Cyclodiode vs micropulse transscleral laser treatment.

BACKGROUND

Continuous-wave transscleral cyclophotocoagulation (CW-TSCP) is usually reserved for advanced/refractory glaucoma. Micropulse transscleral laser therapy (MPTLT) utilises short energy pulses separated by 'off'-periods. MPTLT is postulated to have fewer complications, but its relative efficacy is not known. The National Institute for Health and Care Excellence (NICE) has deemed the evidence supporting MPTLT use of inadequate quality, limiting its use to research. This study aims to evaluate MPTLT efficacy and safety compared to CW-TSCP.

METHODS

This 24-month follow-up retrospective audit included 85 CW-TSCP and 173 MPTLT eyes at a London tertiary referral centre. Primary outcome was success rate at the last follow-up; defined as at least 20% intraocular pressure (IOP) reduction with the same/fewer medications, and IOP between 6 and 18 mmHg. Secondary outcomes were acetazolamide use and success rates per glaucoma type. Safety outcomes were reported as complication rates.

RESULTS

By 24-months, mean IOP reduced from 34.6[±1.4]mmHg to 19.0[ ± 3.0]mmHg post-CW-TSCP (p < 0.0001); and from 26.1[±0.8]mmHg to 19.1[±2.2]mmHg post-MPTLT (p < 0.0001). Average IOP decreased by 45.1% post-CW-TSCP, and 26.8% post-MPTLT. Both interventions reduced medication requirements (p ≤ 0.05). More CW-TSCP patients discontinued acetazolamide (p = 0.047). Overall success rate was 26.6% for CW-TSCP and 30.6% for MPTLT (p = 0.83). Only primary closed-angle glaucoma saw a significantly higher success rate following CW-TSCP (p = 0.014). CW-TSCP complication rate was significantly higher than MPTLT (p = 0.0048).

CONCLUSION

Both treatments significantly reduced IOP and medication load. CW-TSCP had a greater absolute/proportionate IOP-lowering effect, but it carried a significantly greater risk of sight-threatening complications. Further prospective studies are required to evaluate MPTLT compared to CW-TSCP.