Intraoperative episcleral versus postoperative topical application of mitomycin-C for trabeculectomies

Reintervention rate in glaucoma filtering surgery: A systematic review and meta-analysis

PURPOSE

Reintervention rate is an important factor impacting on patients, surgeons, and society. To date, only a few studies have focused on this topic. For this reason, a systematic review and meta-analysis was undertaken to assess the reintervention rate after glaucoma filtering surgery.

MATERIALS AND METHODS

Prospective studies reporting the reintervention rate after glaucoma filtering surgery and with at least 12 months of follow-up were systematically searched on PubMed, Medline and Embase databases. The primary outcome was the total reintervention rate following surgery. Secondary outcomes were: the rate of manipulation, in-clinic and in-operating room reintervention; the reintervention rate for intraocular pressure (IOP) control and for complications; demographic, clinical and surgical variables associated with reintervention rate.

RESULTS

Ninety-three studies with a total of 8345 eyes were eligible. The total reintervention rate was 1.84 (95% CI 1.57-2.13), with a lower rate for Baerveldt (0.53, 95% CI 0.29-0.83) and Preserflo (0.60, 95% CI 0.15-1.29), and a higher rate for Xen (4.26, 95% CI 2.59-6.31). The manipulation rate was 0.99 (95% CI 0.77-1.23), the in-clinic reintervention rate was 0.08 (95% CI 0.05-0.12) and the in-operating room reintervention rate was 0.28 (95% CI 0.22-0.35). The reintervention rate for IOP control was 1.26 (95% CI 1.04-1.51) and the reintervention rate for complications was 0.27 (95% CI 0.21-0.35).

CONCLUSIONS

All types of surgery presented a total reintervention rate similar to the overall findings, except studies on Baerveldt and Preserflo Microshunt, with a lower rate, and Xen, with a higher rate. None of the variables evaluated were found to be directly associated with the explored outcomes.

Recognition, Diagnosis and Treatment of Chorioretinal Folds: Current Perspectives

Chorioretinal folds (CRFs) are undulations of the choroid and overlying Bruch’s membrane, retinal pigment epithelium and neurosensory retina. CRFs represent a clinical sign that is mandatory to investigate assuming their association with several ocular and extra-ocular disorders. Recent advances in retinal imaging have improved the characterization of CRFs. More importantly, retinal imaging may be useful to detect ocular complications secondary to chronic CRFs, including the development of choroidal neovascularization.

Hypotony Maculopathy: Clinical Presentation and Therapeutic Methods

Introduction

Hypotony maculopathy is ocular hypotony complicated by papilledema and/or folding of the retina and choroid in the posterior pole. Our objective was to examine the current literature regarding hypotony maculopathy and treatment methods.

Methods

A systematic review of the English-language literature was conducted by performing a broad search of PubMed from 1972 through 2015 using the keywords hypotony maculopathy and hypotony. Additional articles were identified from bibliographies of relevant articles.

Results

Hypotony maculopathy was infrequent before the introduction of antimetabolite agents in glaucoma-filtering surgery, and the incidence of this entity is now up to 20%. Risk factors for developing hypotony maculopathy include male gender, young age, myopia, and primary filtering surgery. Correctly identifying the etiology of hypotony is essential for successful treatment. Treatment of hypotony maculopathy includes procedures to elevate the intraocular pressure, thus reversing the collapse of the scleral wall and chorioretinal wrinkling.

Conclusion

This review discusses the definition, clinical presentation, pathophysiology, incidence and risk factors, prevention and treatment of hypotony maculopathy.

CSM enhances the filtration bleb survival in rabbit model of experimental glaucoma surgery

PURPOSE

The aim of this study is to investigate whether CS-g-MMCs conjugate (CSM) could be a new agent to prevent the post-operative fibrosis in a rabbit model of experimental glaucoma filtration surgery.

MATERIALS AND METHODS

In a randomized, controlled, masked-observer study, 40 New Zealand White rabbits underwent trabeculectomy in the right eyes and randomly received subconjunctival injection of phosphate buffered saline, chitosan (CS), CSM (100 µg/ml), CSM (200 µg/ml) or Mitomycin C (100 µg/ml). Bleb characteristics and anterior chamber depth were evaluated by slit-lamp examination. The animals were killed on day 14 and 28. Histopathology and immunohistochemistry were performed to determine the amount of the scarring and fibrosis. Ocular toxicity was assessed by histopathology and electron microscope.

RESULTS

We found that the five groups were similar with respect to intraocular pressure and anterior chamber depth. The medians for survival days were: 5.5, 8, 17.5, 28 and 16 in the PBS, CS, CSM100, CSM200 and MMC groups, respectively. Both the CSM200 and the MMC group showed a significantly larger bleb area than the CSM100, CS and the PBS group. Less scarring was seen on day 14 and 28 in CSM200 and MMC group than in the PBS, CS and CSM100 group by histology and immunohistochemistry assessment. No damages were found in the rabbit eyes in each group.

CONCLUSIONS

Subconjunctival injection of CSM postoperatively can improve the filtration bleb survival in the rabbit model. It can be a safe and effective antimetabolite in glaucoma surgery.

Moving the goal posts definitions of success after glaucoma surgery and their effect on reported outcome

PURPOSE

To determine (1) the extent to which the definition of success of glaucoma surgery varies in the literature and (2) the degree to which the reported outcome after trabeculectomy is affected by the criteria used to define success.

DESIGN

A systematic review of the literature and application of definitions to a retrospective cohort.

PARTICIPANTS

A cohort of 100 patients who previously underwent trabeculectomy.

METHODS

A literature search was performed of PubMed using the search term trabeculectomy for a 5-year period. Studies presenting original data relating to longitudinal intraocular pressure (IOP) control after glaucoma surgery were included. The definitions of success and failure used were documented for each publication. Each IOP-related definition of success was applied to a cohort of patients who previously underwent trabeculectomy. Success rates were derived for each published definition up to 36 months after surgery.

MAIN OUTCOME MEASURES

Intraocular pressure measured by Goldmann applanation tonometry.

RESULTS

From 100 publications meeting the inclusion criteria, 92 distinct IOP-related definitions of success were identified. Using these definitions, success rates for this series of 100 trabeculectomies varied between 36.0% and 98.0% after 3 years of follow-up.

CONCLUSIONS

Over a recent 5-year period, there were nearly as many different definitions of success after glaucoma surgery as publications on the subject. The definition used markedly affects the quoted success rate after trabeculectomy, making interpretation of and comparison between published results extremely difficult. Standardization of published outcome parameters after glaucoma surgery is essential to allow meaningful comparisons between different study reports.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Transconjunctival penetration of mitomycin C

Aims:

The study was performed to estimate transconjunctival penetration of mitomycin C (MMC) to Tenon′s tissue following application over the intact conjunctiva before routine trabeculectomy.

Settings and Design:

Institution-based case series.

Materials and Methods:

In 41 eyes of 41 patients, MMC (0.4 mg/ml for 3 min) was applied over the intact conjunctiva before beginning trabeculectomy. Tenon′s capsule directly beneath the site of application was excised during trabeculectomy and was homogenized, centrifuged and MMC concentrations were analyzed using high-performance liquid chromatography (HPLC).

Statistical Analysis Used:

Statistical analysis was performed using stata0 8.0 version software (STATA Corporation, Houston, TX, USA). In this study, P -values less than 0.05 were considered as statistically significant.

Results:

The average weight of the sample of Tenon′s tissue excised was 5.51 ± 4.42 mg (range: 0.9-17.1) and the average estimated MMC concentration found to be present in Tenon′s tissue using HPLC was 18.67 ± 32.36 × 10⁻⁶ moles/kg of the tissue (range: 0.38-197.05 x 10⁻⁶ ). In 36 of the 41 patients (87.80%), the MMC concentration reached above 2 x 10⁻⁶ moles/kg of the tissue concentration required to inhibit human conjunctival fibroblasts.

Conclusions:

Mitomycin C does permeate into the subconjunctival tissue after supraconjunctival application for 3 min. Application of MMC over the conjunctiva may be a useful alternative to subconjunctival or subscleral application during routine trabeculectomy and as an adjunct for failing blebs.

Hypotony maculopathy

Hypotony maculopathy, first described in 1954 by Dellaporta, usually occurs after antiglaucomatous surgery or after perforating eye injuries; it is characterized by hypotony associated with fundus abnormalities, including papilloedema, vascular tortuosity and chorioretinal folds. In hypotony maculopathy, the scleral wall collapses inward, resulting in redundancy of the choroid and retina, leading to chorioretinal wrinkling. As the antero-posterior diameter of the vitreous cavity decreases, the very thick perivofeal retina surrounding the very thin foveal retina is thrown into radial folds around the fovea. It has been reported that hypotony maculopathy occurs in up to 20% of cases of glaucoma filtering surgery and has become more common after the introduction of antimetabolites. Young age, myopia, primary filtering surgery, systemic illnesses and elevated preoperative intraocular pressure (IOP) have been found to be associated with hypotony maculopathy. Hypotony maculopathy is treated with procedures designed to elevate IOP, which may reverse the inward scleral bowing and improve visual acuity. The successful treatment of hypotony maculopathy depends on the correct identification of its cause. Once the cause is detected, treatment should be employed as soon as possible because delayed normalization of the IOP may result in permanent macular chorioretinal changes and poor vision. This review will explore the definition, mechanisms, clinical findings and treatment of hypotony maculopathy.

Uses and complications of mitomycin C in ophthalmology

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

Effects of daunorubicin, mitomycin C, azathioprine and cyclosporin A on human retinal pigmented epithelial, corneal endothelial and conjunctival cell lines

BACKGROUND

We wished to investigate the toxicity of four immunosuppressant and antimetabolic drugs, which are known to influence postoperative wound healing, on three different human ocular cell lines.

METHODS

Acute toxicity to cyclosporin A, azathioprine, mitomicyn C and daunorubicin was assessed in Chang cells by monitoring their uptake of propidium iodide during a 3-h period. Chronic toxicity was assessed by monitoring the proliferation and viability of subconfluent cultures of Chang cells, human corneal endothelial cells (HCECs) and retinal pigmented epithelial (RPE) cells after continuous exposure to the drugs for 7 days.

RESULTS

Acute toxicity testing revealed no obvious effects. However, the chronic toxicity tests disclosed a narrow concentration range over which cell proliferation decreased dramatically but calcein metabolism was sustained. Although the three lines reacted similarly to each agent, HCECs were the most vulnerable to daunorubicin and mitomycin. At a daunorubicin concentration of 0.05 microg/ml, a 75% decrease in calcein metabolism (P < 0.001) and a > or = 95% cell loss (P < 0.001) were observed. At a mitomycin concentration of 0.01 mug/ml, cell density decreased by 61% (P < 0.001) without a change in calcein metabolism, but at 0.1 microg/ml, the latter parameter decreased to 12% (P = 0.00014). At this concentration the proliferation of Chang and RPE cells decreased by more than 50%, whilst calcein metabolism was largely sustained. Cyclosporin inhibited cell proliferation moderately at lower concentrations (< 5 microg/ml; P=0.05) and substantially at higher ones, with a corresponding decline in calcein metabolism. Azathioprine induced a profound decrease in both parameters at concentrations above 5 microg/ml.

CONCLUSION

Daunorubicin, cyclosporin and azathioprine could be used to inhibit excessive intraocular scarring after glaucoma and vitreoretinal surgery without overly reducing cell viability. The attributes of immunosuppressants lie in their combined antiproliferative and immunomodulatory effects.