Trabeculectomy with mitomycin C for refractory glaucoma in blacks

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.

Glaucoma care in West Africa

The authors draw on the peer review literature and 8 years of personal experience to provide an overview of the prevalence and management of glaucoma in West Africa.

Trabeculectomy outcomes in advanced glaucoma in Nigeria

BACKGROUND

Trabeculectomy remains the mainstay of therapy for advanced glaucoma in Nigeria due to the unavailability and expense of topical therapy. Little is known of the medium- to long-term outcomes of trabeculectomy in West Africa. Purpose To retrospectively assess outcomes, in terms of lowering of the intraocular pressure and preserving the visual acuity, and the safety of trabeculectomy in patients with advanced glaucoma in Nigeria.

METHODS

A retrospective case-note search was carried out from operating theatre records in a private hospital at Lagos, Nigeria from 1989 to 1997. Patients undergoing primary trabeculectomy with a minimum follow-up of 6 months were included in the study. Visiting consultants and registrars from the UK performed the surgery. Descriptive statistics and life-table analysis were applied to the data.

RESULTS

One hundred and forty-two eyes of 100 patients were included in the study. When the criteria for success were an intraocular pressure (IOP) of less than 22 mmHg, 30% reduction from pre-operative levels and a decrease in visual acuity of less than 3 Snellen chart lines, then by life-table analysis success rates were 85%, 82% and 71% at the 1, 2 and 5 year post-operative intervals respectively. Success rates were lower if an IOP of less than 16 mmHg was taken as one of the criteria (65%, 61% and 46% at the 1, 2 and 5 year intervals, respectively).

CONCLUSIONS

Trabeculectomy without antimetabolite use appears to be an effective way to lower the IOP of advanced glaucoma patients in Nigeria to less than 22 mmHg but not to less than 16 mmHg. The procedure, in experienced hands, is relatively safe with few major complications.

Trabeculectomy with mitomycin C in the treatment of post-traumatic angle recession glaucoma

AIM

The presence of traumatic angle recession is a risk factor for failure of glaucoma filtration surgery and a previous study has suggested that antimetabolite treatment should be used in these patients. This study was undertaken to determine for the first time the mid term results of trabeculectomy with intraoperative application of mitomycin C in patients with post-traumatic angle recession glaucoma.

METHODS

A retrospective analysis was made of 43 consecutive trabeculectomy procedures in 41 young black/mixed race patients followed for a mean period of 25 months (range 2-66 months). Mitomycin C 0.02% was applied between the sclera and conjunctiva for 1-5 minutes at the time of surgery. The intraocular pressure and visual acuity were measured postoperatively. The success of this technique was analysed by using a Kaplan-Meier cumulative survival curve.

RESULTS

The intraocular pressure was successfully controlled at last follow up without topical treatment in 77% (33/43 eyes) and the visual acuity was the same or better in 81% (35/43 eyes). Cumulative probability of success was 85% at 1 year follow up, 81% at 2 years, and 66% at 3 years and thereafter. Hypotonous maculopathy occurred in one patient and no cases of late bleb infection were found.

CONCLUSIONS

In medically uncontrolled post-traumatic angle recession glaucoma trabeculectomy with mitomycin C is an effective surgical procedure with an acceptable complication rate. Good intraocular pressure control and preservation of vision can be expected in most patients.

Revision of dysfunctional filtering blebs by conjunctival advancement with bleb preservation

PURPOSE

To assess the outcome of advancing a conjunctival flap with preservation of the bleb in eyes undergoing filtration bleb revision after trabeculectomy.

METHODS

A retrospective review of cases from a university-based referral practice identified 30 eyes of 30 patients that had undergone bleb revision after trabeculectomy by advancement of a conjunctival flap over the de-epithelialized bleb. Success was defined as resolution of the bleb-associated complication necessitating the revision (leak, hypotony, discomfort) with maintenance of intraocular pressure greater than or equal to 6 and less than or equal to 21 mm Hg without glaucoma medications. Qualified success met the above criteria but with the use of glaucoma medications. Summary data including visual acuity were obtained.

RESULTS

On the 30 eyes, 30 conjunctival advancement procedures were performed. Seventeen were for bleb leaks, 10 for prolonged hypotony without bleb leak, and three for dysesthetic bleb. Eighteen eyes (60%) were classified as a complete success and 24 eyes (80%) achieved at least a qualified success. Cumulative probability of at least qualified success was 77% at 2 years. Failures included inadequate intraocular pressure control (one eye), recurrent bleb leak (three eyes), and hypotony without bleb leak (two eyes). The mean preoperative intraocular pressure for all eyes increased from 4.4 +/- 3.7 mm Hg to 12.3 +/- 6.2 mm Hg (P <.00001) at the final visit with a mean follow-up of 18.9 +/- 15.5 months. Visual acuity improved or remained within 1 line of preoperative acuity in all but five patients. Complications included two patients with mild ptosis and four patients with hypertropia.

CONCLUSION

Advancement of a conjunctival flap with preservation the preexisting bleb often provides successful resolution of bleb-associated complications.

In vitro diffusion of mitomycin-C into human sclera after episcleral application: impact of diffusion time

The purpose of this study was to investigate the impact of different diffusion times of mitomycin-C (MMC) on the intrascleral concentration vs depth profile of MMC in an experimental model. Scleral quadrants of eight human donor eyes were exposed to sponges soaked with MMC for an application time of 1 min. After irrigation with 40 ml saline, we allowed further diffusion of MMC in the sclera for 1, 5, 14 and 29 min until the specimens were further processed. A central 8 mm diameter scleral disk was horizontally dissected with a kryotome at -20 degrees C. MMC concentrations of six layers of 140 microm thickness were analysed by means of high-performance liquid chromatography. The MMC concentrations (microg g(-1)) of layer 1 were: 13.45+/- 5.9 (mean +/- S.D. at 2 min diffusion time), 7.6+/-2.5 (6 min diffusion), 5.6+/-3.1 (15 min diffusion) and 3.6+/-1.7 (30 min diffusion). The corresponding MMC concentrations of layer 6 were: 0.61+/-0.48, 1.47 +/-0.66, 1.83+/-0.42 and 2.98+/-0.97 microg g(-1). The superficial concentration of intrascleral MMC decreased with increasing diffusion time, the deep concentrations increased. After 30 min of diffusion time, equal concentrations of MMC were found in all layers. Even with current low-dose application regimens of MMC the concentrations in the inner side of the sclera rapidly increase beyond the limits of the therapeutic range. Owing to this fast diffusion of MMC, the only means of reducing ciliary body concentrations of MMC is to reduce the dose.

Long term results of glaucoma surgery among participants in an east African population survey

AIM

To evaluate the long term results of glaucoma surgery among people in East Africa.

METHODS

Participants in a population based survey of eye disease prevalence were offered glaucoma surgery using standardised criteria. Either surgical iridectomy or trabeculectomy was carried out as indicated by a medical officer or by one of two ophthalmologists. Trabeculectomy methods included releasable sutures and mitomycin C in the majority of eyes. Subjects were examined during the first week and 2 months after surgery. Nearly 3 years later, re-examination was carried out in those who were still resident in the region.

RESULTS

Among 46 people who were offered iridectomy, trabeculectomy, or combined cataract extraction/lens implant/trabeculectomy, 21 people underwent surgery (46%). Of the 21, 19 were re-examined at 3 years (90%), including 16/18 eyes after trabeculectomy. Among these, intraocular pressure (IOP) declined from 29.9 (SD 9.4) mm Hg to 14.7 (5.9) mm Hg, with 16 of 18 eyes (89%) achieving a reduction > 25%. Hypotony maculopathy, late bleb leak, and late endophthalmitis were not detected. Visually significant cataract developed in 5/15 re-examined eyes that underwent trabeculectomy alone (33%), possibly associated with pre-existing cataract and diagnosis of angle closure glaucoma, but not with mitomycin C use.

CONCLUSIONS

Nearly half of those with glaucoma among residents of rural African villages accepted the offer of surgical therapy. While technical success was achieved at satisfactory levels, the development of cataract must be considered an important issue for application of glaucoma surgical therapy programmes.

Combined pars plana vitrectomy and glaucoma drainage implant placement for refractory glaucoma

PURPOSE

To report visual acuity and intraocular pressure outcomes among patients who have undergone combined pars plana vitrectomy and placement of a glaucoma drainage implant.

METHODS

The medical records of all patients who underwent combined pars plana vitrectomy and placement of a glaucoma drainage implant at the Bascom Palmer Eye Institute by one of the authors between January 1, 1990, and February 28, 1998, were reviewed. Forty patients (40 eyes) were identified, including 14 patients with neovascular glaucoma secondary to proliferative diabetic retinopathy or central retinal vein occlusion, 15 patients with other posterior segment disease, seven patients with secondary angle-closure glaucoma, and four patients with aphakia with ruptured anterior hyaloid face. Main outcome measures included visual acuity and intraocular pressure at 1 year postoperatively.

RESULTS

At 1 year postoperatively, 31 (77.5%) of 40 patients had stable or improved visual acuity; three eyes (7. 5%) had a final visual acuity of no light perception and three additional eyes (7.5%) were enucleated (because of chronic pain in two eyes and endophthalmitis in one eye). Mean preoperative intraocular pressure was 34 mm Hg and the median number of preoperative antiglaucoma medications was two. At 1 year postoperatively, mean intraocular pressure was 13 mm Hg and the median number of antiglaucoma medications was zero. Twenty-two patients (55.0%) achieved an intraocular pressure greater than 5 mm Hg and less than or equal to 21 mm Hg without antiglaucoma medication, and an additional seven patients (17.5%) achieved this level of intraocular pressure control with medication. Only one patient (2.5%) underwent further glaucoma surgery for uncontrolled intraocular pressure.

CONCLUSIONS

Although combined pars plana vitrectomy and placement of a glaucoma drainage implant is often a successful management option in selected patients with refractory glaucoma, visual outcome may be poor because of severe underlying ocular disease and postoperative complications.

The safety and efficacy of mitomycin C in endonasal endoscopic laser-assisted dacryocystorhinostomy

PURPOSE

The adjunctive use of mitomycin C (MMC) in glaucoma and pterygium surgery has been widely published, but there has not been any large long-term study of its use in endonasal endoscopic laser-assisted dacryocystorhinostomy (ELA-DCR). The purpose of this study was to examine the safety and efficacy of the adjunctive use of MMC in this procedure.

METHODS

A nonrandomized, retrospective, single-masked, interventional case-controlled study was performed wherein 123 consecutive procedures using MMC in ELA-DCR procedures, using the Holmium:YAG laser, were compared with a historical control group consisting of 48 consecutive procedures in which MMC was not used. One surgeon performed all procedures. The two groups were compared with regard to complications as well as success rate. The main outcome measures for success were the resolution of epiphora and patency with lacrimal irrigation. Success rates were analyzed using the Fisher's exact test. The main outcome determinants for complications were the presence or absence of delayed wound healing, wound necrosis, infection, or excessive bleeding. Postoperative follow-up interval ranged from 30 months to 72 months.

RESULTS

There were no complications in the group receiving MMC. One case of turbino-septal synechia formation occurred in the non-MMC group. The success rate of the MMC group was 99.2% compared with 89.6% in the control group. This difference (9.6%) was statistically significant using Fisher's exact test (p = 0.007).

CONCLUSION

This study supports the safety and efficacy of the intraoperative use of MMC in endonasal ELA-DCR.

Trabeculectomy with mitomycin-C in the treatment of pediatric glaucomas

PURPOSE

To evaluate the effectiveness and safety of trabeculectomy with mitomycin-C (MMC) in the management of childhood glaucomas.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

All patients less than 18 years of age who underwent trabeculectomy with MMC from June 1991 through October 1997 were included.

METHODS

The medical records of 29 consecutive patients (29 eyes) were reviewed. Data collected during routine patient follow-up were analyzed. Surgical outcome was evaluated using Kaplan-Meier life-table analysis.

MAIN OUTCOME MEASURES

Clinical outcome assessment included intraocular pressure (IOP) control, visual acuity, and identification of complications. Successful IOP control was defined as 5 mmHg < or = final IOP < or = 21 mmHg, with or without antiglaucoma medications and without further glaucoma surgery or loss of light perception. Outcomes for the group of patients with primary infantile glaucoma were compared with those for the group with secondary glaucomas.

RESULTS

Mean patient age was 6.4 +/- 4.4 years (range, 0.2-15.3 years). A variety of primary and secondary glaucomas were represented. Mitomycin-C (0.5 mg/ml) on a surgical sponge was applied to the episcleral surface for an average of 3.8 +/- 1.0 minutes (range, 1.5-5.0 minutes). Mean follow-up time for patients categorized as successes was 25.1 +/- 16.0 months (range, 5.5-59.7 months). The 12-, 24-, and 36-month life-table success rates for IOP control were 82%, 59%, and 59% respectively. There was no difference between the primary infantile glaucoma group and the secondary glaucoma group with respect to length of follow-up, rate of successful IOP control, and incidence of complications. Five patients (17%) experienced late bleb-related infection (BRI) at an average of 27.9 +/- 18.1 months (range, 5.4-55.5 months) after surgery. Other complications included hyphema, retinal detachment, late-onset bleb leak, flat anterior chamber, chronic hypotony, decompression retinopathy, suture abscess, and phthisis.

CONCLUSIONS

Trabeculectomy with MMC may be useful in the management of childhood glaucomas in which goniotomy, trabeculotomy, or both have failed. However, the high incidence of BRI in this series over an extended follow-up interval dictates caution in using MMC as an adjunct in pediatric trabeculectomy.

Intrascleral concentration vs depth profile of mitomycin-C after episcleral application: impact of irrigation

Mitomycin-C has been reported to cause toxic effects on the ciliary body after episcleral application during glaucoma surgery. We investigated the intrascleral diffusion of mitomycin-C in an experimental model. The episcleral sides of scleral quadrants of 14 human donor eyes were exposed for 5 min to sponges (corneal light shield, Merocel corp., Mystic, CT, U.S.A.) soaked with 200 microg ml(-1)mitomycin-C. After the exposure one of four quadrants was not irrigated and the episcleral sides of three quadrants were irrigated with 40, 100 and 200 ml saline. A 9 mm scleral disk was punched out with a trephine and frozen on a kryotome plate 2 min after the end of mitomycin-C exposure. An 8 mm diameter scleral disk was then cut with a trephine, again frozen on a kryotome plate and then horizontally dissected with a kryotome. For analysis purposes seven cuts of 20 microm thickness were combined to one layer of 140 microm. Six layers could be reproduced and were analysed. The mitomycin-C concentrations of these layers were analysed by high-performance liquid chromatography. A concentration vs depth profile was calculated for each group, and the half-width of concentration was calculated by log-linear regression. The mitomycin-C concentration of layer 1 was 24.51 microg g(-1)(+/-7.52) without irrigation, 13.15 microg g(-1)(+/-4.38) after 40 ml irrigation, 10.29 (+/-3.53) after 100 ml irrigation and 8.4 microg g(-1)(+/-1.62) after 200 ml irrigation. In layers 1-3 the concentration of mitomycin-C was significantly reduced by irrigation (ANOVA). In the deeper intrascleral layers irrigation had no effect on the mitomycin-C concentrations. Between layers 2 and 6 the half-width of the mitomycin-C concentration was 101 microm (no-irrigation group), 141 microm (40 ml irrigation group), 153 microm (100 ml irrigation group), and 164 microm (200 ml irrigation group). Irrigation reduced the mitomycin-C concentration only down to half of the scleral thickness, leaving the deep intrascleral concentrations unchanged.

Cellular photoablation to control postoperative fibrosis in filtration surgery: in vitro studies

The purpose of this study was to evaluate the feasibility of cellular photoablation using fluorescence-generated photoreaction products as a method to control postoperative fibrosis in filtration surgery. The fluorescent probe, 2', 7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester (BCECF-AM) is a cell membrane permeable compound rendered membrane-impermeable and fluorescent upon cleavage by intracellular esterases. Human scleral and Tenon's capsule fibroblasts were cultured and used as the target cells. Uptake and retention of the probe were determined with a fluorescence multi-well plate reader. Fibroblasts with or without intracellular probe were irradiated under conditions of fluorescence microscopy with diffuse blue light (450-490 nm, 1.68x10(2)mW m(2-1)). The viability of cells was examined by trypan blue exclusion and crystal violet test. To better mimic a wound healing process the effect of cellular photoablation was verified in artificial lesions produced in cultured monolayers loaded with different concentrations of the probe. Uptake and retention of BCECF-AM is dependent on ambient concentration. When incorporated the probe is lethal to those cells exposed to the appropriate photo-irradiation. Cells exposed to BCECF-AM (for 45 min) at a concentration of approximately 10 microm and irradiated for 1 min resulted in 100% cell death. Cellular photoablation in contrast to chemotherapeutic agents acts only on the targeted cells. This method shall be pursued as an alternative therapy to control postoperative fibrosis in filtration surgery.

Outcome of trabeculectomy with mitomycin-C in the iridocorneal endothelial syndrome

PURPOSE

Eyes with iridocorneal endothelial (ICE) syndrome have a high risk of failure in glaucoma filtering surgery failing. We investigated the efficacy of trabeculectomy with intraoperative mitomycin-C application in these patients.

DESIGN

Retrospective nonrandomized comparative trial with historical controls.

PARTICIPANTS AND CONTROLS

Ten patients with unilateral iridocorneal endothelial (ICE) syndrome were reviewed. Their intraocular pressures could not be controlled medically. In five eyes, this was the primary surgery performed. Five of the patients had undergone prior intraocular pressure-(IOP) lowering surgery that had failed at the time enrolled. Results were compared with previously published case series of similar patients treated with trabeculectomy alone or trabeculectomy and subconjunctival 5-fluorouracil injections.

INTERVENTION

Intervention consisted of trabeculectomy with a limbus-based conjunctival flap and mitomycin-C application. The dosage of mitomycin-C was 0.4 mg/ml for 1 to 4 minutes (mean, 1.9 min).

MAIN OUTCOME MEASURES

Adequate control of IOP (without medication lower than 21 mm Hg).

RESULTS

In eight eyes the IOP remained well controlled (mean IOP, 12.1 mm Hg) over the entire length of available of follow-up (mean, 14.9 months). Two eyes required implantation of an aqueous tube shunt at 4 and 11 months, respectively, after trabeculectomy with mitomycin-C. One eye experienced visual loss of 3 Snellen lines because of hypotony maculopathy.

CONCLUSIONS

Trabeculectomy with mitomycin-C application offers a reasonable intermediate-term success rate in ICE patients, who are otherwise at high risk for failure of filtering surgery.

Cellular photoablation to control postoperative fibrosis in a rabbit model of filtration surgery

AIM

To evaluate the feasibility of cellular photoablation using fluorescence generated photoreaction products as a method to control postoperative fibrosis.

METHODS

The fluorescent probe, 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester (BCECF-AM) is a cell membrane permeable compound rendered membrane impermeable and fluorescent upon cleavage by intracellular esterases. Rabbits (ChBB:CH; n=20) received a unilateral subconjunctival injection of BCECF-AM (40, 70, 80, or 100 microg) 30 minutes before surgery followed by intraoperative illumination with diffuse blue light (450-490 nm; 51.9 x 10(3) cd/m(2)) for 10 minutes. Controls received either the probe or illumination. Antifibrotic efficacy was established by clinical response and histological examination. Clinical response was assessed by comparing intraocular pressure (IOP) between the treated experimental eye and the fellow eye, which served as control. Success was defined by >20% difference in IOP.

RESULTS

IOP was significantly decreased in all groups within 4 days postoperatively. In control groups IOP rose within 10 days to normal levels. This was similar in the group receiving 40 microg of BCECF-AM. In the other groups (subconjunctival injection of 70-100 microg BCECF-AM) IOP was significantly (p < 0.02) decreased for 2-3 weeks. Clinical and histological examination revealed no toxic damage to adjacent tissues.

CONCLUSIONS

Cellular photoablation in contrast with chemotherapeutic agents acts on cells that have incorporated BCECF-AM and have been exposed to light at the appropriate wavelength. Though safety and reliability demand further studies this method might be an useful therapeutic approach to control postoperative fibrosis in humans undergoing filtration surgery.

Scleromalacia following trabeculectomy with intraoperative mitomycin C

PURPOSE

To report the development of scleromalacia in pediatric age as a complication of trabeculectomy with the adjunctive use of intra-operative mitomycin C.

PATIENTS

Reported are 2 patients who developed scleromalacia following trabeculectomy combined with intra-operative 0.4 mg/ml mitomycin C application for 5 minutes for refractory glaucoma in aphakic bullous keratopathy and penetrating keratoplasty.

RESULTS

Scleromalacia localised in the surgical area developed in 2 young patients. Scleromalacia remained stable in both patients after 6 and 24 months follow-ups.

CONCLUSIONS

It is suggested that this procedure be done more selectively, especially in young patients, with a shorter application time and using a lower concentration.

Outcomes of primary phakic trabeculectomies without versus with 0.5- to 1-minute versus 3- to 5-minute mitomycin C

PURPOSE

To compare the intraocular pressure and hypotony outcomes of primary phakic trabeculectomies with no mitomycin C (MMC), shorter MMC, and longer MMC exposure.

METHODS

We evaluated primary phakic trabeculectomies with no MMC (36 eyes of 36 patients), 0.5- to 1-minute MMC (50 eyes of 50 patients), and 3- to 5-minute MMC (38 eyes of 38 patients) at the concentration of 0.5 mg/ml. Successful trabeculectomy was defined as an intraocular pressure of 21 mm Hg or less without development of a marked visual acuity loss associated with prolonged hypotony (intraocular pressure < 6 mm Hg over 3 months) and without the need for additional surgery to control intraocular pressure or treat postoperative complications.

RESULTS

The three groups were similar in demographics, preoperative intraocular pressure, and medical dependency. However, the incidence of hypotony during the postoperative periods of 3 to 12 months was significantly higher in the 3- to 5-minute MMC group (P < .05, chi-square test). Severe visual acuity loss associated with hypotony was also more frequently found in the 3- to 5-minute MMC group than in the 0.5- to 1-minute (P = .009, chi-square test) group or the control group (P = .014, chi-square test). In addition, the success probabilities were significantly different among the three groups (P = .001, Kaplan-Meier survival analysis with log-rank test) and were the highest in the 0.5- to 1-minute MMC group and the lowest in the 3- to 5-minute MMC group.

CONCLUSION

Shorter application (0.5 to 1 minute) of MMC appears to be optimal for the successful outcome of primary phakic trabeculectomy compared with no MMC or longer application of MMC at a concentration of 0.5 mg/ml.

Dysfunctional filtering blebs

Guarded filtration surgery, is commonly used to control the intraocular pressure (IOP) in glaucomatous patients. Filtration surgery lowers the IOP by creating a fistula between the inner compartments of the eye and the subconjunctival space (i.e., filtering bleb). There are several options to improve the function of filtering blebs and to prevent their failure. However, improvement of IOP control after guarded filtration procedures is associated with a higher frequency of bleb-related complications. Early (e.g., bleb leak, excessive filtration, flat anterior chamber, filtration failure) and late (e.g., bleb leak, excessive filtration and hypotony, symptomatic blebs, bleb encapsulation, filtration failure, bleb infection) complications associated with filtering procedures should be managed adequately to prevent further problems. Techniques to improve the function of filtering blebs and to treat postoperative complications have progressed over the past decade.

Incidence of delayed onset infection after trabeculectomy with adjunctive mitomycin C or 5-fluorouracil treatment

AIMS/BACKGROUND

The introduction of the adjunctive use of antiproliferatives to trabeculectomy has greatly improved the success rate of this operation. Trabeculectomy with antiproliferative treatment, however, is usually associated with a cystic and thin walled filtering bleb, which may be more susceptible to infection. The objective of this study was to evaluate the incidence, clinical findings, and risk factors of delayed onset, bleb related infection after trabeculectomy with adjunctive mitomycin C (MMC) or 5-fluorouracil (5-FU) treatment.

METHODS

The records of 632 glaucoma patients who underwent 966 trabeculectomies, with and without the use of adjunctive MMC or 5-FU treatment, between January 1985 and February 1995 were analysed. The mean follow up period was 3.5 (2.4) years (range 0.1 to 11.2 years). The mean patient age was 54.8 (18.8) years (range 0 to 88 years).

RESULTS

Bleb related infection occurred in one of 76 trabeculectomies that did not receive antiproliferatives (1.3%), three of 228 treated with 5-FU (1.3%) trabeculectomies, and seven of 662 treated with MMC (1.1%). Five eyes developed blebitis; six eyes developed endophthalmitis. Bleb related infection developed an average of 3.1 (1.6) (range 0.4 to 6.0) years after trabeculectomy. All eyes had avascular or hypovascular blebs that were cystic in shape before infection and all eyes had reduced intraocular pressure. Early wound leaks and chronic, intermittent bleb leaks were identified to be risk factors for the bleb related infection.

CONCLUSION

The incidence of delayed onset, bleb related infection after trabeculectomy with antiproliferative treatment is similar to that after trabeculectomy without antiproliferatives.

Trabeculectomy with intraoperative sponge 5-fluorouracil in Afro-Caribbeans

AIM

To study the efficacy and safety of intraoperative 5-fluorouracil (5-FU) in Afro-Caribbean patients.

METHODS

The results of trabeculectomy in 18 eyes of 18 Afro-Caribbean patients in whom a sponge soaked in 25 mg/ml solution of 5-FU was applied between Tenon's capsule and sclera for 5 minutes before excision of the trabecula were compared with 16 eyes of 16 Afro-Caribbean patients matched for age, quantity, and duration of preoperative medications, who underwent trabeculectomy without 5-FU.

RESULTS

The mean postoperative intraocular pressure (IOP) at 1 month was 15.6 (SD 6.1) mm Hg in the 5-FU group and 18.0 (5.2) mm Hg in the control group (p = 0.15). There was no significant difference in the IOP at 6, 12, 15, 18, and 24 months in the two groups. Success rate at 18 months defined as an IOP less than or equal to 21 mm Hg with no adjunctive medication was 56% in the 5-FU group and 55% in the control group. No major complications were noted in either group.

CONCLUSION

Intraoperative sponge 5-FU alone is safe but does not appear to decrease the risk of failure of trabeculectomy in Afro-Caribbeans.

Decorin and suramin inhibit ocular fibroblast collagen production

BACKGROUND

The process of ocular wound healing with respect to glaucomatous filtering procedures is of current interest. Delaying this response in patients could possibly lead to more favorable surgical results. So far, only highly toxic antimetabolites have come into frequent clinical use. The possible efficacy of other groups of substances such as growth factor inhibitors has not yet been examined in vitro.

METHODS

We exposed Tenon's capsule fibroblasts in tissue culture to various concentrations of decorin and suramin. The dose responses of type I and type III collagen to these inhibitors were measured using an ELISA-type dot blot assay. Total cellular protein production was assayed by measuring the incorporation of tritiated leucine.

RESULTS

At a concentration of 10 micrograms/ml, suramin reduced the collagen production by more than 80%. Decorin, at a concentration of 100 micrograms/ml, reduced type I collagen production by about 50% while type III collagen was reduced by 80%. At these concentrations, the total cellular protein production was not inhibited.

CONCLUSIONS

Both suramin and decorin, which specifically inhibit the action of growth factors on target cells, reduce the production of collagen synthesis by Tenon's capsule fibroblasts. This is a specific effect, because total protein production is not influenced. This sets these substances apart from antimetabolites. Decorin and suramin may have clinical relevance in that they appear to interfere with ocular wound healing more specifically than the substances so far frequently used.

Transconjunctival application of mitomycin C in combination with laser sclerostomy ab interno: a long-term morphological study of the postoperative healing process

The precise mechanism whereby mitomycin C enhances IOP reduction in glaucoma filtering surgery still eludes us. Ten rabbits received full-thickness Nd:YAG laser sclerostomy ab interno and adjunctive intraoperative treatment with mitomycin C (MMC) applied topically over the intact conjunctiva (0.5 mg ml-1 for 5 min). A systematic ultrastructural analysis of the fistulas and surrounding tissue was then conducted in conjunction with clinical observations, over the ensuing 10 weeks. In order to investigate also the extent to which MMC impedes fistula occlusion in the absence of percolating aqueous humour, we created non-perforating ('half-thickness') sclerostomies ab interno in three additional rabbits, one with and two without MMC therapy. Transconjunctival MMC application resulted in no serious complications. Eight of the ten full-thickness fistulas remained patent throughout the study, maintaining significant IOP reduction; the other two sclerostomies were compromised by iris incarceration. The MMC-treated, half-thickness canal remained as a tissue-free cul de sac; the two non-treated ones became completely occluded within one week without having recourse to extraocular cell populations. MMC suppressed the migration and proliferation of fibroblasts, macrophages and clump cells from the episclera, sclera, ciliary body and iris root. Repolymerization of heat-damaged collagen was abortive; neosynthesis was not observed. Myofibroblasts were encountered in the vicinity of the sclerostomy canals, and, after the fifth week, these cells were also found to be deployed as a canal-lining layer, delimiting the lumen from the surrounding stroma along most of the fistula length. Towards the external ostium, this layer of myofibroblasts was incomplete or absent. Near the internal ostium, lining cells were derived from the corneal endothelium. The transconjunctival mode of applying MMC appears to be efficient. This antifibrotic drug exerts its inhibitory influence by suppressing not only cell migration and proliferation, but also phagocytic and synthetic activities. However, exposed tissues are not acellular, and amongst the populations present, myofibroblasts are found to dominate the scene. The canal-delimiting cellular lining may play a role in maintaining fistula patency in MMC-treated eyes.

Glaucoma associated with uveitis

Raised intraocular pressure is a common and frequently serious complication of anterior uveitis. The milieu of inflammatory cells, the mediators they release, and the corticosteroid therapy used to treat the uveitis can participate in the pathogenesis of uveitic glaucoma. These factors alter the normal anatomic structure of the anterior chamber and angle, influencing aqueous production and outflow. These changes act to disrupt the homeostatic mechanisms of intraocular pressure control. Structural changes in the angle can be acute, such as in secondary angle closure with pupillary block glaucoma, or chronic, such as combined steroid-induced and secondary open angle glaucoma. Management of uveitic glaucoma may be difficult because of the numerous mechanisms involved in its pathogenesis. Diagnostic and therapeutic decisions are guided by careful delineation of the pathophysiology of each individual case. The goal of treatment is to minimize permanent structural alteration of aqueous outflow and to prevent damage to the optic nerve head. This article reviews the pathogenesis of uveitic glaucoma, with specific attention to etiology. Medical and surgical therapies are also discussed, with emphasis on the more recent developments in each category.

Mitomycin C dissolved in a reversible thermosetting gel: target tissue concentrations in the rabbit eye

AIMS

To determine whether a new, reversible thermosetting gel enhances mitomycin C transfer to target ocular tissues in the rabbit eye.

METHODS

A 0.1 ml solution of mitomycin C containing 0.22 microgram, 2.9 micrograms, or 28 micrograms of the agent dissolved in a reversible thermosetting gel consisting of methylcellulose, citric acid, and polyethylene glycol was injected subconjunctivally in 30 New Zealand albino rabbits. Scleral and conjunctival tissues were excised at 0.5, 1, 2, 4, or 24 hours after the injection and mitomycin C concentrations in these tissues were determined by high performance liquid chromatography. The concentration over time was approximated to a single exponential curve, and initial mitomycin C concentrations, time constants, and half life values were determined. Finally, the areas under the curves (AUCs) between 0.5 and 24 hours were calculated.

RESULTS

The mitomycin C concentrations in the target tissues were dose dependent and decreased rapidly over 24 hours. Both the initial mitomycin C concentrations as well as AUCs in these eyes treated with mitomycin C, dissolved in a reversible thermosetting gel, were higher than those in eyes treated similarly in a previous study in which the gel was not used.

CONCLUSION

Applied subconjunctivally in the rabbit eye, mitomycin C dissolved in the reversible thermosetting gel enhanced transfer of the agent to the sclera and the conjunctiva.

Primary glaucoma triple procedure with or without adjunctive mitomycin. Prognostic factors for filtration failure

PURPOSE

The prerequisite for selective use of adjunctive mitomycin C (MMC) in primary glaucoma triple procedure (PGTP) is a better understanding of the prognostic factors. Therefore, the authors carried out the current study on the outcome of PGTP with and without adjunctive MMC to determine the prognostic factors for filtration failure of PGTP.

METHODS

The study patients consisted of 174 consecutive primary open-angle glaucoma (POAG) patients undergoing PGTP. They were assigned randomly to either no adjunctive MMC (93 eyes of 93 patients) or adjunctive subconjunctival MMC (81 eyes of 81 patients) during the PGTP. After surgery, the patients were examined at regular intervals for visual acuity, intraocular pressure (IOP) control, medical therapy requirements, and complications. Filtration failure was determined according to two different criteria: (1) a less stringent set of criteria (criterion I) and (2) a more stringent set of criteria (criterion II).

RESULTS

There were no statistically significant differences between the groups with and without adjunctive MMC with respect to postoperative IOP, number of medications, and visual acuity outcome during mean follow-up (+/- standard deviation) of 25.1 +/- 5.5 months (P > 0.05 for each). However, there were prognostic factors for filtration failure in the control group but not in the MMC group. Black race, diabetes mellitus, preoperative IOP greater than or equal to 20 mmHg, and number of preoperative medications greater than two were found to be significant prognostic factors for filtration failure by criterion I. Black race, preoperative IOP greater than or equal to 20 mmHg and number of preoperative medications greater than 1 were significant prognostic factors for filtration failure by criterion II.

CONCLUSION

There was no statistically significant difference in the overall outcome of PGTP between control and MMC groups of nonselected patients with primary open-angle glaucoma. Black race, diabetes mellitus (by criterion I only), preoperative IOP greater than or equal to 20 mmHg, and number of preoperative medications greater than 2 (by criterion I) or greater than 1 (by criterion II) were found to be significant independent prognostic factors for filtration failure of PGTP without adjunctive MMC but no with adjunctive MMC. The use of adjunctive subconjunctival MMC in PGTP may have to be selective, primarily in those patients with primary open-angle glaucoma with one or more of the prognostic factors for filtration failure.

Surgery for refractory glaucoma

PURPOSE

To determine the surgical outcome of mitomycin trabeculectomy in patients with refractory glaucoma.

METHODS

Sixty-six eyes of 52 patients with refractory glaucoma underwent mitomycin trabeculectomy. Mitomycin was applied for five minutes only once during trabeculectomy. The follow-up period was six to 61 months.

RESULTS

Cumulative success probability was calculated using Kaplan-Meier life-table analysis assuming the cut-off postoperative IOP to be 20 mmHg or IOP reduction by at least 20% in eyes with preoperative IOP 24 mmHg. At the end of 61-month follow-up the success probability was 80% +/- 6% without postoperative ocular hypotensive medication (complete success) and was 95% +/- 3% regardless of postoperative antiglaucoma medication (overall success), respectively.

CONCLUSION

The data suggest that mitomycin trabeculectomy is efficacious in reducing IOP in patients with refractory glaucoma.

Slit-lamp needle revision of failed filtering blebs using mitomycin C

PURPOSE

The purpose of the study is to determine the efficacy and safety of Mitomycin C (MMC) augmented slit-lamp needle revision of failed filtration surgery.

METHODS

The authors retrospectively reviewed the charts of 62 patients (62 eyes) (age, 72 +/- 15 years) with failed filtration surgery who underwent needle revision using MMC. A mixture of 0.01 ml of MMC (0.4 mg/ml) and 0.02 ml of bupivacaine with epinephrine was injected subconjunctivally. Twenty to 30 minutes later, a 30-gauge needle was used to perforate the area of subconjunctival fibrosis and re-establish flow.

RESULTS

Overall, 118 needing procedures (mean, 1.9 +/- 1.4 revisions per eye; range, 1-7) were performed on 62 eyes (mean follow-up, 9.9 +/- 3.7 months; range, 4.5-20.1 months). Thirty-six patients (58.1%) were needled once and 26 patients (41.9%) underwent more than 1 needling procedure. Intraocular pressure decreased from 24.1 +/- 6.4 mmHg (range, 18-44) before surgery to 11.5 +/- 4.8 mmHg (range, 1-26) at last follow-up (P = 5.51 x 10(-21)). Antiglaucoma medications decreased from 1.6 +/- 1.0 to 0.3 +/- 0.6 (P = 3.8 x 10(-14)). Successful single-needling procedure was highly correlated with race (white) and past conventional glaucoma filtration surgery of more than 4 years. Complications included serous choroidal detachment (10 eyes), suprachoroidal hemorrhage (1 eye), bleb leak (5 eyes), iris blocking sclerostomy (2 eyes), hyphema (2 eyes), corneal abrasion (2 eyes), and hypotony (1 eye).

CONCLUSION

Mitomycin needle revision appears to be an extremely effective way to revive failed filtration surgery. The incidence of complications compares favorably to trabeculectomy with MMC.

Bleb-related endophthalmitis after trabeculectomy with mitomycin C

PURPOSE

To determine whether filtering blebs resulting from adjunctive use of mitomycin C (MMC) leads to an increased risk of endophthalmitis.

METHODS

The authors retrospectively reviewed the records of 232 consecutive trabeculectomies performed at the W. K. Kellogg Eye Center with adjunctive use of MMC from May 1990 through June 1993. Data obtained from the records included patient age, sex, race, type of glaucoma, site of filtration surgery, concentration and duration of exposure to MMC, presence of early or late bleb leakage, and the occurrence of endophthalmitis.

RESULTS

Three patients were lost to follow-up less than 1 month after surgery. A total of 229 eyes of 192 patients (11 women and 82 men) were included in the study. Mean follow-up of patients remaining free of infection was 18.5 +/- 10.8 months (range, 1-44 months). The overall incidence of bleb-related endophthalmitis was 2.6%. Endophthalmitis developed in 8% of patients (4 or 50) in whom an inferior approach was used and in 1.1% (2 or 179) in whom a superior approach was used (P = 0.02, Fisher's exact test). The estimated odds ratio for the development of endophthalmitis after trabeculectomy with adjunctive MMC for inferior versus superior filtration sites was 7.7.

CONCLUSION

Short-term follow-up of trabeculectomies performed with adjunctive use of MMC demonstrates an overall incidence of endophthalmitis comparable to filtrationprocedures performed with 5-fluorouracil or without antifibrotic agents. However, inferior trabeculectomy performed with adjunctive MMC carries a significantly increased risk of bleb-related endophthalmitis compared with filters performed superiorly.

An ultrasound biomicroscopic study of filtering blebs after mitomycin C trabeculectomy

PURPOSES

To investigate the relation between filtering bleb function and ultrasound biomicroscopic images, and to establish a new classification system for filtering blebs according to these images.

METHODS

After trabeculectomy with mitomycin C, the filtering blebs of 117 eyes from 117 patients with various types of glaucoma were examined using ultrasound biomicroscopy. Four parameters of the images-intrableb reflectivity, visibility of the route under the scleral flap, formation of a cavernous fluid-filled space, and bleb height-were correlated with the level of intraocular pressure (IOP).

RESULTS

Reflectivity inside the bleb and visibility of a route under the scleral flap were highly associated with IOP control. Blebs were classified into four categories according to the four measured parameters: type L (low-reflective), type H (high-reflective), type E (encapsulated), and type F (flattened). Eyes with good IOP control had mainly type L blebs. Type E and type F blebs were seen mostly in eyes requiring additional medication.

CONCLUSION

The structure inside a filtering bleb is visible by ultrasound biomicroscopy, and bleb function is significantly associated with its ultrasound biomicroscopic image in eyes trabeculectomized with adjunctive mitomycin C.

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

PURPOSE

To compare the outcome of filtering surgery in high-risk patients using intraoperative mitomycin C (MMC) versus postoperative 5-fluorouracil (5-FU).

METHODS

In a randomized clinical trial, the use of postoperative subconjunctival injections of 5-FU in 19 eyes of 19 patients was compared with a single intraoperative application of MMC in 20 eyes of 20 patients. All eyes were at high risk for failure of glaucoma filtering surgery.

RESULTS

Follow-up ranged from 26 to 38 months (mean, 32.0 months). Three eyes in the MMC-treated group and two eyes in the 5-FU-treated group required subsequent surgery to control the IOP. Excluding these patients, intraocular pressure (IOP) averaged 9.0 +/- 4.9 mmHg in the MMC-treated eyes versus 16.3 +/- 4.6 mmHg in the 5-FU-treated eyes at the patient's last visit (P = 0.0003). Of the MMC-treated eyes, 81.3% had IOPs less than or equal to 12 mmHg compared with 26.7% of eyes in the 5-FU group (P = 0.0023). In the MMC-treated group, the average number of medications for IOP control at last visit was 0.5 +/- 0.8 compared with 1.6 +/- 1.3 in the 5-FU-treated group (P = 0.01). Late postoperative complications (those occurring more than 3 months after surgery) were similar for the two groups, with the exception of formation of a Tenon cyst in three of the eyes treated with MMC compared with none of the 5-FU-treated eyes.

CONCLUSIONS

Eyes treated with MMC have lower IOP on fewer medications than eyes treated with 5-FU. Late postoperative complications are similar with the exception of an increased incidence of Tenon cyst formation in the MMC-treated eyes.

Adjunctive mitomycin C in primary trabeculectomy in phakic eyes

PURPOSE

The addition of antiproliferative agents, most recently mitomycin C, has improved the outcome of glaucoma filtering surgery in eyes with a high risk of surgical failure. We conducted the present study to determine whether adjunctive mitomycin C would increase the success rate of primary trabeculectomies in phakic eyes.

METHODS

Thirty-three eyes of 33 consecutive patients with phakic primary open-angle glaucoma, who were predominantly black (24 black and nine white), who underwent primary trabeculectomy with adjunctive subconjunctival mitomycin C (0.5 mg/ml for three minutes) were compared with a demographically similar historical control group of 30 eyes of 30 consecutive patients (20 black and ten white) with phakic primary open-angle glaucoma, who had undergone primary trabeculectomy without an adjunctive antifibrotic agent.

RESULTS

Although the mean preoperative intraocular pressures were similar in both groups (29.0 +/- 6.4 mm Hg in the mitomycin C group and 29.5 +/- 10.0 mm Hg in the control group, P = .61), the mean postoperative intraocular pressure at each follow-up period was significantly lower in the mitomycin C group than in the control group (10.3 +/- 7.1 vs 14.5 +/- 5.1 mm Hg at six months, P = .02; 10.5 +/- 4.9 vs 14.5 +/- 4.4 mm Hg at 12 months, P = .01; and 10.0 +/- 3.1 vs 17.2 +/- 3.0 mm Hg at 18 months, P = .004, respectively). The mean number of postoperative medications was also significantly lower in the mitomycin C group (0.2 +/- 0.4 vs 1.1 +/- 1.4 medications at six months, P = .007; 0.3 +/- 0.4 vs 0.9 +/- 1.1 medications at 12 months, P = .04; and 0.3 +/- 0.5 vs 1.7 +/- 1.2 medications at 18 months, P = .01, respectively). However, the mitomycin C group had a significantly higher incidence of prolonged hypotony (intraocular pressure less than 6 mm Hg) compared with the control group (15% vs 0% at nine months, P = .05). Younger age was associated with a higher incidence of persistent hypotony.

CONCLUSIONS

Adjunctive subconjunctival mitomycin C (0.5 mg/ml for a three-minute exposure) in primary trabeculectomies of phakic eyes, while increasing the success rate by decreasing intraocular pressure and postoperative medications, is associated with a higher incidence of prolonged hypotony.

Short-term clinical results and complications of trabeculectomies performed with mitomycin C using different concentrations

Despite the fact that trabeculectomies performed with Mitomycin C (MMC) have a high rate of success as repeatedly reported, the rate of complications encountered draws much of the attention of this substance to those cases that are unsatisfactory. To ascertain a possible relationship between some of these complications and concentrations of MMC used, we performed, in a prospective study, trabeculectomies for complicated cases of glaucoma with either concentrations of 0.5 mg/ml of MMC (group 1) or 0.2 mg/ml of MMC (group 2). The two groups were followed-up for 6 months and consisted of 49 and 40 cases, respectively. Two eyes in the first group and 3 in the second had to be considered as surgical failures that developed increasingly high pressures. Complications included hypotony most frequently (33%, both groups) with severely decreased vision in 3 cases (6%) of the first group and 8 (20%) in the second. Other results including visual acuities, IOP, and the rate of other complications were not significantly different in both groups and indicate that there may be no large difference between the two concentrations of MMC used.

Filtering surgery with mitomycin-C in uncomplicated (primary open angle) glaucoma

Mitomycin is an antibiotic with antineoplastic activity which inhibits fibroblast proliferation in the operative field in glaucoma filtering surgery. The authors retrospectively evaluated the effectiveness of trabeculectomy with mitomycin-C as an initial surgical procedure in uncomplicated (primary open angle) glaucoma in 17 eyes of 17 patients; 12 eyes of 12 patients that received standard trabeculectomy constituted the control group. Mitomycin was applied at a concentration of 0.5 mg/ml for 3 min to the episclera and 2 min under the scleral flap. Median values for preoperative intraocular pressure was 43 mmHg (range 26-65) in the control group and 40 mmHg (range 30-60) in the mitomycin group (p > 0.05, Mann-Whitney U-test). After an average follow-up of 17 months, median postoperative IOP was 10 mmHg (range 3-18) in the control group and 4 mmHg (range 1.1-20) in the mitomycin group (p < 0.05, Mann-Whitney U-test). Percentage IOP drop was 75.6% in the control group (range 30.8-93.5%) and 89.6% (range 54.2-98%) in the mitomycin group (p < 0.05, Mann-Whitney U-test). The postoperative visual acuities of the two groups did not differ significantly (p > 0.05, Fisher exact test). Although there was not a statistically significant difference between complications, such as elevated intraocular pressure, wound leakage or bleb ulceration in both groups (p > 0.05, Fisher exact test), the number of hypotonous eyes (having an average IOP < or = 5 mmHg) was significantly higher in the mitomycin-C group compared to the controls (p < 0.05, Fisher exact test). Mitomycin established a well formed bleb and reduced the IOP more effectively than did the standard filtering procedure (p < 0.05, Mann-Whitney U-test); however, further work is necessary to evaluate the long-term complications of mitomycin-C surgery such as hypotony. This would help clear any doubts about the safety of this procedure on long-term.