The vitreous body is a transparent gel occupying the posterior segment of the ocular globe. In diseased states, vision is obscured by haemorrhage or opacity or may be lost because of retinal detachment. The design of instruments for pars plana vitrectomy is based on the therapy of the disease. Conclusions drawn from human and mechanical factor analysis have been grouped into four categories: (a) instrument design parameters; (b) surgical procedure; (c) intraocular illumination; and (d) indications and results. Possible extensions with fibre optic illumination of the infusion system are indicated.