Lower infusion pressure during phaco was linked to better retinal perfusion in diabetic eyes

Design

Randomised clinical trial

Population

80 eyes with non-proliferative diabetic retinopathy having phaco, India

Primary outcome

Change in central retinal vessel density on OCT angiography

Effect

Greater increase with 20 mmHg vs 55 mmHg preset IOP at 1 week and 1 month

This randomised trial at an Indian cataract research centre allocated 80 eyes 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 increased after surgery, significantly more in the low-pressure group at one week and one month. Optic disc flux improved in both groups, more with low pressure at every visit. Peripapillary capillary density and postoperative pressure did not differ.

These are imaging surrogate outcomes, and the trial does not show any effect on vision or retinopathy progression. But lower infusion pressure is easy to set on modern machines, and the finding suggests it is worth considering in eyes whose circulation is already compromised.

• Consider a lower preset infusion pressure during phaco in eyes with diabetic retinopathy.
• Balance lower pressure against chamber stability; adjust if the chamber becomes unstable.
• Examine the retina after cataract surgery in diabetic patients, whatever the settings used.

Why it matters

Intraoperative pressure is a setting surgeons control, and diabetic eyes may tolerate high pressure less well.

Don't overread it

Vessel density on OCT angiography is a surrogate; the trial did not show any effect on vision or retinopathy.

The statistics, in plain English

With 40 eyes per group, the study can detect differences in imaging measures but not in clinical outcomes such as macular oedema or progression.

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