The effect of infusion pressure on the outcomes of phacoemulsification surgery.

The Centurion phacoemulsification system with active sentry allows efficient cataract surgery with safe use of high vacuums, whilst allowing low and physiological infusion pressures, significantly lower than other surgical systems. There are reasons to expect that this will lead to patient benefit but it is uncertain if low infusion pressure during phacoemulsification will lead to improved outcomes. This is of particular interest in patients with vascular retinopathies such as diabetic retinopathy where the retinal vasculature is compromised, as well as glaucoma and other optic neuropathies where there is established nerve fibre layer loss.

The investigator will carry out a feasibility study with a two surgeon RCT of 70 patients with diabetic retinopathy and/or glaucoma undergoing phacoemulsification with randomisation of two different infusion pressures (low (30mmHg) versus the higher pressure (~70mmHg) as currently used) using the active sentry system with assessment of a range of exploratory endpoints.

Inclusion Criteria:

• Patients with cataract undergoing routine phacoemulsification with either diabetic retinopathy or glaucoma of any degree

Exclusion Criteria:

• Dense cataract precluding adequate retinal imaging
• posterior polar cataract
• subluxated cataract,
• other vision affecting pathology,
• severe glaucoma

All outcome assessors will be masked to treatment group allocation. The surgeon will not be masked.