies that address current use of these antifibrotics, and reviews new methods of wound modulation.

RECENT FINDINGS

The use of antifibrotic agents, namely, 5-fluorouracil and mitomycin C, in conjunction with glaucoma surgery has resulted in lower postoperative intraocular pressures after trabeculectomy or combined cataract and glaucoma surgery. Mixed results have been seen when these agents are used with glaucoma drainage device surgery. The use of antifibrotic agents has also created and increased complications. Therefore, methods of antifibrotic use have become more refined and modified for specific circumstances. Promising new wound modulation agents, such as CAT-152, are currently under study.

SUMMARY

Antifibrotics are potent adjuncts to glaucoma surgery, but along with their beneficial use are risks that need to be considered. While we continue to look for more efficacious agents and methods to treat glaucoma, we must continue to modify techniques with the individual patient's best interest in mind.

Trans-scleral diode laser cyclophoto-coagulation in the treatment of diabetic neovascular glaucoma

AIMS

To assess efficacy of trans-scleral diode laser cyclophotocoagulation in the treatment of diabetic neovascular glaucoma refractory to medical therapy.

METHODS

Case notes of 20 eyes of 20 patients who had the treatment were analysed. The mean follow-up after initial treatment was 22.5 months (range of 18-24).

RESULTS

Mean (SD) pretreatment intraocular pressure (IOP) for the 20 eyes was 34.4 mmHg (9.5) reducing to 18.2 mmHg (12.4) at the final index visit (P = 0.0001). The mean (SD) number of topical antiglaucoma medication was significantly lowered from 3.9 (0.3) to 1.2 (1.3). Four patients had visual acuity of 6/60 or better before the treatment. Two of them maintained the same level of vision and the other two had their vision reduced over the course of study; however, none of them deteriorated beyond 6/60. Six out of the remaining 16 patients who had vision of counting fingers or worse before treatment progressed to no perception of light at the final index visit. The mean (SD) number of treatment sessions was 1.45 (0.68). A total of 10 patients had previous pars plana vitrectomy (PPV). Patients with two or more PPVs developed hypotony (IOP </=5). There were five eyes with hypotony, one of which became phthisical.

CONCLUSION

Trans-scleral diode laser cyclophotocoagulation is a useful tool in the management of diabetic neovascular glaucoma. The current treatment regime needs to be adjusted to reflect higher risk of hypotony and phthisis in diabetic neovascular glaucoma in eyes that have had multiple pars plana vitrectomies.

Needling revision of failed filtering blebs after trabeculectomy: a retrospective study

PURPOSE

To determine the efficacy and safety of needling revision of failed filtering blebs.

METHODS

We reviewed retrospectively 26 eyes that had undergone needling revision for a failed trabeculectomy. The needling revisions were performed either with adjunctive use of Mitomycin C, 5-Fluorouracil or without antimetabolites. The procedure was usually performed as a clinic procedure, using a 27-gauge needle.

RESULTS

The mean follow-up time was 14.5 +/- 11.3 months (range 6.0-48.0 months). Intraocular pressure (IOP) decreased from 28.8 +/- 6.8 mmHg (range 19.0-40.0 mmHg) to 15.3 +/- 5.2 mmHg (range 7.0-35.0 mmHg). Twelve eyes (46.2%) achieved success, defined as IOP < or = 18 mmHg without medication; 11 eyes (42.3%) achieved qualified success, defined as IOP < or = 18 mmHg with antiglaucomatous medication, and three of 26 eyes (11.5%) were classified as failures. The success rate after the initial needling was 64% at 6 months and the same after 1 year and 2 years. The success rate after one or more needlings was 96% at 6 months and 77% at 1 year and 2 years. Complications developed in six of the 26 eyes (23.1%). These involved transient corneal epithelial defects in three eyes (11.5%), temporary conjunctival wound leak in two eyes (7.7%), and development of bullous keratopathy in one high risk eye (3.8%).

CONCLUSION

Our results are comparable to the results of other studies. Needling revision appears to be a useful tool in the management of glaucoma.

Postoperative 5-fluorouracil versus intraoperative mitomycin C in high-risk glaucoma filtering surgery: extended follow up

PURPOSE

To compare the long-term efficacy and safety of postoperative subconjunctival 5-fluorouracil (5-FU) injections with that of intraoperative mitomycin C (MMC) in eyes at high risk for failure of trabeculectomy.

METHODS

In a retrospective, non-randomized comparative trial, 36 eyes of 36 consecutive patients at high risk for failure of trabeculectomy underwent glaucoma filtering surgery with either postoperative subconjunctival 5-FU injections (19 eyes) or intraoperative application of MMC (17 eyes). Intraocular pressure, number of postoperative antiglaucoma medications, postoperative visual acuity, interventions, and complications were evaluated.

RESULTS

Overall success (intraocular pressure </=21 mmHg) at 1 year was 73.6% in the 5-FU group and 82.3% in the MMC group. The cumulative 4-year success was 52.6% in the 5-FU group and 60.5% in the MMC group (P = 0.6). At 4-year follow up, mean +/- SD intraocular pressures were 17.58 +/- 4.01 mmHg in the 5-FU group and 13.33 +/- 3.36 mmHg in the MMC group (P = 0.01). There was no significant difference in the number of post-operative medications (P = 0.84), appearance of blebs (P = 0.20), final visual acuity (P = 1.00), and complications (P > 0.05) between the groups.

CONCLUSIONS

These results suggest that both postoperative 5-FU injections and intraoperative MMC application have long-term success in high-risk patients. However, MMC results in a greater decrease in intraocular pressure than 5-FU.

Trabeculectomy with or without mitomycin-C for paediatric glaucoma in aphakia and pseudophakia following congenital cataract surgery

PURPOSE

To evaluate the safety and efficacy of trabeculectomy with or without mitomycin-C (MMC) in the management of glaucoma in aphakia and pseudophakia following congenital cataract surgery.

PATIENTS AND METHODS

All patients of glaucoma with aphakia or pseudophakia who underwent trabeculectomy with or without MMC from January 1989 to April 2000 were included. The medical records of 19 consecutive patients (23 eyes) were reviewed. Data collected from a retrospective chart review were analysed. Outcome measures were evaluated using Kaplan-Meier survival analysis. Pre- and postoperative intraocular pressures (IOPs), visual acuities, success rate, bleb characteristics, surgical failure and complications were the main outcome measures. Successful IOP control was defined as an IOP between 6 and 21 mmHg, without antiglaucoma medications, without further antiglaucoma surgery and without any sight-threatening complication.

RESULTS

The mean age of patients was 8.8+/-5.5 years at the time of trabeculectomy with MMC compared to 11.0+/-12.4 years for trabeculectomy without MMC. Eight patients underwent trabeculectomy with MMC and 11 patients underwent trabeculectomy without MMC. There was no statistically significant difference between the two groups in terms of visual acuity, IOP, antiglaucoma medications, age at cataract surgery and at trabeculectomy. The IOP reduced from a preoperative level of 34.2+/-8.9 mmHg (range: 20-52) to a postoperative level of 18.4+/-12.2 mmHg (range: 2-60) with a mean follow-up of 24.2+/-17.9 months. The mean reduction in IOP in the MMC group was 15.5+/-17.3 and 16.3+/-13.8 mmHg in the other group (P = 0.967). Overall, complete success was achieved in 36.8%, qualified success in 21.1% and surgical failure in 42.1% of patients with a mean follow-up of 24.2+/-17.9 months. There was no difference in the success between the two groups at the last follow-up. One patient developed bleb-related endophthalmitis in both eyes following trabeculectomy with MMC.

CONCLUSIONS

The success rate of trabeculectomy in glaucoma following congenital cataract surgery was 36.8% at the end of 3 years. The present study proves a poor success rate of trabeculectomy in a small series of aphakic Asian Indian patients even with the use of MMC.

Novel antisense oligonucleotides targeting TGF-beta inhibit in vivo scarring and improve surgical outcome

The scarring response is an important factor in many diseases throughout the body. In addition, it is a major problem in influencing results of surgery. In the eye, for example, post-operative scarring can determine the outcome of surgery. This is particularly the case in the blinding disease glaucoma, where several anti-scarring regimens are currently used to improve glaucoma surgery results, but are of limited use clinically because of severe complications. We have recently identified transforming growth factor-beta (TGF-beta) as a target for post-operative anti-scarring therapy in glaucoma, and now report the first study of novel second-generation antisense phosphorothioate oligonucleotides against TGF-beta in vivo. Single applications of a TGF-beta OGN at the time of surgery in two different animal models closely related to the surgical procedure performed in glaucoma patients, significantly reduced post-operative scarring (P<0.05) and improved surgical outcome. Our findings suggest that TGF-beta antisense oligonucleotides have potential as a new therapy for reducing post-surgical scarring. Its long-lasting effects after only a single administration at the time of surgery make it particularly attractive clinically. Furthermore, although we have shown this agent to be useful in the eye, it could have widespread applications anywhere in the body where the wound-healing response requires modulation.

A new delivery system for 5-fluorouracil using prodrug and converting enzyme

AIMS

To evaluate a new delivery system of 5-fluorouracil (5-FU) using 5-fluorocytosine (5-FC) as a prodrug and cytosine deaminase induced in vitro and in vivo.

METHODS

Fibroblastic cells from rabbit Tenon's capsule were cultured. The cells were exposed to 5-FU and 5-FC with or without cytosine deaminase induced by recombinant adenovirus. In the in vitro study, cell proliferation and DNA synthesis were assessed by MTS, BrdU assay. The effect of 5-FC removal after the treatment of 5-FC and cytosine deaminase induction was also assayed. In the in vivo study cells with or without cytosine deaminase induction were transplanted into the subconjunctival space of mice, followed by eye drops of 1000 microg/ml of 5-FC three times a day. The mice were sacrificed at days 1, 5, and 10, then the cells transplanted were evaluated.

RESULTS

Cell proliferation was inhibited by exposure to 5-FU in a dose dependent manner; however, up to 1000 microg/ml of 5-FC did not affect cell proliferation. Cell proliferation was inhibited by exposure to 5-FC in a time dependent manner with induction of cytosine deaminase following infection of recombinant adenovirus. When 5-FC was removed 3 or 6 days after the treatment, the cells grew again. The effect was reproduced in the in vivo model of subconjunctival cellular proliferation although 5-FC was administrated as eye drops. There were no cases with corneal erosion.

CONCLUSION

Cell proliferation was inhibited by co-exposure of 5-FC and cytosine deaminase. This new delivery system may merit controlled delivery of 5-FU after filtering surgery.

In vitro and in vivo evaluation of an ocular delivery system of 5-fluorouracil microspheres

Solvent evaporation technique with O/O (oil/oil) emulsion was used to prepare 5-FU (5-fluorouracil) biodegradable microspheres with a polymer of poly(dl-lactide-co-glycolide) combining lecithin as an emulsifier. In vitro drug release was conducted in phosphate buffer with pH 7.4 at 37 degrees C. For in vivo studies, 10 mg of 5-FU microspheres (containing 1 mg of 5-FU) were implanted in the conjunctival area of the rabbit eye. Rabbits were sacrificed at certain time intervals within 7 days after drug application. Samples of aqueous humor and sclera were prepared and analyzed by the high performance liquid chromatography (HPLC) method. The tested 5-FU microsphere contained 10% drug with a mean particle size of 4.4 +/- 0.6 microm. The microsphere had a burst release initially (64.9 +/- 1.5%), followed by a sustained release; the cumulative release at time points of 1, 10 and 21 days were 71.9 +/- 1.9%, 80.1 +/- 2.1% and 89.8 +/- 2.3%, respectively. For in vivo studies, aqueous humor levels showed a peak at the first sampling point (2 hr), then maintained low levels of 5-FU with a range 0.2-1 microg/mL. Scleral levels were 20-80 microg/mL during a 7-day study. Our results indicate that the prepared 5-FU microsphere provided a long-term release for more than 1 week. The preparation showed no irritation and low toxicity (< 100 microg/mL). For application to the eye, it might be potentially useful as a complement drug system in glaucoma filtration surgery.

Long-term follow-up of initial 5-fluorouracil trabeculectomy in primary open-angle glaucoma in Japanese patients

PURPOSE

To evaluate the long-term efficacy and safety of initial trabeculectomy with subconjunctival 5-fluorouracil in Japanese patients with primary open-angle glaucoma.

SUBJECTS AND METHODS

Clinical records of 117 eyes from 117 patients with records of up to 14 years were retrospectively analyzed using the appropriate statistical methods.

RESULTS

The mean follow-up period was 6.2 +/- 3.6 years. Criteria for successful intraocular pressure control and success probability by Kaplan-Meier method at 12 years were intraocular pressure < 21 mm Hg without medication plus a 30% or more reduction in intraocular pressure, 50.4 +/- 5.2% (SE) 38.2 +/- 5.3%; and intraocular pressure < 16 mm Hg without medication plus a 30% or more reduction in intraocular pressure, 45.9 +/- 5.1% (36.5 +/- 5.2%). Cox multiple regression analysis showed that a younger age was associated with a higher success probability (P <0.01). Eyes with lower postoperative intraocular pressure tended to show more positive value of the MD slope (P = 0.0669), whereas 7% of successfully treated eyes showed a negative postoperative MD slope (P < 0.1). The probabilities for developing bleb leaks and bleb-related infections in eyes with a functioning bleb were 28.9 +/- 12.5% and 13.0 +/- 10.4% at 12 years.

CONCLUSION

Trabeculectomy with 5-fluorouracil as an initial surgery in Japanese patients with primary open-angle glaucoma was effective for long-term control of glaucoma. However, the probability of late-onset bleb-related complications was not low in eyes with a functioning bleb, stressing the importance of constant care regarding bleb status.

Small incision trabeculectomy: experiences with this new procedure for glaucoma surgery in Indian eyes

PURPOSE

The purpose of this study was to evaluate the potential advantages and disadvantages, success rate and complications of this new procedure for glaucoma surgery, which includes the formation of a filtration fistula without any dissection of the Tenon's capsule; as an alternative to trabeculectomy with or without pharmacological wound modulation.

METHODS

Small Incision Trabeculectomy avoiding Tenon's capsule was performed in 40 glaucomatous eyes through a 2.5 mm limbal incision and intraocular pressure was monitored serially over a period of 12 months.

RESULTS

The mean postoperative intraocular pressure (16.60+/-5.93 mmHg) at 12 months follow-up was significantly lower than the mean preoperative IOP (30.20+/-10.70 mmHg). Thirty-six eyes (90%) had IOP less than 22 mmHg without antiglaucoma medications at the end of the 12-month follow-up. Blebs were pale and diffusely elevated. No serious complications were encountered.

CONCLUSION

This new technique is a low-cost and safe alternative to conventional trabeculectomy that effectively reduces intraocular pressure. The use of a small 2.5 mm incision which obviates the dissection of the Tenon's capsule and subsequent subconjunctival fibrosis, the absence of requirement of any sophisticated instruments, and the absence of any major complications which are encountered with the use of anti-metabolites entails that this procedure be performed more often in glaucomatous eyes needing filtration surgery.

Long term results and complications of trabeculectomy augmented with low dose mitomycin C in patients at risk for filtration failure

AIM

To determine the results and complications up to 5 years after trabeculectomy with 0.02% mitomycin C (MMC) in glaucoma patients at risk for failure of filtration surgery.

METHODS

A consecutive series of 21 eyes from 20 patients who underwent trabeculectomy with MMC 0.02%, with an exposure time of 2 minutes, was retrospectively analysed and the results were compared with previously published data.

RESULTS

The mean preoperative intraocular pressure (IOP) was 28 mm Hg on an average of 2.8 glaucoma medications, and the mean postoperative IOP after 3 years was 14 mm Hg on an average of 0.4 medications. Three years after trabeculectomy, 17 of 21 (80.9%) eyes had an IOP of less than 21 mm Hg without medical treatment. Using Kaplan-Meier life table analysis the 5 year probability of an IOP less than 21 mm Hg without medication was 67% and with medication was 90%. Two patients required further glaucoma surgery during the first postoperative year, and another developed hypotonous maculopathy which was reversed after bleb revision. Seven patients developed visually significant cataract as a late consequence of the surgery. There were no bleb related infections.

CONCLUSION

In the long term MMC 0.02% used for 2 minutes intraoperatively is an effective adjunctive treatment in glaucoma patients at risk for bleb failure and in this dose is associated with few complications.

Combined cataract and glaucoma surgery

The management of cataract in glaucoma patients has been continuously changing over the past decade. Extracapsular cataract extraction has been replaced by small-incision phacoemulsification with foldable lenses, and in glaucoma surgery, adjunctive antifibrotic therapy based on risk factors for failure has become standard. Furthermore, new techniques in filtering and nonfiltering surgery have been suggested. The techniques, however, change so fast that well-controlled studies with a follow-up of more than 12 months are increasingly seldom. The purpose of this paper is to review the current literature and to point out some new ideas for the future investigation.

Overexpression of vascular endothelial growth factor (VEGF) in the retinal pigment epithelium leads to the development of choroidal neovascularization

Vascular endothelial growth factor (VEGF) has been strongly implicated in the development of choroidal neovascularization found in age-related macular degeneration. Normally expressed in low levels, this study investigates whether the overexpression of VEGF in the retinal pigment epithelium is sufficient to cause choroidal neovascularization in the rat retina. A recombinant adenovirus vector expressing the rat VEGF(164) cDNA (AdCMV.VEGF) was constructed and injected into the subretinal space. The development of neovascularization was followed by fluorescein angiography, which indicates microvascular hyperpermeability of existing and/or newly forming blood vessels, and histology. VEGF mRNA was found to be overexpressed by retinal pigment epithelial cells and resulted in leaky blood vessels at 10 days postinjection, which was maintained for up to 31 days postinjection. By 80 days postinjection, new blood vessels had originated from the choriocapillaris, grown through the Bruch's membrane to the subretinal space, and disrupted the retinal pigment epithelium. This ultimately led to the formation of choroidal neovascular membranes and the death of overlying photoreceptor cells. By controlling the amount of virus delivered to the subretinal space, we were able to influence the severity and extent of the resulting choroidal neovascularization. These results show that even temporary overexpression of VEGF in retinal pigment epithelial cells is sufficient to induce choroidal neovascularization in the rat eye.

Modulating conjunctival wound healing

Advances in molecular and cell biology have led to an expansion in our knowledge and understanding of the processes involved in wound healing. We review existing and potential therapies modulating the conjunctival scarring response, with particular reference to glaucoma filtration surgery. We discuss how the refinement of present antimetabolite regimens can minimise complications and improve surgical results, and advocate their use in carefully selected patient groups. Perhaps the most promising approach is targeting biological molecules. Hence, use of fully human neutralising monoclonal antibodies to the growth factor TGF beta has potential as a useful strategy for modifying conjunctival scarring. Combination therapies may also afford an improved therapeutic index. It is hoped that future therapies can offer safer, more specific, focal and titratable treatment, with far-reaching clinical applications.

Wound healing modulation after glaucoma surgery

Recent developments in molecular and cell biology have made a major impact on our understanding of the wound healing process and its modification. In this article, the spectrum of therapies that are either currently available or have potential application as modulators of the scarring response following glaucoma surgery are reviewed. Refinement of existing antimetabolite regimens can improve surgical results, especially in carefully selected patient groups. However, the most promising new approach appears to be using molecular-based therapies, such as fully human neutralizing monoclonal antibodies, designed to target specific molecules in the scarring response. Such strategies ultimately offer the potential of safer, more specific, focal, and titratable treatment, with far-reaching clinical applications.

Ab-interno goniotrabeculotomy versus mitomycin C trabeculectomy for adult open-angle glaucoma: a 2-year randomized clinical trial

OBJECTIVE

To evaluate the effect of ab-interno goniotrabeculotomy (AIGT) on the intraocular pressure (IOP) in adult patients with primary open-angle glaucoma (POAG), compared with the effects of mitomycin C trabeculectomy (MT).

DESIGN

Prospective, randomized, clinical trial.

PARTICIPANTS

Thirty-two eyes of 32 patients with medically uncontrolled POAG.

INTERVENTION

Standard limbus-based trabeculectomy with adjunct mitomycin C (0.3 mg/mL for 3 minutes) in 16 eyes of 16 patients; AIGT was performed in 16 eyes of 16 patients. The groups were matched for age, preoperative IOP, duration of preoperative antiglaucoma treatment, use of preoperative beta-blockers and parasympathomimetics, and use of beta-blockers in the fellow eye. The IOP (average of the two highest values measured in the diurnal curve, from 8 AM to 6 PM, every 2 hours) and complications were recorded 1, 3, 6, 12, 18, and 24 months after surgery.

MAIN OUTCOME MEASURES

Identification of complications and IOP.

RESULTS

All patients were followed up for 24 months. More postoperative complications occurred in the MT group during the 2-year follow-up. One month after surgery, IOP was 10 +/- 1.46 mmHg (range, 8-13) in the MT group and 12.12 +/- 1.63 mmHg (range, 8-14) in the AIGT group (Student's t test, P = 0.001). Three months after surgery, IOP was 11.5 +/- 1.59 mmHg (range, 8-14) and 12.75 +/- 1.57 mmHg (range, 10-16) in the MT and AIGT groups, respectively (Student's t test, P = 0.033). From the 6th to the 24th postoperative month, no statistically significant difference in IOP was found between the two groups. At the end of follow-up, 14 of 16 eyes (87.5%) of the AIGT group and 13 of the 16 eyes (81.25%) of the MT group showed an IOP < or = 14 mmHg.

CONCLUSION

Ab-interno goniotrabeculotomy appears to be a viable and safe surgical treatment for adult POAG. More extended follow-up, however, and a larger series of patients are needed to ascertain the actual effectiveness of this procedure in adult POAG.

Indocyanine green angiography and retinal sensitivity after photodynamic therapy of subfoveal choroidal neovascularization

Photodynamic therapy (PDT) is currently being evaluated in clinical trials for the treatment of choroidal neovascularization (CNV). Preliminary results indicate that PDT achieves immediate absence of leakage from CNV while maintaining visual acuity. Indocyanine green angiography reveals a reduction in CNV size and a persistent decrease in leakage activity after PDT. PDT appears to be characteristically accompanied by choroidal perfusion changes that regularly resolve within 3 months. Microperimetry shows an improvement of the central visual field with a decrease in scotoma size and intensity. Repeated PDT applications do not cause additional damage to the treated area, but might further enhance the recovery of macular function. A placebo-controlled, multi-center trial (TAP trial) evaluating the benefit of repeated PDT treatments in 3-month intervals is currently underway.

Delayed post-operative use of 5-fluorouracil as an adjunct in medically uncontrolled open angle glaucoma

PURPOSE

The current study was performed to evaluate the efficacy and safety of late post-operative use of subconjunctival 5-fluorouracil (5-FU) with ocular massage (OM) after trabeculectomy with or without intraoperative mitomycin C (MMC) in patients with medically uncontrolled primary open angle glaucoma (POAG).

METHODS

Initial trabeculectomy was performed in 60 eyes of 60 consecutive patients with medically uncontrolled POAG. Thirty eyes (group 1) were randomly assigned to intraoperative MMC (0.2 mg/ml for 3 min) and 30 (group 2) were randomised to standard trabeculectomy. During the first 3 months post-operatively OM and subconjunctival injections of 5-FU (5 mg in 0.5 ml of balanced salt solution) were performed in both groups every time the clinical evaluation suggested imminent bleb failure. Suture lysis was not performed in any patient.

RESULTS

Follow-up ranged from 14 to 53 months (mean 30.17, SD 9.23) in trabeculectomy + MMC treated eyes and from 6 to 54 months (mean 27.37, SD 10.83) in trabeculectomy treated eyes. During the first 3 months of follow-up OM and subconjunctival injections of 5-FU were performed in 14 cases in group 1 and in 18 cases in group 2 (p = NS). A positive response to OM was obtained in 14 of 14 eyes and in 14 of 18 eyes in group 1 and in group 2, respectively (p = 0.042). The difference in post-operative mean IOP between the two groups was statistically significant at each time interval studied (p < 0.001). Success (complete or qualified) was achieved in 50 of 60 eyes (83.33%): 28 (93.3%) in the trabeculectomy + MMC treated group and 22 (73.3%) in the trabeculectomy treated group (p = 0.039). Among the complications seen, the incidence of bleb fibrosis was higher in group 2 (p = 0.0026). By means of post-operative treatment four nonrandomised subgroups were identified: intraoperative MMC + post-operative 5-FU, intraoperative MMC + no post-operative 5-FU, no intraoperative MMC + post-operative 5-FU, no intraoperative MMC + no post-operative 5-FU. The eyes treated with intraoperative MMC and post-operative 5-FU had a better long-term (48 months) cumulative probability of success (100%); treatment with intraoperative MMC or post-operative 5-FU alone was followed by a success rate of 87.1% and 72.2%, respectively. The cumulative probability of success after only trabeculectomy was 56% (p < 0.05). One case of hypotony maculopathy was found in the subgroup treated only with intraoperative MMC.

CONCLUSIONS

This study confirms the effectiveness and relative safety of delayed post-operative 5-FU treatment in patients with clinical evidence of bleb failure. Only when OM had caused a lowering of IOP were late subconjunctival injections of 5-FU followed by good control of IOP. The use of intraoperative MMC may ensure a greater IOP decrease after OM.