To measure vitreous collagen fragments length after pars plana vitrectomy performed at different cut rates

Pars plana vitrectomy consists in the removal of vitreous obtained with a vitreous cutter. The instruments attracts vitreous in its port through active suction and cuts with a blade at different cut rates. There is no consensus as to which cut rate would be ideal in order to minimize traction, neither there is agreement on whether increasing cut rates generate shorter collagen fragments or the fluid turbulence creates unpredictable flows at the port generating fragments of different length.

The investigators plan to gather vitreous cut at 1,000, 2,000, 4,000, 8,000 and 16,000 cuts per minute and measure vitreous collagen average length

Inclusion Criteria:

• patient undergoing pars plana vitrectomy for:
• macular pucker
• macular hole-
• retinal detachment
• age >18

Exclusion Criteria:

• unwilling to participate
• previous trauma
• vitreous haemorrhage

patients over 18 undergoing pars plana vitrectomy for macular surgery or retinal detachment