Lower pressure during phaco improved retinal perfusion in eyes with diabetic retinopathy

Design

Single-centre randomised clinical trial

Population

80 patients with non-proliferative diabetic retinopathy having phacoemulsification in India

Primary outcome

Percentage change in central retinal vessel density on OCTA

Effect

Greater increase with 20 vs 55 mmHg at 1 week and 1 month; better optic nerve flux at every visit

A randomised trial at a cataract research centre in Ahmedabad (Journal of Cataract & Refractive Surgery, 1 October 2026) assigned 80 patients with non-proliferative diabetic retinopathy having phacoemulsification to a preset intraocular pressure of 20 or 55 mmHg during surgery, and measured perfusion with OCT angiography up to one month.

Central retinal vessel density rose more in the low-pressure group, significantly at one week and one month. Optic nerve head flux improved more in the low-pressure group at every visit. Peripapillary capillary density and postoperative pressure did not differ.

These are imaging end points in a small trial, and visual outcomes and macular oedema rates were not the primary measure. But the change costs nothing on modern machines with active fluidics, and diabetic eyes are already vascularly compromised. It is Indian data on a very common Indian operation.

• Consider setting a lower intraoperative pressure for phaco in eyes with diabetic retinopathy where your machine allows.
• Check chamber stability at lower settings, especially in eyes with weak zonules.
• Continue standard measures to prevent postoperative macular oedema in diabetic eyes.
• Treat this as perfusion evidence, not proof of better vision.

Why it matters

A machine setting most surgeons never change may affect perfusion in already ischaemic retinas.

Don't overread it

The outcomes were OCT angiography measures, not vision or macular oedema.

The statistics, in plain English

With 40 eyes a group, the trial could detect clear differences in vessel density but not in rarer clinical events. A rise in a perfusion measure is a surrogate; it may or may not translate into better vision.

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