Glaucoma experts answer 5 key questions about the clinical application of MicroPulse TLT

An international consensus panel analyzed the clinical, technical, and practical experience to date on use of the MicroPulse Transscleral Laser Therapy (TLT). During a 2-part webinar series, the 10 glaucoma experts discussed key points from their consensus document ranging from safety and effectiveness to surgical technique. Below are 5 of the top questions answered by the panel.

1. Does the amount of laser energy applied effect IOP reduction and the duration of effect? 

Tomas Grippo, MD said that the correct amount of energy to apply to achieve a good balance between outcomes and side effects has been difficult to define.  

Clinical evidence and consensus recommendations suggest that the amount of laser energy applied determines if the effect is achieved and if that effect is reversible or irreversible.

Reduced efficacy and sustainability of the IOP lowering effect are associated with low total energy.

“Increased total energy is associated with a more permanent effect and again, even though this may sound totally logical, you may find recent publications in the literature, where people have been using very low energy settings and therefore have not obtained the expected results,” said Dr Grippo.

2. What parameters should be used to achieve a balance between good efficacy and a good safety profile?

Dr Grippo said that it’s clear that there is not enough evidence or experience yet to provide definitive minimum and maximum settings for the updated probe, but evidence suggests that with an excess of energy there may be a higher prevalence of side effects.

When using the revised MicroPulse P3 probe, the consensus panel suggests starting parameters of 2500 mw, 31.3% duty cycle, and 4 sweeps of 20 seconds each per hemisphere.

3. Should MicroPulse TLT be performed in an office setting or the operating theater?

Although it’s possible to perform MicroPulse TLT in an office setting, most of the panel felt it is better performed in an operating theater due to the preferred use of topical anesthesia plus sedation.

“The decision about whether to use a topical or block anesthesia should be made, based on the anxiety level and general pain tolerance of the patient,” said Marc Toeteberg-Harms, MD, FEBO.

Dr Toeteberg-Harms said his anesthesiologist usually uses fentanyl to control the patient’s pain level as well lower anxiety they may be feeling before the procedure.

4. What are the potential side effects, especially with the revised probe?

Compared to traditional continuous-wave cyclophotocoagulation, Brian Jerkins, MD said he believes MicroPulse LTL is an extremely safe alternative and that many of the complications can be attributed to the use of the old probe and surgical technique.

“With a current better understanding of dosimetry and some of the energy limits that we need to deliver in certain areas, the revised probe allows for a much safer delivery and controlled delivery for a more posterior treatment,” he said.

With the revised probe, Dr Jerkins noted fewer instances of mydriasis, loss of accommodation, cataract formation, dry eye, or general side effects.

5. Should a coupling agent be used? 

Michael Giovingo, MD said he believes a coupling agent is necessary when performing the procedure, with lidocaine gel being the most used one.

The coupling agent should generally be applied over the eye and the probe footplate at the very beginning of the case. Dr Giovingo said the panel was split on whether reapplications were needed, but the group agreed that if they saw the eye drying out during the case, reapplication should be done.

The full webinar can be viewed here.