MicroPulse® Transscleral Laser Therapy – Fluence May Explain Variability in Clinical Outcomes: A Literature Review and Analysis

Since the first peer-reviewed publication on MicroPulse^® Transscleral Laser Therapy (MP-TLT) in 2010, authors worldwide have used a wide range of treatment parameter combinations with varying clinical efficacy in terms of the magnitude of intraocular pressure reduction, success rate, durability, and safety profile. This has made it difficult to determine the proper parameters necessary to optimize efficacy and safety, and has made comparison of results from one investigation to another difficult. The first goal of this paper is to explain and highlight the impact of the choices of exposure time and the number of sweeps per hemisphere in terms of "sweep velocity" on energy delivery to the eye. These treatment parameters are underreported in the literature. The second goal is to introduce fluence as a "dose" metric, that combines all the treatment parameters and constants into a single number. Fluence may be a better light-dose metric and a more reliable indicator of clinical outcomes compared to total energy.