Comparative Effectiveness and Tolerance of Subliminal Subthreshold Transscleral Cyclophotocoagulation With a Duty Factor of 25% Versus 31.3% for Advanced Glaucoma

Abstract

Précis: Subliminal subthreshold transscleral cyclophotocoagulation (SS-TSCPC) with duty cycles 25% and 31.3% seems to be an effective approach to reduce intraocular pressure (IOP) in glaucoma that is refractory to medical management. Objective: The objective of this study was to compare the effectiveness and the tolerance of SS-TSCPC with a duty cycle of 25% versus 31.3% with Supra 810 nm Subliminal Quantel Medical laser stimulation for advanced glaucoma. Materials and Methods: This was a retrospective, single-center, comparative case series of patients treated by SS-TSCPC between January 2017 and July 2017. The diagnostic and inclusion criteria were patients with advanced and refractory glaucoma, defined as IOP >21 mm Hg on maximal tolerated medical therapy with or without previous glaucoma surgical procedures, a minimum follow-up of 12 months, and patients who refused or were poor candidates for additional filtering surgery or implantation of glaucoma drainage devices. The primary endpoint was surgical success defined as an IOP of 6 to 21 mm Hg or a reduction of IOP by 20% from baseline without an increase in glaucoma medication from baseline. The secondary endpoints were the mean IOP and best visual corrected acuity best-corrected visual acuity at 12 months after surgery, retreatment outcomes, glaucoma medications, and complications such as inflammation, uveitis, cataract, mydriasis, and phthisis. Results: Forty eyes of 32 patients were included: 20 eyes were subjected to SS-TSCPC with 31.3% duty cycle and 20 eyes with a 25% duty cycle. The surgical success of the TSCPC 12 months after the first procedure was better in the 31.3% duty cycle group (83.5%) than in the 25% duty cycle group (65%). The most common complications were inflammation (50%, 1 mo after surgery) and IOP spikes (increase in IOP of >25% from baseline within 1 mo of laser) in both groups. Inflammation was higher in the 31.3% duty cycle group. Conclusions: SS-TSCPC at 31.3% and 25% duty cycle seems to be an effective approach to reduce IOP in glaucoma that is refractory to medical management. SS-TSCPC at 31.3% duty cycle is more effective than the 25% duty cycle SS-TSCPC. However, the 31.3% duty cycle SS-TSCPC induces more inflammation than the 25% duty cycle SS-TSCPC. Each procedure should be considered on a case by case basis.

An update on continuous‐wave cyclophotocoagulation (CW‐CPC) and micropulse transscleral laser treatment (MP‐TLT) for adult and paediatric refractory glaucoma

“…Forty per cent of eyes (4/10) in which UBM was performed showed a fine space between the sclera and the CB, suggesting an increased uveoscleral outflow (Benhatchi et al 2019). In another study, the same team has compared the efficacy and tolerance of the procedure using the same treatment durations (100 s per eye) and powers (2000 mW) but by comparing 2 groups of 20 eyes each according to a duty cycle of 25% or 31.3% (Keilani et al 2020). The surgical success rate 12 months after the first procedure (IOP between 6 and 21 mmHg or an IOP lowering by 20% from baseline with no increase in glaucoma medication from baseline) was higher in the group with a duty cycle of 31.3% (83.5%) than in the group with a duty cycle of 25% (65%).…”

Micropulse Transscleral Cyclophotocoagulation

“…Keilani et al compared 25% duty cycle to 31.3% and found that the latter was more effective but induced more inflammation. 37 …”

The effect of cumulative energy in repeated subliminal transscleral cyclophotocoagulation: a retrospective study

“…The guidelines [ 24 , 27 ] provide a useful collection of evidence-based consensus mainly on the MicroPulse (IRIDEX) machine. On the other hand, data regarding the safety and the efficacy of the Supra 810 and Vitra 810 (Quantel Medical) machines are scarce [ 37 , 39 , 50 , 51 ]. Our results suggest that similar outcomes can be achieved with the Quantel machines, also broadening treatment options.…”

“…Review of the current literature shows that the criteria of success varies on a broad scale from IOP reduction of at least 20% [17,18,20,23,26,28,29,[33][34][35][36][37][38][39], IOP reduction of at least 30% [40][41][42][43], the variations of specific IOP and percentage limits [13,19,21,25,44], all the way to the most stringent criteria by Tekeli and Soussi [30,45]. In our study, the fulfilment of these criteria shows the discrepancy between the high proportion of patients with an IOP reduction of more than 30% (65%) versus the percentage of low target IOPs achieved (13%) with this method alone.…”