Effect of micropulse trans-scleral cyclophotocoagulation (MP-TSCPC) on aqueous humour dynamics in patients with glaucoma and ocular hypertension: an observational study.

Background

Glaucoma, a leading cause of irreversible blindness worldwide, affects over 60 million people globally and 700 000 in the UK. Elevated intraocular pressure (IOP) is the only modifiable risk factor for disease progression. Micropulse trans-scleral cyclophotocoagulation (MP-TSCPC) offers a promising alternative to conventional treatments by reducing IOP with minimal complications. Although MP-TSCPC is hypothesised to lower IOP by decreasing aqueous humour production and altering aqueous outflow, the precise mechanisms remain poorly understood.

Aims

This study aimed to evaluate the effects of MP-TSCPC on aqueous humour dynamics in patients with open-angle glaucoma and ocular hypertension (OHT), focusing on IOP, aqueous humour production and outflow pathways 6 months post treatment.

Results

Of the 31 patients undergoing MP-TSCPC, 61% were men, of which 71% were of black ethnicity, with 28 patients completing the 6-month follow-up. A significant 10% reduction in mean IOP (25.08±5.06 mm Hg to 22.56±4.89 mm Hg, p=0.005) and a 26.08% reduction in aqueous humour production (from 2.34±0.64 to 1.74±0.4 µL/min, p=0.0001) were observed. There were no statistically significant changes in tonographic outflow facility or uveoscleral outflow. Treatment was well-tolerated, with few mild adverse events reported.

Conclusion

This study demonstrates that MP-TSCPC reduces IOP primarily through decreased aqueous humour production, with no discernible impact on outflow pathways. These findings refine the understanding of MP-TSCPC's mechanism of action, highlighting its potential as a safe and effective treatment for glaucoma and OHT. Future studies should explore ways to enhance efficacy and long-term outcomes.