The Long-term Outcome of Primary "Bleb-sparing, Epithelial Exchange" in Dysfunctional Filtering Blebs

Outcomes of surgical bleb revision at a tertiary Singapore eye hospital

PURPOSE

To describe the outcomes of surgical bleb revisions from a tertiary glaucoma service in Singapore.

METHODS

One hundred and thirty-one eyes of 129 patients who underwent surgical bleb revisions at the Singapore National Eye Centre between 2007 and 2014 were included in the study. The indications for bleb revision were: bleb-related infection (BRI), early and late bleb leak, early and late overfiltration, and bleb dysesthesia. Regression analysis was applied to elucidate risk factors.

RESULTS

The mean age of the patients was 66 years, 62.6% were male, and 88.5% were Chinese. The majority of the eyes had primary glaucoma (79.4%). The mean interval from the initial trabeculectomy or phaco-trabeculectomy to the bleb revision was 58.8 months. The overall success rate was 69.5%. By Kaplan-Meier survival analysis, the overall cumulative success range fell from 78.6% to 49.1% over 10 years. Eyes with early bleb leak had lower surgical success compared to eyes with late bleb leak, early overfiltration and late overfiltration (P = 0.026, log-rank test). The IOP improved significantly post-operatively for eyes with BRI, early bleb leak, late bleb leak, early overfiltration and overfiltration (P < 0.05). Vision improved significantly in eyes with early overfiltration, but deteriorated in eyes with BRI (P < 0.05).

CONCLUSION

The overall success rate for surgical bleb revisions was good with complete resolution of the primary problem in the majority of cases. However, eyes with early bleb leak were less likely to have successful outcomes and should be monitored more closely post-operatively.

Intraoperative Optical Coherence Tomography-Guided Bleb-sparing Epithelial Exchange: A Modified Approach

With the advent of newer technologies, real-time anterior segment optical coherence tomography (OCT) integrated with the operating microscope has become possible. We are proposing the technique of bleb revision with greater precision under direct visualization of bleb anatomy and extent of tissue depth allowing better localization and easy maneuvering with lesser complications. In this surgical technique, bleb revision was performed using intraoperative real-time OCT incorporated in OPMI LUMERA 700 microscope. Live surgical and OCT view were seen on a common screen together. A moderately elevated, diffuse functional bleb was noted after three months of bleb revision in both cases with controlled intraocular pressure. Intraoperative OCT-guided bleb-sparing epithelial exchange is an adjunctive technique for bleb repair surgery with an increased precision of surgery which can reduce complications, minimize surgical time and maximize surgical outcome.

Does TRABECULECTOMY meet the 10-10-10 challenge in PACG, POAG, JOAG and Secondary glaucomas?

PURPOSE

Evaluation of the intraocular pressure (IOP) lowering efficacy of trabeculectomies over > 10 years and their ability to stabilize glaucomatous optic neuropathy.

METHODS

In total, 181 eyes (136 patients), which underwent trabeculectomy (10 min surgery) at least 10 years prior and were on regular follow-up, were evaluated. Qualified/complete success was taken as criteria A: IOP ≤ 12 mmHg, B: IOP ≤ 15 mmHg and C: IOP ≤ 18 mmHg, with all > 5 mmHg, with/without medications. Target IOP in advanced glaucoma is about 10 mmHg, therefore trabeculectomy 10-10-10 challenge!

RESULTS

The mean age of patients was 46.32 ± 11.50 years. Absolute success was 50.27%, 54.14% and 59.66% according to criteria A, B and C at last follow-up, while qualified success was 70.11%, 81.77% and 96.13%. An IOP of ≤ 12 mmHg was noted in 34, 64.15%, PACG eyes, 14, 73.68%, POAG, 15, 65.22%, JOAG and 64, 74.42%, secondary glaucoma eyes. The reduction in IOP overall was 64.83 ± 16.80% at last review and was 59.47 ± 16.07% in PACG, 62.40 ± 17.72% in POAG, 71.89 ± 8.50% in JOAG and 67.74 ± 18.10% in secondary glaucoma eyes. "Target" IOP was achieved in 97.29% of early glaucoma, 85.71% moderate glaucoma and 70% severe glaucoma eyes. 97.24% of patients were perimetrically stable. 2.21% of eyes post-trabeculectomy had a shallow anterior chamber needing surgical intervention. Visual acuity was maintained or better in 93.92% of patients, with a cataract surgery performed in 6.63% eyes. A repeat trabeculectomy was performed in 3.31% of eyes.

CONCLUSION

Trabeculectomy 10-10-10 is achievable in the long term, with few complications or repeat surgical interventions in the majority of POAG, PACG, JOAG and secondary glaucomas. Therefore, trabeculectomy should not be relegated to a last resort, but should be undertaken as soon as possible, if medical therapy is inadequate, unaffordable or compliance is an issue.

Clinical and ASOCT evaluations of 'bleb-sparing epithelial exchange' in paediatric and adult dysfunctional blebs over 5 years

PURPOSE

To evaluate the long-term outcome of 'bleb-sparing epithelial exchange' surgery for dysfunctional filtering blebs in paediatric and adult eyes.

METHODS

Patients who had undergone bleb revision ≥ 5 years back and were on regular follow-up were included. Age, ocular diagnosis, details of primary filtering surgery including mitomycin-C (MMC) usage, indication and year of bleb revision were recorded. After bleb revision, the mean intraocular pressure (IOP), glaucoma medications and best corrected visual acuity (BCVA) up to 5 years were noted. On last review, clinical details, bleb characteristics and swept source anterior segment tomographic (SSOCT) assessment of bleb were recorded. Comparative analysis of paediatric and adult eyes was performed.

MAIN OUTCOME MEASURES

Change in IOP and BCVA. 'Complete success' was defined as IOP ≥ 6 to ≤ 18mmHg without use of any topical glaucoma medications and 'Qualified success' when ≥ 1 topical glaucoma medication(s) was required.

RESULTS

A total of 51 eyes of 51 consecutive patients were studied, among which 22 were children. The mean duration between filtering surgery and bleb revision was 4.54 ± 1.53 years in paediatric and 6.48 ± 3.5 years in the adult group, p = 0.04. Children underwent trabeculotomy + trabeculectomy with 0.04% MMC, while adults underwent trabeculectomy with 0.02% MMC. The mean pre-revision IOP was 6.38 ± 2.80 and 6.51 ± 2.78 mmHg in the paediatric and adult group respectively, p = 0.86. At 3 months post-revision, it increased to 11.81 ± 3.48 and 12.75 ± 3.52 mmHg respectively (p < 0.001). At final review, mean IOP of paediatric group was 10.90 ± 2.59 and adult group was 11.86 ± 2.66 mmHg, p = 0.20. At 5 years, complete success was 68.18% and 72.41%, and qualified success was 31.87% and 27.59% in the former and latter group respectively, p = 0.49. No failures were seen. Kaplan-Meier probability at 5 years for IOP target ≤ 18, ≤ 15 and ≤ 12 in children was 95.45%, 63.64% and 50% and in adults 93.10%, 65.52% and 41.38% respectively. BCVA improved up to 1 year in paediatric group, with continued improvement in adults up to 3 years. SSOCT measured bleb height was 0.88 ± 0.37 and 1.32 ± 0.49mm in children versus adults (p = 0.006) and wall thickness, 0.35 ± 0.22 and 0.58 ± 0.24mm respectively, p = 0.008.

CONCLUSION

Bleb-sparing epithelial exchange is an equally safe and effective technique with good long-term success in both paediatric and adult dysfunctional blebs.

Identification and Characterization of Imaging Technique Errors and Artifacts Using Anterior-Segment OCT for Irido-Corneal Angle Evaluations in Glaucoma

PURPOSE

Anterior-segment OCT (AS-OCT) platforms provide noninvasive and quantifiable evaluations of anterior chamber angle (ACA) anatomy. Although these ACA measurements have been validated with high repeatability and reproducibility, there is a paucity of data previously published regarding the technique errors and artifacts (TEA) that may occur during imaging of the ACA. The purpose of this study was to report on the types and frequency of imaging TEA that are seen in ACA evaluation of a large cohort of patients with open-angle glaucoma.

DESIGN

Retrospective, cross-sectional design.

PARTICIPANTS

Images were obtained with AS-OCT from 5082 eyes of 2541 patients with glaucoma and were reviewed at the Doheny Image Reading Center (DIRC).

METHODS

Images had been captured using AS-OCT devices from 4 different manufacturers (Zeiss Cirrus [Oberkochen, Germany], Heidelberg Spectralis [Heidelberg, Germany], Optovue RTVue [Fremont, CA], or Zeiss Visante). All images were analyzed by 2 independent and certified DIRC image readers for angle opening distance under Schwalbe's line (SL-AOD), and then re-reviewed by a DIRC-certified principal investigator to adjudicate nonconsensus measurements. Images were defined to have TEA when image readers were unable to confidently measure the SL-AOD.

MAIN OUTCOME MEASURES

Type and frequency of TEA in the AS-OCT image.

RESULTS

Of 5082 eyes reviewed, 208 images (4.09%) were found to have TEA that restricted proper visualization of irido-corneal angle structures and measurements of SL-AOD. The most common TEA was that the image readers were unable to identify Schwalbe's line (74% of TEA images). Other common TEA included poor visualization of the anterior iris surface (15%), misaligned scan location (11%), irregular corneal irregularities (5%), and illumination-related pupillary abnormalities (4%).

CONCLUSIONS

This large-scale study presents the types and frequency of TEA found in AS-OCT-derived angle images. More than 95% of the images reviewed were usable for the quantification of irido-corneal angle measurements. Knowing the common types of TEA may help in enhancing the training of both human image readers and in the design of automated algorithms to improve image acquisition and image interpretation parameters. This will become especially useful as AS-OCT becomes more widely used in clinical practice for anterior chamber assessment.

Innovations in glaucoma surgery from Dr. Rajendra Prasad Centre for Ophthalmic Sciences

Trabeculectomy surgery is the current standard of care in glaucoma for achieving a low target intraocular pressure if medical therapy is not adequate. Augmentation of trabeculectomy with antimetabolites brought a revolutionary change in the long-term success rates of trabeculectomy, but along with it came a plethora of complications. There still is a big window for therapeutic innovations on this subject. The foremost target for these innovations is to modulate the wound healing response after glaucoma drainage surgery. Achieving the desired balance between long-term success of filtering blebs versus early failure due to scarring of blebs and hypotony due to dysfunctional filtering blebs poses a unique challenge to the ophthalmologists. Alternatives to trabeculectomy such as glaucoma drainage devices and minimally invasive glaucoma surgeries cannot solve the problem of glaucoma blindness in our country, mainly due to their unpredictable results and unfavorable cost-benefit ratio. In this article, we present a summary of our innovations in glaucoma surgery to advance patient care by making it more effective, safer, and economical.

Safety and efficacy of canaloplasty versus trabeculectomy in treatment of glaucoma

We assess the efficacy and safety of canaloplasty and trabeculectomy for treatment of glaucoma. We searched the China National Knowledge Infrastructure, PubMed, Web of Science, and WanFang databases for potentially eligible studies. Pooled risk ratio (RR) with 95% confidence interval (CI) was calculated using random- or fixed-effect models if appropriate. Eight studies were included for meta-analysis. There was no difference in intraocular pressure at 6 months (WMD = 0.97, 95%CI: -0.48-2.41). Intraocular pressure in canaloplasty group 12 months after operation was higher than in trabeculectomy group (WMD = 1.90, 95%CI: 0.12-3.69), P < 0.05). The canaloplasty group showed higher success rate than trabeculectomy group (RR = 0.86, 95%CI: 0.77-0.97). The canaloplasty group was more likely to have hyphema (RR = 2.96, 95%CI: 1.51-5.83), P < 0.05) than trabeculectomy group (RR = 0.24, 95, CI(0.06-0.89), P < 0.05]. The incidence of and hypotony and postoperative choroid abnormalities in canaloplasty group was significantly lower than that in trabeculectomy group (RR = 0.30, 95%CI: 0.11-0.83; RR = 0.24, 95%CI: 0.09-0.66), P < 0.05). Both trabeculectomy and canaloplasty can significantly reduce the intraocular pressure in glaucoma patients at 12 months after operation, trabeculectomy leads a more marked IOP decrease than canaloplasty at the cost of a higher complication rate and more demanding for postoperative care.