Recurrent trichiasis after surgery is a major problem in the prevention of blindness from trachoma. Although in tightly supervised clinical trials recurrence rates as low as 7% at 1 year have been reported, it is likely that rates are much higher under operational conditions.
13,18 In our study, the recurrence rate at 4 years was 41%. Most recurrences occurred within the first year (32% at 6 months, 40% at 12 months).
10 However, an additional 26 cases of recurrence were recorded between 1 and 4 years after surgery. The uncensored recurrence rate at 4 years (including those who had died or were lost to follow-up) is likely to have been higher than 41%, as the recurrence rate at 12 months in these individuals was 48%, compared with 37% in those who were also seen at 4 years. Despite these high recurrence rates, the lash burden in those eyes with trichiasis was much less than at baseline. The risk of CO increases with increasing lash burden.
10,17 Therefore, even partially successful surgery is likely to be beneficial.
Early recurrence is probably related to surgical factors, whereas late recurrence may reflect an ongoing cicatrizing process. In our study, 75% of recurrent TT had developed by 6 months, and there was significant intersurgeon variation.
10 Therefore, in this low-prevalence setting, there were probably important issues relating to surgical technique and quality that should be addressed. No long-term prospective studies of postsurgical recurrence have been reported from high-prevalence settings, where late recurrence driven by ongoing
C. trachomatis infection may be more frequent.
BLTR and PLTR are the most commonly used procedures to treat TT in trachoma-endemic settings. PLTR is used in The Gambia. The WHO recommends BLTR, although the only small comparative trial of the two procedures found similar outcomes.
22,23 A larger trial with longer follow-up is needed, to conclusively determine whether these two procedures are comparable. Variations in surgical technique are likely to influence the success of the operation: incision length, degree of eversion, suture material, and tension.
18,24 As with other surgical procedures, it is likely that performing the surgery more frequently leads to improved quality and may in part explain the significant intersurgeon variation in outcomes reported at 1 year, although all surgeons receive the same National Eye Care Programme training.
10 In light of that study, all Gambian trichiasis surgeons underwent refresher training and recertification. High early recurrence rates may result from the lid's reverting to the entropic position soon after the removal of the silk sutures, removed at 7 to 10 days per WHO guidelines.
22 Stable wound healing in heavily scarred tissue may not have occurred by this time. A recent report suggested that better results are attained with the use of absorbable sutures, perhaps because they hold the lid in position for a longer period. However, differences in socioeconomic status between groups receiving different suture materials may have confounded this finding.
14
The association between severe disease and recurrence has been reported.
10,17,18,25–30 The patients in our study tended to have slightly more severe trichiasis than those in other trials, and that difference may have contributed to the less favorable outcome. More severe disease makes the surgery harder, especially when the lids are shortened, more scarred, and inflamed. Similarly, repeat surgery is technically more challenging, as lids are often more scarred and distorted by previous surgery. These cases should be referred to an ophthalmologist or experienced TT surgeon.
Patients with trichiasis often had persistent tarsal conjunctival inflammation that was strongly associated with the presence of recurrence, particularly major recurrence at 4 years. However, the causality in the relationship between inflammation and recurrence is unclear and may go both ways. We suggest that, although early recurrence primarily results from surgical factors, a chronic inflammatory and cicatrizing process causes the development of recurrence many years later.
C. trachomatis infection is probably the major driver of active disease in children and perhaps postsurgical recurrence in high-prevalence areas, although this has never been demonstrated. However, chlamydial infection was rare and not associated with recurrence in these Gambian patients, and its role remains uncertain in other populations.
10,19,26 Pathogenic bacteria were strongly associated with recurrence at 1 year in this cohort of patients, suggesting that they may play a role in driving the clinically observed inflammation.
10 In addition, a large prospective sample with repeat bacteriology investigations, and laboratory studies of the inflammatory mediators would be needed to further investigate this process. Other factors, for which there is good evidence of an association with increased recurrence, are a history of previous surgery, older age, female sex, and immunogenetic factors.
1,10,17–19,28,31–33 Recurrent trichiasis has been associated with the use of three or more sutures in surgery, making postoperative adjustments to the sutures, living with children who are infected with
C. trachomatis, and eye laterality.
1,14,19,24,28
This group of patients had high levels of visually disabling CO (36%). Many patients had bilateral opacification (21%) and, given the worsening corneal disease and trichiasis recurrence observed over 4 years, many of these individuals are at high risk of blindness. Major TT at baseline is a strong risk factor for CO at 4 years. A greater lash burden probably has a greater abrasive effect. However, the large, dense, deep scars that are seen in patients with TT suggest that secondary microbial keratitis plays a role. This notion is supported by the strong association between the presence of a conjunctival bacterial pathogen at baseline and CO at 4 years. It is likely that eyes with more trichiatic lashes are more susceptible to damaging bacterial infections. Prevention and/or prompt treatment of pathogenic conjunctival and corneal bacterial infection in patients with TT is likely to be beneficial, although studies to assess this possibility have not been conducted. Despite the likely progression of cataract and CO in some patients (22%), the visual acuity was significantly better in 99 patients at 1 year and in 47 patients at 4 years when compared with baseline. There was a nonsignificant trend toward improving vision in patients without recurrence at 4 years. Successful trichiasis treatment probably facilitates visual improvement by allowing a normal tear film, which reduces photophobia and possibly enables corneal scars to fade slightly. It is important to treat patients with TT as soon as possible, and it seems likely that well-conducted epilation is a sensible interim measure for reducing lash burden until surgery takes place.
High recurrence rates in TT surgery are a major concern. Patients thought to be successfully treated remain at risk of recurrence. Individuals are likely to share any negative experience with other sufferers, discouraging the uptake of surgery. Both these factors greatly impede the control of blinding trachoma. The findings in this long-term, prospective study suggests that, in this environment, most recurrence occurs within the first few months after surgery and that surgical factors, such as technique and training, are very important determinants of the outcome. We have observed a strong association between increasing conjunctival inflammation and recurrent trichiasis at 4 years, which warrants further investigation.
Supported principally by Grant 01-030 from the International Trachoma Initiative with the addition of Grant 059134 from the Wellcome Trust/Burroughs Wellcome Fund. MJB is supported by Grant 080741/Z/06/Z from the Wellcome Trust and SNR by the Band Aid Foundation/Fight for Sight. The funders had no part in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the paper for publication.