Review question
This review addressed the question: "Which interventions improve the results of the treatment for trichiasis (in-turned eyelashes) caused by trachoma?"
Background
Trachoma is the commonest infectious cause of blindness in the world. It is caused by a bacterium called Chlamydia trachomatis. This infection causes inflammation and scarring of the surface of the eye, which results in the eyelid turning in (entropion) so that the eyelashes touch the eyeball. This is known as trachomatous trichiasis. The lashes can scratch the corneal surface, leading directly or indirectly (from secondary infections) to corneal opacity. Surgery to correct the eyelid deformity is the main treatment for the late stages of the disease. Most cases of trachomatous trichiasis occur in sub-Saharan Africa. They are generally treated by nurses with limited surgical training. Unfortunately the results of the surgery can be quite variable, with frequent post-operative trichiasis reported. Therefore, we wanted to find out what types of surgery and other interventions give the best results in treating this condition.
Study characteristics
We identified 13 randomised controlled trials. They were all conducted in trachoma-endemic countries (mostly in sub-Saharan Africa) with surgical interventions carried out by non-physician surgeons. Five studies compared different surgical treatments. Three studies investigated whether azithromycin antibiotic treatment after surgery improves the results. One study compared different types of sutures. One study compared surgery to the pulling out of eyelashes (epilation). One study compared the outcomes of treatments provided in the community with hospital care. One study compared the results of surgery performed by eye doctors with those of non-specialist technicians. The evidence is current to May 2015. Most studies were funded by government research councils or charitable foundations.
Key results
These trials suggested that the most effective surgery requires full-thickness incision of the tarsal plate and rotation of the edge of the eyelid. The use of a surgical lid clamp improves eyelid contour outcomes and reduces granuloma formation. Silk and absorbable sutures give comparable results. The addition of azithromycin treatment at the time of surgery may reduce post-operative trichiasis under certain conditions. Epilation is less effective than surgery at treating trichiasis, but has comparable results for vision and corneal change two years after intervention. Community-based surgery was more convenient for patients by reducing the time and expense of travelling to a conventional hospital, and it did not increase the risk of complications or recurrence. Surgery performed by ophthalmologists and by integrated eye care workers were both similarly effective. Destroying the lash roots by freezing or electrical ablation appeared to have low success rates and the equipment required is costly and can be difficult to maintain.
Quality of the evidence
The quality of the evidence from these randomised controlled trials was variable. Most were of a high quality. However, several were relatively small in size and several had potential bias problems due to the method of randomisation and masking.
No trials were designed to evaluate whether the interventions for trichiasis prevent blindness as an outcome; however, several found modest improvement in vision following intervention. Certain interventions have been shown to be more effective at eliminating trichiasis. Full-thickness incision of the tarsal plate and rotation of the lash-bearing lid margin was found to be the best technique and is preferably delivered in the community. Surgery may be carried out by an ophthalmologist or a trained ophthalmic assistant. Surgery performed with silk or absorbable sutures gave comparable results. Post-operative azithromycin was found to improve outcomes where overall recurrence was low.
Trachoma is the leading infectious cause of blindness. The World Health Organization (WHO) recommends eliminating trachomatous blindness through the SAFE strategy: Surgery for trichiasis, Antibiotic treatment, Facial cleanliness and Environmental hygiene. This is an update of a Cochrane review first published in 2003, and previously updated in 2006.
To assess the effects of interventions for trachomatous trichiasis for people living in endemic settings.
We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2015, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2015), EMBASE (January 1980 to May 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 7 May 2015. We searched the reference lists of included studies to identify further potentially relevant studies. We also contacted authors for details of other relevant studies.
We included randomised trials of any intervention intended to treat trachomatous trichiasis.
Three review authors independently selected and assessed the trials, including the risk of bias. We contacted trial authors for missing data when necessary. Our primary outcome was post-operative trichiasis which was defined as any lash touching the globe at three months, one year or two years after surgery.
Thirteen studies met the inclusion criteria with 8586 participants. 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. These trials 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 (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.