Suppression of avascular bleb formation by a thin biodegradable film in a rabbit filtration surgery with mitomycin C

Background

Avascularity of the bleb is regarded as a risk of bleb infection, which is the most serious complication after filtration surgery with mitomycin C (MMC). There is no perfect way to prevent avascular bleb formation. We hypothesized that keeping the conjunctiva away from direct exposure to aqueous filtration may suppress avascular bleb formation after filtration surgery with MMC. In order to prove our hypothesis, we investigated whether a thin biodegradable, honeycomb-patterned film (HPF) can reduce bleb avascularity in a rabbit model of filtration surgery with mitomycin C (MMC).

Methods

A fornix-based full-thickness filtration surgery was performed in one eye of each of five rabbits (control group). The same surgery with intraoperative MMC treatment was done in both eyes of six rabbits, with one eye receiving a 14-μm-thick HPF made from poly(L-lactide-co-ε-caprolactone), which was placed subconjunctivally over the filtration site with the honeycomb surface facing up. Intraocular pressure (IOP) measurements, bleb evaluations using ultrasound biomicroscopy (UBM), and in vivo confocal microscopy (IVCM) were performed periodically for 4?weeks postoperatively followed by histological examination.

Results

The postoperative IOP decrease and bleb survival were significantly greater in MMC-treated eyes than in control eyes, and were similar between MMC-only and MMC + HPF eyes. The avascular area in the bleb persisted for 4?weeks in MMC-only eyes. Postoperative IVCM showed morphological changes of the conjunctival epithelial cells (i.e., enlarged and variable in size and shape) and epithelial defects in MMC-only eyes, and significantly lower density of connective tissue and vascularity in the subepithelial space in MMC-only eyes compared to the control eyes. These IVCM findings agreed with those by UBM and histology. Bleb avascularity shown by clinical bleb appearance, IVCM and histology, conjunctival epithelial damage shown by IVCM and histology, and loose subepithelial connective tissue shown by UBM, IVCM, and histology were all reduced in MMC + HPF eyes compared to MMC-only eyes.

Conclusions

IVCM successfully showed the characteristic conjunctival damage in MMC-treated blebs. The concomitant use of a thin biodegradable HPF reduced avascularity and conjunctival damage in blebs, without compromising filtration in rabbits following filtration surgery with MMC.     

Mitomycin C augmented glaucoma surgery: evolution of filtering bleb avascularity, transconjunctival oozing, and leaks

AIMS: To prospectively study the evolution of possible high risk features of conjunctival filtration blebs like avascularity, transconjunctival oozing (TCO), and leaks after mitomycin C (MMC) enhanced glaucoma surgery. METHODS: Single observer, 2 year prospective study on bleb characteristics of 125 eyes of 125 consecutive patients who had MMC augmented glaucoma surgery with initially successful filtration. MMC (0.2 mg/ml for 2 minutes in most cases) was applied on the area of the scleral flap before dissection. Glaucoma surgeries included were trabeculectomy, deep sclerectomy, and combined procedures. A dry fluorescein strip was applied on the avascular part of the bleb and observed for aqueous egress with flow (point leak, PL) or without (TCO). RESULTS: The mean time (95% CI) for observing bleb avascularity, TCO, and bleb leaks were 106 days (69 to 143), 208 days (155 to 261), and 609 days (559 to 659), respectively. Bleb leaks were observed in 17 eyes (13.6%)-15 (24.6%) in the trabeculectomy group and two (3.1%) in the deep sclerectomy group (p = 0.003). Kaplan-Meier survival analyses showed that the probability of observing bleb avascularity at sixth, 12th, and 24th month after surgery was 56%, 71%, and 73%, respectively. In eyes with avascular blebs, the probability of developing TCO and leaks was 77% and 1% at 6 months, 81% and 12% at 12 months, and 95% and 26% at 24 months, respectively. Cox's regression analyses and log rank tests showed that eyes with larger avascular blebs (>4 mm) were more likely to develop TCO (hazard ratio 3.77, p = 0.001) and delayed bleb leaks were more likely to be seen in eyes of the trabeculectomy group rather than the deep sclerectomy group (hazard ratio 0.06, p = 0.0006). CONCLUSIONS: MMC application over the area of scleral flap dissection during glaucoma surgery is associated with a high incidence of bleb avascularity, TCO, and delayed bleb leaks. Most eyes developed bleb avascularity within the first year after surgery. TCO will eventually be seen in all eyes with avascular blebs and the incidence of leaks gradually increases with time. This study shows that patients with eyes undergoing glaucoma surgery with MMC and avascular blebs should be monitored indefinitely.     

Bleb reduction and bleb repair after trabeculectomy

OBJECTIVE: To describe methods and outcomes for repair of bleb-related complications of trabeculectomy surgery. DESIGN: Retrospective, consecutive, noncomparative case series. PARTICIPANTS: Thirty-one persons having bleb revision by two surgeons at the Wilmer Institute from 1994 to the present. INTERVENTION: One of two types of revision surgery was performed: bleb reduction to decrease symptoms from large blebs or bleb repair to improve hypotony, using conjunctival rotation flap or free conjunctival autograft. MAIN OUTCOME MEASURES: Visual acuity, intraocular pressure (IOP), reported symptoms, complications, and number of glaucoma medications at the final visit. RESULTS: The mean time from trabeculectomy to bleb revision was 4.4 years. Bleb reduction was performed because of symptomatic, high blebs in 11 eyes of 11 persons. Bleb repair was performed to end bleb leakage in 13 eyes of 13 persons and to increase IOP in 8 eyes of 7 persons with hypotony. Median visual acuity improved from 20/50 before revision to 20/30 at most recent follow-up. Mean IOP increased after treatment from 7.7+/-4.9 to 12.4+/-4.0 mmHg (P < 0.001). Symptoms that caused the revision surgery were eliminated in all cases. None of these eyes has lost IOP control, none has required repeat trabeculectomy, and only 2 of the 32 (6%) require topical glaucoma medication. More than one revision procedure was required in 8 of 32 (25%) eyes. CONCLUSIONS: Surgical bleb revisions for complications after trabeculectomy surgery are safe and effective. Bleb reduction for large, symptomatic blebs or bleb repair for leaking blebs and hypotony did not lead to loss of IOP control.     

Late needle revision of failed filtering bleb with adjunctive Mitomycin C

A 61-year-old man presented to our hospital with right eye pain and headache off and on for 1 month. He had twice trabeculectomy in the right eye 25 years ago without using antiglaucoma agents. Snellen visual acuity (VA) was 20/400 and intraocular pressure (IOP) was 52 mm Hg in his right eye. The slit-lamp examination of his right eye revealed corneal microcystic edema and two blebs were noted. The nasal upper bleb had thinner wall with obvious focal underlying uvea dark color and temporal upper bleb had relative thicker wall. Both blebs showed low lying and high vascularity. No pupillary block was present. Considering the risks of repeat trabeculectomy and drainage implant, needle revision was done on the temporal upper bleb.A mixture of lidocaine and mitomycin C (MMC) was prepared for a final MMC concentration of 0.07 mg/ml. After 15 minutes of subconjunctival injection of lidocaine-MMC mixture, the needle revision was done to disrupt any episcleral and scleral fibrosis. Restoration of aqueous drainage was considered to be the end point when the bleb height was restored. The right eye VA was 20/100 on postoperatively Day 1 and IOP was 8 mm Hg. The only minor complication was subconjunctival hemorrhage. The IOP was around 10-15 mm Hg without antiglaucoma agent during a 6-month follow-up. The temporal upper bleb remained moderate height without hypervascularity or cystic change and no corneal edema was noted.Bleb needling with adjunctive MMC is simple and safe. It should be considered in the management of failing or failed filtration blebs.     

Epiconjunctival Mitomycin-C Application for Early Failing Filtering Blebs

Abstract

Purpose: To evaluate the effectiveness of epiconjunctival Mitomycin-C (MMC) application in early failing filtering blebs. Design: Interventional case series. Participants: Patients with failing blebs and raised intraocular pressure (IOP) in the early (two weeks to one month) postoperative period following glaucoma filtering surgery. Methods: A retrospective analysis of records of failed blebs was done for the period of April 2011-March 2012. Patients who were subjected to three applications of MMC (0.04%) applied over the conjunctiva directly over the bleb at baseline (visit1), one week (visit 2) and at one month (visit 3) were included. Bleb characteristics were graded in a blinded fashion by one independent ophthalmologist, while IOP during follow-up visits were analyzed. Main Outcome Measures: Intraocular pressure, need for additional measure, or medications and bleb characteristics as graded by Indiana classification. Results: Ten eyes of nine patients with failing blebs received topical MMC, including included eight males and one female with a mean age of 52?±?18 years (trabeculectomy:combined surgery?=?5:5). Complete success was seen in eight of 10 eyes with a final mean IOP of 14?±?2.9?mm Hg at three months. Excluding the two eyes that required medications, IOP reduction of 9%–42% was seen at visit 2, 16–57% IOP reduction at visit 3, and 16–56% at three months’ follow-up. Of eight eyes, all eyes showed decrease in vascularity of the blebs, p?<?0.001. While the height of the blebs did not show significant increase, all had increase in the avascular area of the bleb. One eye developed spontaneously resolving adenoviral conjunctivitis without any sequelae. Conclusion: Three applications of epiconjunctival MMC may be a safe alternative for salvaging failing blebs in the early postoperative period. This may help maximize anti-fibrotic effect of MMC while minimizing complications by limiting the area of contact.     

Morphology of functioning trabeculectomy blebs using anterior segment optical coherence tomography

Purpose:

To image trabeculectomy blebs using anterior segment optical coherence tomography (AS-OCT), and to correlate the bleb morphologic features at one month postoperatively with bleb function at six months.

Materials and Methods:

This prospective, observational study included 56 eyes undergoing trabeculectomy with MMC, followed up for minimum of six months. Postoperatively, bleb imaging was done using AS-OCT at one and six month. Bleb morphology was assessed for bleb wall reflectivity, bleb pattern in multiform reflectivity, visibility of drainage route and presence of hyper-reflectivity area. Bleb function was considered successful if IOP was <18 mmHg without medication at six month. Bleb morphology one month postoperatively was correlated with bleb function at six months.

Results:

At six months successful bleb function was noted in 44 (81.5%) eyes. Morphology of bleb at one month showed uniform bleb wall reflectivity in 6 eyes (11%) and multiform wall reflectivity in 48 eyes (89%). In eyes with multiform wall reflectivity, microcysts with multiple layers was seen in 26 eyes (48%), microcysts with subconjunctival separation in 12 eyes (22%) and only microcyst in 10 eyes (19%). When bleb features at one month were correlated with the bleb function at six months, logistic regression analysis revealed that blebs with multiform reflectivity with multiple internal layers with microcysts were associated with higher chances of success (P < 0.001).

Conclusion:

AS-OCT demonstrated early bleb morphological features that may be used to predict the functioning of a bleb. Multiform bleb wall reflectivity with a pattern of multiple internal layers and microcysts was associated with increased chances of success of a bleb.     

Intraoperative mitomycin-C without conjunctival and Tenon's capsule touch in primary trabeculectomy

OBJECTIVE: To verify whether intraoperative mitomycin C (MMC) without conjunctival and Tenon's touch is effective in inhibiting the development of thin, avascular blebs in eyes undergoing primary trabeculectomy. DESIGN: Noncomparative, interventional study. PARTICIPANTS: Fifteen eyes of 15 consecutive patients undergoing primary trabeculectomy. INTERVENTION: All eyes underwent trabeculectomy with intraoperative MMC (0.25 mg/ml for 3 minutes) without either conjunctival or Tenon's touch. Patients were examined 1 month, 3 months, 6 months, and 12 months after surgery. Intraocular pressure (IOP) and number of medications were evaluated at each examination. The appearance of the bleb was classified at the last examination into one of three groups: flat and vascularized; elevated but not avascular; or elevated, thin, and avascular. MAIN OUTCOME MEASURES: Intraocular pressure, number of antiglaucoma medications, and appearance of the bleb. RESULTS: Preoperative mean IOP was 30.57 +/- 10.92 mmHG: Statistically significant IOP reductions were observed 1 month, 3 months, 6 months, and 1 year after surgery (P < 0.01). Twelve months after surgery, the mean IOP was 14.92 +/- 6.53 mmHG: Five eyes (33.3%) showed an IOP less than 15 mmHg without antiglaucoma medication at the 12-month examination. The bleb was considered elevated, thin, and avascular in 12 of 15 eyes (80%) at the end of follow-up. CONCLUSIONS: Intraoperative MMC at 0.25 mg/ml for 3 minutes without either conjunctival or Tenon's touch was not effective in eliminating the development of thin, avascular blebs in eyes undergoing primary trabeculectomy.     

薄壁囊状滤过泡的结膜瓣加固术

目的　探讨改良转移结膜瓣对矫正青光眼小梁切除术后薄壁囊状滤过泡的临床效果。方法　剪开滤过泡周围的结膜（保留原滤过泡）,游离转移上方或颞侧球结膜-筋膜组织,加固覆盖于经局部冷冻的变性囊状泡表面,转移结膜瓣的前缘固定缝合于周边角膜的槽状浅沟内。转移结膜瓣不够松弛时,在穹窿部做一减张性球结膜-筋膜组织切开。结果　46例（52只眼）术后随访6个月至4年,平均眼压由术前（4.25±1.33）mmHg（1mmHg=0.133kPa）提高至术后（12.98±5.70）mmHg,差异有显著性（t=3.26,P<0.01）。51只眼仍保留滤过功能,20只眼的结膜渗漏和6只眼的黄斑水肿消失,术后视力较术前有明显改善（χ     

Stratus optical coherence tomography study of filtering blebs after primary trabeculectomy with a fornix‐based conjunctival flap

Purpose: To investigate the relationship between filtering bleb function and Stratus optical coherence tomography (OCT) images. Methods: We studied 72 eyes of 65 consecutive patients who had a fornix‐based conjunctival flap in primary trabeculectomy with mitomycin C (MMC). Filtering blebs with various types of glaucoma were examined using Stratus OCT. Success rates were defined as intraocular pressure (IOP) ≤ 15 mmHg and IOP reduction ≥ 25% without medication or additional surgery. Success rates among classified groups were compared using Kaplan–Meier survival curves and the log‐rank test. Results: Blebs were classified into three different categories on the basis of the following Stratus OCT patterns: cystoid type (multiple cysts inside the bleb; 17 eyes), diffuse type (low to high reflective areas that were mixed inside the bleb; 31 eyes) and layer type (medium to high reflective layer inside the bleb; 24 eyes). Success rates in the cystoid‐, diffuse‐ and layer‐type blebs were 94%, 97% and 75% (P = 0.02), respectively. Conclusion: In trabeculectomy with MMC and a fornix‐based conjunctival flap, there is a significant association between the success rates and the postoperative Stratus OCT findings of filtering blebs.     

Correlation between the early morphological appearance of filtering blebs and outcome of trabeculectomy with mitomycin C

PURPOSE: To correlate the morphologic appearance of filtering blebs in the early postoperative period with the outcome of trabeculectomy with mitomycin C (MMC) during the first postoperative year. PATIENTS AND METHODS: In a prospective study, the morphologic appearance of filtering blebs after primary trabeculectomy with adjunctive MMC (0.1 mg/ml for 5 minutes intra-operatively) was classified; 49 eyes of 49 patients were examined preoperatively, 1 and 3 days, 1 and 2 weeks, 1, 3, 6, and 12 months postoperatively. Status of filtering bleb, intraocular pressure (IOP), and number of medications were recorded. RESULTS: One year after surgery all patients had IOP < or = 21; 6 patients received antiglaucoma medication. One eye required needling of the filtering bleb because of encapsulation. During the first postoperative year, eyes with conjunctival subepithelial micro cysts, observed in the first and the second postoperative week, had significantly lower mean IOP, than eyes without (11.1 mm Hg vs. 13.9 mm Hg; p:0.0043, ANOVA). Eyes with corkscrew vessels, observed in the first and the second postoperative week, had significantly higher mean IOP, than eyes without during the first postoperative year (13.4 mm Hg vs. 11.7 mm Hg; p:0.0141, ANOVA). CONCLUSION: Classification of filtering blebs after trabeculectomy with MMC may help to disclose patients with an increased failure risk.     

Midterm follow-up of necrotic bleb excision and advancement of the fornical conjunctiva

Mitomycin C has improved the success rate of glaucoma filtering surgery in patients at high risk for surgical failure. However chronic hypotony is marked by decreased vision and a late-onset leaking bleb after filtration surgery using mitomycin C. Bleb excision and conjunctival advancement is the method of choice to repair bleb leakage and chronic hypotony. Five eyes from five patients were received glaucoma filtration surgery with topical mitomycin C. All of the patients' blebs were avascular and transparent. The reasons for bleb excision were two spontaneous bleb leaks, two traumatic bleb leaks and one case of severe irritation. The mean follow-up period was 18.4 +/- 8.3 months (ten to 29 months). Cataract surgery was combined in one eye. Postoperative intraocular pressure (IOP) increased from 2.3 +/- 1.5 mmHg to 9.5 +/- 3.7 mmHg at nine months postoperatively in four eyes. It went from 28 mmHg to 40 mmHg in one patient with uveitis, for whom a second trabeculectomy with mitomycin C; 0.4 mg/ml for 3 minutes, was performed. After surgery, IOP decreased to 4 mmHg in three months. Postoperative visual acuity improved four snellen lines in three eyes. A partially avascular bleb recurred in three eyes, a corneal bleb in one eye and blepharoptosis, which disappeared spontaneously at four months postoperatively, in one eye. Necrotic bleb excision and advancement of fornical conjunctiva were useful methods to increase IOP and to improve visual acuity for the patient experiencing irritation symptoms, and for leaking blebs, and hypotonic maculopathy.     

Cystic bleb formation and related complications in limbus- versus fornix-based conjunctival flaps in pediatric and young adult trabeculectomy with mitomycin C

OBJECTIVE: Comparison of fornix- and limbus-based conjunctival flaps with respect to cystic bleb-related complications of trabeculectomy with high-dose mitomycin C (MMC) in pediatric and young adult glaucoma. DESIGN: Retrospective nonrandomized comparative interventional case series. PARTICIPANTS: Thirty-seven patients. METHODS: Identification of patients aged <30 years from operating theater records from 1995 and 1996 of the Moorfields Pediatric Glaucoma Service who had trabeculectomy with an MMC concentration of >/=0.4 mg/ml. Over a 2-year period, 37 consecutive operations matching these criteria were performed by a single surgeon: 20 with a limbus-based flap and 17 with a fornix-based flap. Except for the conjunctival incision and associated alteration in antimetabolite application and wound closure, the surgical technique was not significantly different between the groups. MAIN OUTCOME MEASURES: Bleb evolution and complications. RESULTS: The age at time of surgery, MMC concentration, history of one or more previous surgeries, and follow-up were similar in the 2 groups. The risk of cystic bleb formation was greater in the limbus-based flap group (90% in the limbus-based group vs. 29% in the fornix-based group; P<0.001). Late hypotony and bleb-related ocular infection were more common in the limbus-based flap group (P<0.05) and occurred earlier. There were four episodes of bleb-related infection (20%) in the limbus-based group (three of these [15%] were bleb-related endophthalmitis) and none in the fornix-based group. CONCLUSIONS: In pediatric and young adult trabeculectomy with high doses of MMC, limbus-based flaps may be more likely to develop serious bleb-related complications and may develop these earlier than fornix-based flaps. The higher rates of complications could be attributable to the differences in bleb morphology, with limbus-based flap cases more likely to develop cystic blebs.     

Comparison of low-dose intraoperative mitomycin-C vs 5-fluorouracil in primary glaucoma surgery: a pilot study

BACKGROUND AND OBJECTIVE: This study was undertaken to compare the efficacy and safety of low-dose intraoperative application of mitomycin-C (MMC) with that of 5-fluorouracil (5-FU) in primary trabeculectomy. PATIENTS AND METHODS: A non-randomized prospective study was performed between August 1994 and November 1995. Thirty-two eyes of 16 consecutive patients who underwent trabeculectomy for uncontrolled glaucoma of various causes form the study group. The mean age was 46.8 +/- 9.9 years. The first eye received MMC (0.2, 0.4 mg/ml), fellow eye received 5-FU (50 mg/ml), for 1 minute intraoperatively. Bleb characteristics and intraocular pressure (IOP) control were analyzed. Success of surgery based on IOP control was measured by 3 different criteria: IOP less than 21 mm Hg; IOP less than 21 mm Hg with more than 30% reduction; and IOP less than 16 mm Hg with more than 30% reduction. RESULTS: Mean preoperative IOP was 31.4 +/-12.7 mm Hg in MMC group and 27.8+/- 8.8 mm Hg in 5-FU group. Mean follow-up in MMC group was 16.12 +/- 8.17 months; in 5-FU group 13.37 +/- 8.19 months. At last follow-up all 5-FU blebs were nonischemic, while 4 eyes in the MMC group showed nonischemic blebs, and 12 eyes had ischemic blebs. There was no statistically significant difference between MMC group and 5-FU group success rates with all 3 criteria. Success rates were: IOP less than 21 mm Hg; 100% in both groups; IOP less than 21 mm Hg with more than 30% reduction; MMC group 93.8%, 5-FU group 75%; less than 16 mm Hg with more than 30% reduction; MMC group 87.5%, 5-FU group 68.8%. CONCLUSIONS: Low-dose intraoperative MMC and 5-FU can provide control of IOP in primary trabeculectomy, 5-FU group showed more non-ischemic blebs.     

Results of medical management and mitomycin C-augmented excisional bleb revision for encapsulated filtering blebs

BACKGROUND AND OBJECTIVE: To assess the outcome of medical management and mitomycin C (MMC)-augmented excisional bleb revision (EBR) for encapsulated filtering blebs. PATIENTS AND METHODS: The author conducted a retrospective study of 503 patients who had undergone trabeculectomy performed over a 5 year period, followed up for at least one year, in order to identify the encapsulated filtering blebs. Mitomycin C-augmented (0.4mg/ml for 3 minutes) EBR was performed in cases of failed medical therapy for managing encapsulated blebs consisting of antiglaucoma medications, topical steroids, and digital compression. RESULTS: An encapsulated bleb developed in 18 eyes (3.6%) of 503 patients. Identification of bleb encapsulation occurred at a mean follow-up time of 24.2 +/- 10.4 days after surgery. The mean intraocular pressure (IOP) at that point was 30.4 +/- 11.7 mmHg in the affected eyes. Fifteen (83.3%) of 18 eyes responded to conservative management and 3 eyes (16.7%) required MMC augmented EBR. The mean IOP reduced from 30.4 +/- 11.7 mmHg to 14.2 +/- 4.2 mmHg after a mean follow-up of 37.6 +/- 11.4 months in the conservative management group, while it reduced from 37.3 +/- 23.4 mmHg to 12.0 +/- 4.4 mmHg after a mean follow-up of 42 +/- 6 months in the surgically treated group. None of the surgically treated eyes developed MMC-related complications. CONCLUSION: Conservative management is very effective in the treatment of encapsulated filtering blebs. The intraoperative use of MMC is a safe and effective adjunct in EBR in cases where conservative management has failed.     

小梁切除术中分别应用丝裂霉素C、5-氟尿嘧啶及生物羊膜的比较研究

目的比较原发性闭角性青光眼在初次小梁切除术中分别应用丝裂霉素C（MMC）、5-氟尿嘧啶（5-FU）或生物羊膜的疗效及并发症。方法急慢性闭角型青光眼41例（49只眼）,随机分为3组,做以角膜缘为基底的结膜瓣。应用抗代谢药物者,在完成板层巩膜瓣后接受结膜瓣下放置浸渍浓度为0.2 mg/ml的MMC棉片3min,或25 mg/ml的5-Fu棉片5 min,取出后用200 ml生理盐水冲洗结膜下及巩膜瓣下。应用生物羊膜者,在巩膜瓣下及结膜瓣下分别置单层羊膜。其他步骤同常规小梁切除术。结果随访半年以上,3组病例在眼压控制及手术成功率上均未见显著差异。MMC组滤过泡以微囊型为主（68.8%）;5-Fu及羊膜组以弥漫扁平型占优（分别为53.3%和61%）,但羊膜组较易发生包裹型滤泡倾向。MMC组的并发症发生率较其他两组高,主要为浅前房、结膜瓣渗漏、低眼压和黄斑水肿。结论三种方法均可应用于首次小梁切除患者,但需注意应用MMC者并发症较多;使用羊膜者需注意滤过泡的无功能化。     

Morphologic classification of filtering blebs after glaucoma filtration surgery: the Indiana Bleb Appearance Grading Scale

PURPOSE: To establish a new classification system for filtering blebs according to clinical morphologic parameters. The purpose of this classification system is to provide a uniform and objective assessment of bleb appearance and establish a framework system through which outcomes of filtration surgery may be better correlated to clinical morphology. MATERIALS AND METHODS: The Indiana Bleb Appearance Grading Scale contains a set of photographic standards illustrating a range of filtering bleb morphology selected from the slide library of the Glaucoma Service at the Indiana University Department of Ophthalmology. These standards consist of slit lamp images for grading bleb height, extent, vascularity, and leakage with the Seidel test. For grading, the morphologic appearance of the filtration bleb is assessed relative to the standard images for the 4 parameters and scored accordingly. Fifty-one clinical bleb photographs were evaluated and scored by 3 glaucoma subspecialists in a masked fashion according to the scale. RESULTS: For all of the grading scales, high interobserver agreement was found using the scale to classify the appearance of filtering blebs (height +0.76; extent +0.78; vascularity +0.90, interclass correlation coefficient for consistency using a 2-way mixed effect model). CONCLUSION: The Indiana Bleb Appearance Grading Scale is a simple, reproducible, yet comprehensive system for classifying the morphologic slit lamp appearance of filtration blebs.     

Prognostic outcome of leaking filtering blebs reconstruction with rotational conjunctival flaps

PURPOSE: Late bleb leaks may follow months to years after filtering surgery especially with the use of antimetabolites. Complications related to beb leaks may lead to a decrease in visual acuity through complicated hypotony or ocular infection. Our retrospective study reports the anatomical and functional results of bleb reconstruction involving the resection of the bleb associated with the covering of the trabeculectomy site with a rotational conjunctival flap. MATERIAL: and methods: Twelve eyes of eleven patients with filtering bleb leaks occurring 3 months to 5 years after successful trabeculectomy (58.3% with adjunct of antimetabolites) underwent bleb surgical reconstruction between november 1995 and June 1999 and were followed until March 2000. Surgical bleb reconstruction was indicated because of persistent or a recurring bleb leak despite conservative medical treatment and blood bleb injections in seven cases. Complications associated with bleb leaks were chronical hypotony (9 cases), athalamy (1 case), hypotony maculopathy (1 case), and endophtalmitis with athalamy (1 case). Three patients had normal IOP but a bleb leak responsible for epiphora. All eyes were treated surgically through bleb excision and conjunctival closure was performed by rotational conjunctival flap. RESULTS: Mean (+/- SD) preoperative IOP was 5.1+/-3.5mmHg (range: 2 to 14mmHg). Mean (+/- SD) postoperative IOP evaluated before any other operation for uncontrolled IOP was 12.7+/-3.1mmHg (range: 6 to 15mmHg). Mean follow-up was 26.7+/-16.9 months (range: 9 to 64 months). All the complications related to the bleb leak resolved after bleb reconstruction. Surgery definively stopped the leak in 10 cases (83.3%) and allowed IOP control without treatment in 50.0% of the cases. Chronic recurring bleb leaks without hypotony occurred in two eyes and required surgery with conjunctival graft which led to a refractory increase in IOP responsible for loss of vision in one case. CONCLUSION: Bleb resection associated with the covering of the trabeculectomy site with a rotational conjunctival flap is a safe and effective procedure for the treatment of a late bleb leak and its complications. In most of the cases (83.3%), long-term IOP control can be expected without, medical treatment in 50% of the cases. Patients must be aware of the possibility of a recurring Seidel; however, the incidence of this complication remains low.     

Filtering bleb modification with a THC:YAG (Holmium) laser

OBJECTIVE: To present a method for remodeling oversized blebs using the THC:YAG laser and describe its use in treating hypotony and bleb leaks. METHODS: Retrospective medical record review of 13 patients who underwent holmium laser bleb revision. RESULTS: Thirteen eyes of 13 patients were analyzed. All the patients had an oversized bleb and 2 patients presented an associated late-onset leaking bleb. Mean preoperative IOP was 4.1 mm Hg. THC:YAG laser energy was applied to the bleb to remodel and/or close the leak. After a mean follow up of 17.3 months, the mean IOP was 7.84 mm Hg +/- 2.3. Postsurgery complications included hyphema and the inadvertent rupture of a conjunctival microcyst. Visual acuity improved in 9 of the eyes and remained stable in 4 of the eyes. CONCLUSION: The THC:YAG laser can be used effectively to sculpt large blebs, reduce symptoms associated with large blebs, increase IOP in hypotonous eyes, and under specific circumstances, close bleb leaks.     

Partial Tenon's capsule resection with adjunctive mitomycin C in Ahmed glaucoma valve implant surgery

AIM: To verify if partial intraoperative Tenon's capsule resection (PTCR) with adjunctive mitomycin C is effective in developing thin, avascular blebs in eyes undergoing Ahmed glaucoma valve insertion, and to assess the efficacy and safety of this procedure. METHODS: A multicentre, prospective, alternating case assignment, investigator unmasked, parallel group, comparative interventional study was conducted in four Latin American countries (Argentina, Brazil, Colombia, and Peru). Ahmed glaucoma valve implant insertion with PTCR (group A) and without PCTR (group B) was performed in neovascular glaucomatous eyes without previous surgery. Adjunctive mitomycin C (MMC) was used in both groups. Patients were examined 1 day, 10 days, 1 month, 2 months, 3 months, 6 months, and 1 year following the surgery. Intraocular pressure (IOP) and the appearance of the bleb were evaluated at each examination. Appearance of the bleb was classified at both the 1 month mark and last examinations into one of three groups: flat and vascularised; elevated avascular; or elevated and not avascular. RESULTS: 92 eyes from 92 patients were included in the study. The preoperative mean IOP was 50.0 (SD 10.5) mm Hg in group A and 48.4 (11.7) in group B (p>0.05). Statistically significant IOP reductions were observed at all periods of follow up. 12 months after surgery, the mean IOP was 17.2 (5.0) mm Hg in group A and 18.3 (8.7) mm Hg in group B (p>0.05). A hypertensive phase occurred in 40.0% in group A and in 46.8% in group B (p>0.05). At the 1 month and the final follow up, the blebs in all eyes were considered elevated and not avascular. The success rate (IOP0.05). Overall, 74.2% of the patients achieved an IOP 相似文献   

Intrastromal diathermal keratostomy: a new micropenetrating clear-cornea glaucoma procedure

PURPOSE: The filtering intrastromal diathermal keratostomy (IDK) was developed to comply with the call for a low postoperative intraocular pressure (IOP) and a bleb morphology without a thin, cystic appearance. PATIENTS AND METHODS: A diathermal microkeratostomy (150 to 200 microm) was created into the anterior chamber, anterior to the Schwalbe line through the floor of a surgical corneoscleral tunnel incision into the subconjunctival space. A newly developed, bipolar diathermal microneedle was used to create the keratostomy, replacing the Holmium laser used previously. Subconjunctival injections of 3 microg mitomycin C were used in each eye 1 week before the IDK to obtain maximum antiproliferative effect at the time of the operation. Nine patients (10 eyes) with complicated, refractory primary and secondary open-angle glaucoma are discussed. RESULTS: Histologic examination of the IDK and clinical postoperative ultrasound biomicroscopy showed an optimal appearance of the diathermal microkeratostomy. After 34 months (range 24 to 42 mo) the mean IOP was 11 mm Hg (SD+/-3, range 6 to 16) without medication in all 10 eyes. IDK revision with internal needling of postoperative subconjunctival fibrosis through the tunnel incision was performed in 5 eyes after an average of 3 months (range 0.2 to 7 mo). After 33 months (range 19 to 38 mo), the postrevision mean IOP was 10 mm Hg (SD+/-2, range 8 to 14) without medication in all 5 eyes. All 10 eyes showed noncystic diffuse blebs with optimal spongy subepithelial morphology: in 2 eyes the blebs were totally avascular and in 8 eyes they were relatively avascular. CONCLUSIONS: The preliminary results of the new clear-cornea IDK seem promising because of postoperative IOP of about 10 mm Hg despite a low dose of mitomycin C and noncystic bleb morphology.