Biodegradable collagen matrix implant vs mitomycin-C as an adjuvant in trabeculectomy: a 24-month, randomized clinical trial

Anterior segment optical coherence tomography imaging of conjunctival filtering blebs after glaucoma surgery

Time domain (TD) and spectral domain (SD) optical coherence tomography (OCT) are cross-sectional, noncontact, high-resolution diagnostic modalities for posterior and anterior segment (AS) imaging. The AS-OCT provides tomographic imaging of the cornea, iris, lens, and anterior chamber (AC) angle in several ophthalmic diseases. In glaucoma, AS-OCT is utilized to evaluate the morphology of AS structures involved in the pathogenesis of the disease, to obtain morphometric measures of the AC, to evaluate the suitability for laser or surgical approaches, and to assess modifications after treatment. In patients undergoing surgery, AS-OCT is crucial in the evaluation of the filtering bleb functionality, permitting a combined qualitative and quantitative analysis. In this field, AS-OCT may help clinicians in distinguishing between functioning and nonfunctioning blebs by classifying their macroscopic morphology, describing bleb-wall features, bleb cavity, and scleral opening. This information is critical in recognizing signs of filtration failure earlier than the clinical approach and in planning the appropriate timing for management procedures in failing blebs. In this review, we summarize the applications of AS-OCT in the conjunctival bleb assessment.

Wound Healing Modulation in Glaucoma Filtration Surgery- Conventional Practices and New Perspectives: Antivascular Endothelial Growth Factor and Novel Agents (Part II)

Glaucoma filtration surgery is regularly performed for the treatment of glaucoma and trabeculectomy is often regarded as the ‘gold standard' glaucoma operation. The biggest risk of failure of the operation is bleb scarring. The advent of antifibrotic agents, such as mitomycin C (MMC) and 5-fluorouracil (5FU) has vastly prolonged the longevity of the bleb, but concerns remain regarding the potential increase in postoperative complications. More selective therapeutic targets have therefore been explored. One of these is vascular endothelial growth factor (VEGF) inhibition. VEGF inhibition has a role not only in subconjunctival angiogenesis inhibition but also it has direct anti-fibrotic properties. Newer pharmacological compounds and materials have also been developed in recent years in attempt to modulate the wound healing in different ways after glaucoma surgery. These include physical barriers to scarring and vehicles for sustained release of pharmacological agents, and early promising results have been demonstrated. This two-part review will provide a discussion of the application of anti-fibrotic agents in glaucoma filtration surgery and evaluate the newer agents that have been developed.

How to cite this article: Fan Gaskin JC, Nguyen DQ, Ang GS, O'Connor J, Crowston JG. Wound Healing Modulation in Glau coma Filtration Surgery–Conventional Practices and New Pers pectives: Antivascular Endothelial Growth Factor and Novel Agents (Part II). J Curr Glaucoma Pract 2014;8(2):46-53.

Efficacy and safety of collagen matrix implants in phacotrabeculectomy and comparison with mitomycin C augmented phacotrabeculectomy at 1 year

BACKGROUND

To assess the efficacy and safety of collagen matrix implant (Ologen) in phacotrabeculectomy.

DESIGN

Prospective, non-randomized, comparative study.

PARTICIPANTS

Sixty-six Asian patients.

METHODS

Thirty three consecutive patients underwent phacotrabeculectomy with Ologen implant and intraocular lens implantation, and 33 subjects recruited as controls underwent surgery with mitomycin C augmentation.

MAIN OUTCOME MEASURES

The primary outcome measure was postoperative intraocular pressure at month 12. Additional postoperative treatments, such as bleb needling, and adverse events were secondary outcomes.

RESULTS

The overall percentage reduction in intraocular pressure was 13% (95% confidence interval 6.7-19.2) in the Ologen group and 26% (95% confidence interval 14.8-37.9) in the mitomycin C group (P = 0.05). At 1 year after surgery (after adjusting for baseline differences), intraocular pressure decreased by 4.2 mmHg (95% confidence interval 2.8-5.6 mmHg) and 5.6 mmHg (95% confidence interval 4.2-7.0 mmHg), respectively (P = 0.16). Needling with 5-fluorouracil was required more often in the Ologen group (39% vs. 6%; P = 0.003). There was similar frequency (<10%) of adverse events in both groups, and there were no complications directly related to the Ologen implant. The blebs in the mitomycin C group had greater central area (P = 0.005), maximal area (P = 0.01) and height (P = 0.005), and were less vascular (P = 0.023) than the Ologen blebs.

CONCLUSIONS

At 1 year, the overall performance of Ologen in combined phacotrabeculectomy was suboptimal compared with combined surgery with mitomycin C. Eyes in the Ologen group required more frequent bleb needling procedures.

Ologen implant versus mitomycin C for trabeculectomy: a systematic review and meta-analysis

OBJECTIVE

To evaluate the application of the Ologen implant compared to mitomycin C (MMC) on the outcome of trabeculectomy and to examine the balance of risks and benefits.

METHODS

A systematic literature search (Pubmed, Embase, the Cochrane Library, and the Chinese Biomedicine Database) was performed. Randomized controlled trials comparing the Ologen implant with MMC in trabeculectomy were selected. The efficacy measures were the weighted mean differences (WMDs) for the intraocular pressure reduction (IOPR), the reduction in glaucoma medications, and the relative risks (RRs) for success rates. The tolerability measures were RRs for adverse events. The pooled effects were calculated using the random-effects model.

RESULTS

Seven randomized controlled trials including 227 eyes were included in this meta-analysis. The WMDs of the IOPR comparing the Ologen group with the MMC group were -2.98 (95% Cl: -5.07 to -0.89) at one month, -1.41 (-3.72 to 0.91) at three months, -1.69 (-3.68 to 0.30) at six months, -1.94 (-3.88 to 0.01) at 12 months, and 0.65 (-2.17 to 0.47) at 24 months. There was no statistically significance except at one and 12 months after surgery. No significant difference in the reduction in glaucoma medications or complete and qualified success rates were found. The rates of adverse events also did not differ significantly between Ologen and MMC.

CONCLUSIONS

The Ologen implant is comparable with MMC for trabeculectomy in IOP-lowering efficacy, reduction in the number of glaucoma medications, success rates, and tolerability. However, the results should be interpreted cautiously since relevant evidence is still limited, although it is accumulating. Further large-scale, well-designed randomized controlled trials are urgently needed.

[Modern filtration surgery. An update]

Preoperative treatment with steroids and nonsteroidal anti-inflammatory drugs increases the success of filtration surgery. Surgery with the patient under subconjunctival anesthesia is safe. Intraoperative application of mitomycin C is state of the art and enhances success rates. Perioperative use of bevacizumab seems to attenuate postoperative fibrosis. Postoperative hypotension is avoided by stable fixation of the scleral flap followed by stepwise controlled suturelysis or release. Transconjunctival flap suturing allows fast and simple treatment of overfiltration. The shorter the time lag between trabeculectomy and subsequent cataract surgery the higher the probability of bleb failure will be. The number of antiglaucomatous drugs and severity of glaucomatous damage before surgery correlate with the probability of failure and blindness.

Secondary subconjunctival implantation of a biodegradable collagen-glycosaminoglycan matrix to treat ocular hypotony following trabeculectomy with mitomycin C

AIM

Biodegradable collagen glycosaminoglycan matrices (CGM) have been introduced to glaucoma filtration surgery in order to prevent scarring of the filtering bleb. In this retrospective case series, we describe a new surgical concept for treating symptomatic ocular hypotony following filtration surgery with mitomycin C by a secondary subconjunctival implantation of a CGM.

METHODS

Depending on bleb morphology, a CGM implant with a diameter of 6 or 12 mm was placed subconjunctivally on the scleral flap in 12 eyes displaying symptomatic ocular hypotony with (n=2) or without (n=10) bleb leakage. Median period between trabeculectomy and this intervention was 4.5 months (range, 1-72 months).

RESULTS

Mean intraocular pressure significantly increased from 4.4±1.4 mm Hg to 9.9±2.8 mm Hg (p<0.0001) over a median follow-up of 6 months (range, 2-18 months). Mean visual acuity improved significantly (p=0.0012). Postoperative complications included implant re-exposure in one eye and persistent choroidal detachment requiring resurgery in another eye.

CONCLUSIONS

Subconjunctival implantation of CGM may present an additional surgical tool in the treatment of symptomatic ocular hypotony after filtering surgery. The mechanism of action may be counter-pressure to the scleral flap and secondary wound healing around the CGM scaffold. Long-term observations are needed to fully evaluate this new surgical concept.

New trends in glaucoma risk, diagnosis & management

Recent advances have seen a surge of new ideas and technologies to aid in the detection, treatment and further understanding of glaucoma. These technologies and advances are discussed to provide information on risk-factors, diagnosis and treatment. Glaucoma has never before seen such an advance in research and therapies coming forward in to the clinical workplace. It is an exciting time for physicians and researchers alike and over the next decade will certainly see advances in early detection, efficacious treatments and neuroprotection.

Collagen matrix implantation following pterygium excision: outcomes of a preliminary tested hypothesis

This study was conducted to evaluate the effect of collagen matrix implant on pterygium recurrence compared with a control group following pterygium removal surgery. Following informed consent, twenty eyes of 20 patients (females = 13, males = 7, aged 23-67 years) were randomly allocated into two equal groups. Pterygia of all patients were excised using the bare sclera technique; however, for patients in the intervention group a 1×2 mm collagen matrix graft (iGen™) was implanted subconjunctivally. Patients were followed up for recurrence and complications within six months. Results revealed that only two eyes in the control group and one eye in the intervention group developed recurrence (p=0.50); no dellen formation was observed. In conclusion, the use of biodegradable collagen matrix implants (iGen™) following pterygium excision seems to be associated with a lower risk of recurrence; however, the statistical difference between groups was not significant. Further studies with adequate sample size are recommended.

One Year of Glaucoma Research in Review: 2011 to 2012

PURPOSE

To provide the practicing clinical ophthalmologist with an update of pertinent glaucoma literature published over the past 12 months.

METHODS

The authors conducted a one year (July 1, 2011 to June 30, 2012) English language glaucoma literature search on Pubmed using the following terms: automated perimetry, optic nerve imaging, optical coherence tomography, glaucoma structure and function, intraocular pressure, central corneal thickness, medical therapy and compliance in glaucoma, glaucoma laser treatment, cataract extraction and intraocular pressure, secondary glaucoma, glaucoma surgery, pediatric glaucoma, molecular biology in glaucoma, and miscellaneous topics in glaucoma.

DESIGN

Literature review.

RESULTS

This review includes original and review articles that reflect novel aspects and updates in the field of glaucoma, while excluding letters to the editor, unpublished works, and abstracts.

CONCLUSIONS

This review is not meant to be all-inclusive-rather, it highlights literature that is most applicable to ophthalmologists in practice.