Gower 2013.

Methods	Study Design: parallel group randomised controlled trial bilamellar tarsal rotation surgery with or without a TT clamp Eyes: both eyes of bilateral cases were included in the analysis. Appropriate adjustment was made in the analysis for bilateral cases.
Participants	Country: Tanzania Setting: health centres Number of participants: 1917 Number of Eyes: 3345 Lost to follow up: 51 Male: 490, Female: 1427
Interventions	(1) Standard bilamellar tarsal rotation (2) Bilamellar tarsal rotation performed with a TT clamp
Outcomes	Primary Outcome: was defined as one or more of the following: recurrent trichiasis, eyelid contour abnormality or granuloma. Secondary outcomes: post‐operative trichiasis, eyelid contour abnormality or granuloma individually. Follow‐up: 6 weeks, 12 months, 24 months.
Notes	18 different surgical technicians performed the surgery. Surgeons were randomly allocated at the outset to only perform one of the two types of operation. Each recruitment day there were 4 surgical technicians operating – 2 standard procedure and 2 with the TT clamp. Patients with TT were randomly allocated to one of the 4 surgical technicians operating. Funder: Bill and Melinda Gates Foundation
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote "Randomization assignments were created using permuted block sizes of 6 to 12".
Allocation concealment (selection bias)	Low risk	Quote "Randomization assignments were placed in opaque envelopes and stored in a locked office until distribution".
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants and surgical technicians were not masked to the allocation; however, this is unlikely to have affected the outcome measure.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote "Examinations were conducted by a single trained examiner who was not involved in enrolment, randomization, or surgical procedures".
Incomplete outcome data (attrition bias) All outcomes	Low risk	98% follow‐up rate.
Selective reporting (reporting bias)	Low risk	No study protocol available. Clear analytical approach in methods.