Intraoperative 5-fluorouracil application during primary trabeculectomy in Nigeria: a comparative study

Differences in the Surgical Outcomes of Glaucoma Surgery in Patients of African Caribbean Descent

PURPOSE

People of African Caribbean Descent (ACD) have a higher prevalence of glaucoma compared to people of European Descent (ED) and there is uncertainty if treatment outcomes are equivalent between the two groups. To assess surgical failure rates comparing ACD with ED focusing on trabeculectomy, aqueous shunt implantation, non-penetrating filtering surgery (NPFS), and minimally invasive glaucoma surgery (MIGS) by performing a systematic review in accordance with the PRISMA guidelines and to determine whether there is any evidence in to show a difference in success rates based on race.

METHODS

A systematic review of articles using the CENTRAL, Ovid MEDLINE, PubMed, EMBASE, and ClinicalTrials.gov databases was completed. Additional studies were identified by contacting clinical experts and searching bibliographies. All retrospective and prospective studies on trabeculectomy, aqueous shunt implantation, NPFS, and MIGS that included at least 20% ACD were included. Two review authors independently screened search results for eligibility and inclusion and extracted the data using pre-determined fields.

RESULTS

A total of 76 studies were identified for inclusion in the review. Glaucoma surgical outcomes in ACD appear to be poorer compared to ED overall, particularly for trabeculectomy. Data on NPFS are limited, but the studies completed thus far demonstrate surprisingly good results for ACD, particularly when compared to ED, who have significantly lower pre-operative IOPs. Evidence from studies investigating aqueous shunts does not suggest that ACD have poorer outcomes than ED. There is not enough data on MIGS to provide a significant conclusion.

CONCLUSION

In a population where trabeculectomy may no longer be the gold standard, sufficiently powered studies assessing surgical outcomes in aqueous shunts, NPFS, and MIGS are needed to guide clinicians.

What Glaucoma Surgical Rate could Serve as a Target for West Africa? A Systematic Review

Aim and objective

This study aimed to use the available evidence to model a glaucoma surgical rate (GSR), which could serve as a target for West Africa.

Materials and methods

A comprehensive literature search was performed in Medline, Embase, Global Health, and CINAHL, and studies published between January 1, 2000, and June 19, 2020, were retrieved. Study selection, quality appraisal, and data extraction were performed and the results of individual studies aggregated and presented using a narrative synthesis. Using these data, we aimed to construct a target GSR per million population per year that is sufficient to offer trabeculectomy to most patients with glaucoma who are diagnosed, and for whom other treatment options are either ineffective or inappropriate. The findings were then used to develop a trabeculectomy target for West Africa.

Results

Initial searches returned 633 references, of which 33 unique studies were eligible for inclusion. The glaucoma prevalence population-based surveys identified, reported a wide range of prevalence of primary open-angle glaucoma (POAG) ranging from 1.0 to 8.4%. The studies on glaucoma medications reported intraocular pressure (IOP)-lowering effects ranging from 12.8% (beta-blockers) to 63.7% (Timolol–Latanoprost combinations). The adherence rate to antiglaucoma medications spanned from 10.3 to 82.3%. Regarding selective laser trabeculoplasty (SLT), only two studies were found. All the studies on trabeculectomy showed a significant reduction in IOPs at different follow-up periods with many reporting the absence of vision-threatening complications. From these available data, a GSR of 50 trabeculectomies was suggested for countries in West Africa.

Conclusion

This trabeculectomy target metric is expected to minimize POAG blindness in the West African subregion.

Clinical significance

The proposed GSR will enable eye care workers involved in glaucoma care in West Africa to assess their efforts compared with the proposed target. The gap will signal the potential for improvement.

How to cite this article

Eni EN, Nolan W, Eval B, et al. What Glaucoma Surgical Rate could Serve as a Target for West Africa? A Systematic Review. J Curr Glaucoma Pract 2021;15(1):19–27.

All‑trans‑retinoic acid modulates TGF‑β‑induced apoptosis, proliferation, migration and extracellular matrix synthesis of conjunctival fibroblasts by inhibiting PI3K/AKT signaling

Conjunctival fiber generation is implicated in a wide spectrum of ocular diseases. Conjunctival wound healing is characterized by inflammation followed by re‑epithelialization, synthesis of new extracellular matrix (ECM), wound contraction and subconjunctival scar formation. The primary cause for the failure of glaucoma filtration surgery results from the excessive scarring of the filtering bleb. All‑trans‑retinoic acid (ATRA), a derivative of vitamin A, is a potent regulator of ECM synthesis, growth and differentiation. Following a previous study, which revealed that ATRA could inhibit transforming growth factor‑β‑induced human conjunctival fibroblast (HConF)‑mediated collagen gel contraction, the present study aimed to investigate the effects of ATRA on HConF migration, apoptosis, proliferation and ECM synthesis. To achieve this, the present study used Transwell migration, wound healing and Cell Counting Kit‑8 assays, flow cytometry and western blot analysis. In addition, the present study aimed to elucidate the mechanism of ATRA in mediating resistance to conjunctival scar formation. ATRA treatment resulted in an increased level of HConF apoptosis, reduced proliferation and migration, decreased collagen I and fibronectin expression, and decreased phosphorylation of PI3K and AKT. Thus, the present study showed a role for ATRA in inhibiting HConF migration, proliferation and ECM synthesis, and in promoting HConF apoptosis through the inhibition of the PI3K/AKT signaling pathway.

NPPB modulates apoptosis, proliferation, migration and extracellular matrix synthesis of conjunctival fibroblasts by inhibiting PI3K/AKT signaling

When treating glaucoma, excessive scar tissue reactions reduce the postoperative survival rate of the filtering bleb. Accumulating evidence has demonstrated that the proliferation, migration and extracellular matrix (ECM) synthesis of fibroblasts are important molecular mechanisms underlying scar formation. Recent evidence has demonstrated that chloride channels play an important role in controlling cell proliferation, apoptosis, migration and the cell cycle process in several cell types, but the effects of chloride channels on conjunctival fibroblasts have not be studied. The aim of the present study was to investigate the effects of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) on cell proliferation, apoptosis, migration, cell cycle progression and ECM synthesis in human conjunctival fibroblasts (HConFs), and to further investigate the mechanism of resistance to scar formation following glaucoma filtration surgery. HConFs were exposed to NPPB or lubiprostone. Cell proliferation and viability was evaluated using the Cell Counting Kit-8. Cell migration was measured using Transwell migration and scratch‑wound assays. Flow cytometry was used to study apoptosis and cell cycle progression. Quantitative polymerase chain reaction and western blot analyses were performed to determine mRNA and protein expression levels, respectively. Following NPPB treatment, HConFs exhibited reduced proliferation and migration, along with increased apoptosis. NPPB also inhibited cell cycle progression by arresting cells in the G0̸G1 phase and reducing collagen I and fibronectin expression, as well as the phosphorylation of phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT). However, lubiprostone treatment exerted the opposite effects on HConFs. Therefore, NPPB treatment inhibited proliferation, migration, cell cycle progression and synthesis of the ECM, while promoting apoptosis in HConFs, by inhibiting the PI3K̸AKT signaling pathway.

Modulation of Fibroblasts in Conjunctival Wound Healing

Modulating conjunctival wound healing has the potential to improve outcomes after glaucoma filtration surgery and for several ocular disorders, including ocular cicatrial pemphigoid, vernal keratoconjunctivitis, and pterygium. Although anti-inflammatories and antimetabolites have been used with success, these nonspecific agents are not without their complications. The search for novel and more targeted means to control conjunctival fibrosis without such limitations has brought much attention to the regulation of fibroblast proliferation, differentiation, extracellular matrix production, and apoptosis. This review provides an update on where we stand with current antifibrotic agents and outlines the strategies that novel agents use, as they evolve from the bench to the bedside.

Glaucoma Surgery Outcome in Rwanda

PURPOSE

To assess long-term intraocular pressure (IOP) outcome after adult trabeculectomy surgery in Central Africa.

PATIENTS AND METHODS

All adult glaucoma patients who underwent trabeculectomy surgery in the Kabgayi Eye Unit, Rwanda between August 2003 and March 2008 were invited for a follow-up visit. Surgical and clinical data were collected from medical records. At the study visit, best-corrected visual acuity was measured and Goldmann applanation tonometry and biomicroscopy were done. Good IOP outcome was defined as both an IOP<21 mm Hg and achieving ≥30% reduction from the preoperative IOP. Considering first operated eyes, univariate and multivariate logistic regression was used to investigate risk factors for failure.

RESULTS

Of 163 individuals operated 3 had died, 118 (74%) participated. Preoperatively, the mean IOP was 31 mm Hg (SD=11; range, 12 to 60). At the time of the follow-up study visit the mean postoperative IOP was 13 mm Hg (SD=5; range, 4 to 35). Good IOP outcome was achieved in 132 eyes (84%). Univariate analysis suggested a protective effect against failure of use of antimetabolites [odds ratio (OR)=0.39; 95% confidence interval (CI), 0.14-1.11; P=0.07] and a decrease in success with length of follow-up (OR=3.57; 95% CI, 1.09-12.50; P=0.03). The latter remained borderline significant with multivariate analysis. Seven eyes went from previously better vision (at least hand movements) down to perception of light or no perception of light after trabeculectomy. Particularly a flat anterior chamber in the first postoperative week (OR=0.07; 95% CI, 0.01-0.49; P<0.001) and late hypotony (OR=0.04; 95% CI, 0.002-0.99; P=0.004) were significant risk factors for severe visual loss.

CONCLUSIONS

Trabeculectomy with antimetabolites is one of the best available options for glaucoma management in Africa. However, the IOP control reduced at a follow-up duration beyond 2 years, highlighting the importance of regular long-term follow-up.

Is Beta Radiation Better than 5 Flurouracil as an Adjunct for Trabeculectomy Surgery When Combined with Cataract Surgery? A Randomised Controlled Trial

INTRODUCTION

In an African setting surgery is generally accepted as the treatment of first choice for glaucoma. A problem with trabeculectomy surgery for the glaucomas is the frequent co-existence and exacerbation of cataract. We report a randomized controlled trial to compare the use of beta radiation with 5FU in combined cataract and glaucoma surgery.

PARTICIPANTS AND METHODS

Consenting adults aged >40 years with glaucoma, an IOP>21mmHG and cataract were enrolled and randomised to receive either 1000cG β radiation application or sub-conjunctival 5fluorouracil (5FU) at the time of combined trabeculectomy and phaco-emulsification with lens implant surgery.

RESULTS

385 individuals were eligible for inclusion of whom 301 consented to inclusion in the study (one eye per patient). 150 were randomised to the 5FU arm and 151 received β radiation. In the 12 months following surgery there were 40 failures (IOP>21mmHg) in the 5FU arm and 34 failures in the beta arm. The hazard ratio for the beta radiation arm compared to the 5FU arm, adjusted for IOP at baseline, was 0.83 (95% c.i. 0.54 to 1.28; P = 0.40). The improvement from mean presenting visual acuities of 0.91 and 0.86 logMAR to 0.62 and 0.54 in the 5FU and beta arms respectively was comparable between groups (P = 0.4 adjusting for baseline VA). Incidence of complications did not differ between the two groups.

DISCUSSION

This study highlights several important issues in the quest for a therapeutic strategy for the glaucomas in an African context. Firstly, there is no evidence of an important difference between the use of 5FU and beta radiation as an anti-metabolite in phacotrabeculectomy. Secondly phacotrabeculectomy is a successful operation that improves visual acuity as well as controlling IOP in a majority of patients. Although the success of trabeculectomy in lowering IOP is reduced when combined with phacoemulsification compared with trabeculectomy alone, this finding has to be set against the possible need for subsequent cataract surgery following trabeculectomy alone, which represents a second trip and expense for the patient and results in 10-61% failure of the trabeculectomy at one year post-cataract surgery.

TRIAL REGISTRATION

ISRCTN Registry ISRCTN36436933.

Wound modulation after filtration surgery

Filtration surgery is the standard invasive procedure for the management of intraocular pressure in advanced glaucoma. The key to a successful outcome is to modulate the normal wound healing cascade that leads to closure of the newly created aqueous outflow pathway. Antifibrotic agents such as mitomycin C and 5-fluorouracil have been increasingly used to modulate the wound healing process and increase surgical success. Although these agents have proven efficacy, they also increase the risk of complications. Efforts have centered on the identification of novel agents and techniques that can influence wound modulation without these complications. We detail new agents and methods under investigation to control wound healing after filtration surgery.

A review of trabeculectomies at a nigerian teaching hospital

SUMMARY BACKGROUND

Trabeculectomy is the commonest surgical procedure for glaucoma. The outcome of trabeculectomy in the treatment of all types of glaucoma over a 4-year period in a Nigerian population was reviewed.

OBJECTIVE

To determine the surgical rate and effectiveness of trabeculectomy in lowering of intra ocular pressure (IOP) and preservation of visual acuity.

METHODS

Retrospective review of all trabeculectomies (TEs) done at the Obafemi Awolowo University Teaching Hospital, Ile-Ife between January 1999 and December 2002. The outcome of trabeculectomy was correlated with the biomicroscopic appearance of the filtering bleb, visual acuity and IOP levels. Descriptive statistics were applied to the data.

RESULTS

Of the 647 glaucoma patients only fifty-three (8.2%), 34 males and 19 females, had trabeculectomy done during the study period. Seventy-two consecutive eyes of these 53 Nigerian patients were operated upon. Majority, 63 (87.5%) were in the primary glaucoma group of which 46 (63.9%) were open angle glaucoma type. Nine eyes (12.5%) belonged to the secondary glaucoma group (neovascular, uveitic and traumatic angle recession). Successful control of intra-ocular pressure with medical therapy was recorded only in 13.9% of the patients. The mean pre-operative and first post-operative day IOP were 32.5+/- 6.2mmHg and 10.6+/- 2.3mmHg respectively. Mean post-op IOP at 3 months and one year were 14.6+/- 4.2mmHg, and 13.5+/- 5.8mmHg respectively. One year after surgery 34 eyes (61.8%) had intraocular pressure (IOP) of 20mm Hg or less without glaucoma medication. Hyphema 11 (15.3%) was the commonest post-operative complication documented.

CONCLUSIONS

Surgical intervention in the management of glaucoma, especially trabeculectomy is not commonly done in this Teaching Hospital. IOP control with medication alone is not adequate in the long term. A significant proportion of the eyes (61.8%) had complete success in IOP control following trabeculectomy.

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.

Intra-operative 5-FU in Glaucoma Surgery: A Nigerian Teaching Hospital Experience

Background:

5-Fluorouracil (5-FU) is an anti-metabolite used as an adjunct during the initial stages of a trabeculectomy to prevent excessive post-operative scarring and thus reduce the risk of failure.

Objectives:

To assess the effects of intra-operative 5-FU in trabeculectomy in Nigerians.

Methods:

Trabeculectomy with an intra-operative sponge soaked with 5-FU was performed in 49 eyes of 34 patients. The reduction in intra-ocular pressure (IOP), Visual acuity changes and complications were noted.

Results:

The mean presenting and preoperative IOP was 35.6+/-12.5mmHg and 25.5+/-6.6mmHg respectively. The mean post-operative IOP was 10.0+/- 5.2mmHg on the second post-operative day and 16.5+/7.3mmHg at 3 months. Post-operative complications included ocular hypotony in 4 (25 percent), shallowing of anterior chamber in 3 (18.8 percent), hyphema and cystic bleb in 2 (12.5 percent) each. None had bleb failure. 5 FU appears to reduce the relative risk of failure of trabeculectomy in those undergoing surgery for the first time (relative risk 0.29, 95 percent confidence interval 0.16 to 0.53).

Conclusions:

The use of 5-FU during trabeculectomy is associated with significant benefit in terms of intraocular pressure lowering beyond 3 months postoperatively. The results of surgery in Nigerian patients compare well with other reported series.

Post-operative complication of trabeculectomy in Ibadan, Nigeria: outcome of 1-year follow-up

OBJECTIVE

To describe the post-operative complications reported in patients who had trabeculectomy with and without antimetabolite in UCH, Ibadan between 1999 and 2003 and the success rate achieved in term of the post-operative intraocular pressure (IOP).

METHODS

A retrospective study of the records of glaucoma patients who had trabeculectomy between 1999 and 2003 and had follow-up in UCH Ibadan eye clinic for a minimum of 1 year was carried out.

RESULTS

Seventy-six out of 171 eyes that had trabeculectomy during the period were reviewed. Mean age of patients was 49.4 years. The mean preoperative IOP was 31.8 mm Hg. Success rate of 79.4% was achieved in term of IOP control at a year of follow-up. The most frequent early post-operative complication was shallow AC (13 eyes; 17.1%) while late complication was elevated IOP (21 eyes; 27.6%). Others were encapsulated bleb 7.9% and hyphema 3.9%. There was no significant difference in the complication rate in those who had intraoperative antimetabolite (5-fluorouracil) when compared with those operated without antimetabolite.

CONCLUSION

Guarded filtration surgery is effective in controlling IOP. Most of the complications noted were transient and not visually threatening.

The Clinical Applications of Fluorouracil in Ophthalmic Practice

Fluorouracil (5-fluorouracil, 5-FU) is a pyrimidine analogue that was originally known for its widespread use as an anticancer drug. The ability of 5-FU to reduce fibroblastic proliferation and subsequent scarring has made it an important adjunct in ocular and periorbital surgeries. It is used in primary glaucoma filtering surgeries and in reviving failing filtering blebs, in dacryocystorhinostomy, pterygium surgery, and in vitreoretinal surgery to prevent proliferative vitreoretinopathy. In addition, 5-FU is also gaining recognition in the treatment and surgical management of ocular surface malignancies like ocular surface squamous neoplasia; however, the specific action of the drug on highly proliferating cells limits its use in primary acquired melanosis of the conjunctiva. When applied topically, this drug has a low rate of sight-threatening adverse effects, is inexpensive, and is easy to administer, making it an important tool in enhancing the success rate in ophthalmic surgery and in reducing the recurrence of ocular surface neoplasia.

Deep sclerectomy and low dose mitomycin C: a randomised prospective trial in west Africa

AIM

To study the efficacy and safety of deep sclerectomy (DS) augmented with intraoperative low dose mitomycin C (MMC) in a west African population.

METHODS

Prospective, randomised, controlled trial. Trial participants were Nigerian patients with medically uncontrolled primary open angle glaucoma undergoing primary surgery at Maja Hospital, Lagos, Nigeria. 39 eyes of 39 patients undergoing DS were randomised into receiving intraoperative MMC 0.25 mg/ml for 2 minutes at the end of procedure (DS-MMC) and a control group (DS-noMMC).

RESULTS

There were 21 patients in the DS-noMMC and 18 in the DS-MMC group with no difference in the preoperative characteristics of the groups. Mean follow up was 16.4 (SD 11.3) months. The probability of maintaining an intraocular pressure less than 18 mm Hg with or without additional medications (95% confidence intervals) at 1 year was 70% (47-92%, 95%) and 79% (57-100%), and at 18 months was 35% (8-62%) and 38% (7-69%) for the DS-noMMC and DS-MMC groups, respectively, with no difference in success rates (p = 0.6). An IOP of less than 18 mm Hg without additional medication was maintained in 65% (41-89%) and 73% (49-96%) at 1 year and 24% (8-48%) and 13% (13-46%) at 18 months for the DS-noMMC and DS-MMC groups, respectively (p = 0.5). There were no serious complications related to the procedure.

CONCLUSIONS

The success rates of DS in black west African glaucoma patients, as performed in this study, were low. The study did not achieve sufficient power to detect whether low dose intraoperative MMC application can increase success rates of DS.