In the treatment of glaucoma, trabeculectomy surgery provides a drainage system for the eye and allows for the lowering of the pressure inside the eye. The flow through the surgically created fistula determines the intraocular pressure. Titrating suture tightness is important to achieving the desired post-operative intraocular pressure. This process is not straightforward and intraocular pressures are often too high or too low post-operatively.