Interventions for trachoma trichiasis

Methodological quality of the review: High confidence

Author: Burton M, Habtamu E, Ho D, Gower EW

Geographical coverage: Not specifed

Sector: Trachoma

Sub-sector: Trachoma intervension

Equity focus: None specified

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background:

Trachoma is the world’s leading cause of infectious blindness. The World Health Organisation (WHO) has endorsed the SAFE strategy in order to eliminate blindness due to trachoma by 2020 through “surgery, antibiotics, facial cleanliness and environmental improvement.’’  It is important to review evidence for the effectiveness of the SAFE strategy.

Objectives:

To assess the effects of interventions for trachomatous trichiasis for people living in endemic settings.

Main findings:

In total, 13 studies including 8586 participants were included in the review. Most of the studies were conducted in sub-Saharan Africa. The majority of the studies were of a low or unclear risk of bias. Five studies compared different surgical interventions. Most surgical interventions were performed by non-physician technicians.

The studies suggest the most effective surgery is full-thickness incision of the tarsal plate and rotation of the terminal tarsal strip. Pooled data from two studies suggested that the bilamellar rotation was more effective than unilamellar rotation (odds ratio [OR] 0.29, 95% CI 0.16 to 0.50). Use of a lid clamp reduced lid contour abnormalities (OR 0.65, 95% CI 0.44 to 0.98) and granuloma formation (OR 0.67, 95% CI 0.46 to 0.97). Absorbable sutures gave comparable outcomes to silk sutures (OR 0.90, 95% CI 0.68 to 1.20) and were associated with less frequent granuloma formation (OR 0.63, 95% CI 0.40 to 0.99). Epilation was less effective at preventing eyelashes from touching the globe than surgery for mild trichiasis, but had comparable results for vision and corneal change.

Peri-operative azithromycin reduced post-operative trichiasis; however, the estimate of effect was imprecise and compatible with no effect or increased trichiasis (OR 0.85, 95% CI 0.63 to 1.14; 1954 eyes; 3 studies).

Community-based surgery when compared to health centres increased uptake with comparable outcomes. Surgery performed by ophthalmologists and integrated eye care workers was comparable. Adverse events were typically infrequent or mild and included rare postoperative infections, eyelid contour abnormalities and conjunctival granulomas.

Overall, surgical intervention was found to be the best technique and is preferably delivered in the community. Post-operative azithromycin was found to improve outcomes where overall recurrence was low.

Implications for further research: further research is needed to improve understanding of the reasons why trichiasis recurs and to investigate targets for possible adjuvant therapy. Further trials are also needed to compare the long-term results of bilamellar and posterior lamellar tarsal rotation surgery. Entropion severity must be taken into account in the design of future trials.

Methodology:

Authors conducted a search on CENTRAL, MEDLINE, EMBASE, the ISRCTN registry, clinicaltrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) with no restrictions on language or year of publication. In addition, authors contacted experts and researchers in the field to ask them for details of published, unpublished or ongoing trials and searched the reference lists of relevant trials.

Studies were included if they were randomised controlled trials of any intervention for trachomatous trichiasis. Participants in the trials were people with trachomatous trichiasis, defined as one or more eye lashes touching the globe when looking straight ahead. The primary outcome measure for this review was post-operative trichiasis. Two authors independently assessed the full text of studies for inclusion in the review, and one author independently entered the data in to RevMan 5, which was checked by another author.

For data analysis, considerable heterogeneity among the results limited the possibility of meta-analyses for all interventions identified. Authors conducted a meta-analysis for peri-operative azythromyacin and bilamellar tarsal rotation, and presented odds-ratios for other interventions. Interventions included: surgical technique, epilation, lid taping, antibiotic treatment, alternative suture materials, surgery setting and personnel performing surgery.

Applicability/external validity:

The authors mentioned that failure to attend for an operation is a major obstacle to successful trichiasis surgery. Further research is required to identify other means of increasing the proportion of people who attend for surgery. It may be possible to identify the perceived benefits of lid surgery to the patient – such as free transport or improved cosmesis – and to use these perceived benefits to persuade others to attend.

Geographic focus:

Included studies were from Asia and sub-Saharan Africa and findings may only be relevant to similar settings.

Summary of quality assessment

Overall, there was high confidence in the conclusions about the effects of this study as minor limitations were identified. This review was based on comprehensive searches of the literature, although the list of excluded studies was not provided but this may be due to it was not practical to add such a long list. Methods used to screen studies for inclusion and extract data were appropriately conducted minimising bias.