Subthreshold Photocoagulation Using Endpoint Management in the PASCAL® System for Diffuse Diabetic Macular Edema

Abstract

We evaluated subthreshold photocoagulation using endpoint management (EPM) for the treatment of diabetic macular edema (DME). The study enrolled 10 eyes from 10 patients (6 men and 4 women) with DME. The entry criteria included central macular thickness (CMT) ≥ 300 μm and decimal visual acuity (VA) ≤ 0.5. The primary endpoints were VA (logMAR) and CMT at 6 months follow-up. Secondary endpoints included fundus autofluorescence, macular volume (MV), and macular sensitivity (MS). We used the PASCAL Streamline Yellow® (wavelength, 577 nm) system to perform grid pattern laser photocoagulation at 50% of the threshold (size, 100 μm; duration, 0.015 s; spacing, 0.5; and energy, 4.5–7.8 mJ). At 6 months posttreatment, CMT was significantly decreased, while there were no significant changes in macular sensitivity, mean BCVA (logMAR), or macular volume. Autofluorescence imaging revealed no changes after treatment in 6 of 10 eyes. No eyes exhibited subjective symptoms of scotoma after photocoagulation. Optical coherence tomography showed the complete resolution of macular edema in 4 eyes (40%) after a single treatment; MS was increased in all 4 of these eyes at 6 months posttreatment. In conclusion, subthreshold photocoagulation using EPM is safe and effective for DME treatment and preserves MS. This trial is registered with UMIN000012401.

Stellungnahme der DOG, der RG und des BVA zur Therapie des diabetischen Makulaödems

“…Mit unterschwelligen Laserverfahren ist die Hoffnung verbunden, das Ausmaß an sekundärer Atrophie mit Skotomen und späterer Vergrößerung der Läsionen zu verringern [247]. Das Subthreshold-System von PASCAL (Topcon, AC Capelle a/d IJssel, Niederlande) strebt über eine kürzere Pulsdauer (10-30 ms) eine Reduktion der Leistung an [248]. Die Mikropulstechnologie fragmentiert die Laseremission in eine Folge von kurzen, sich wiederholenden Mikrosekundenimpulsen [249].…”

Application of subthreshold laser therapy in retinal diseases: a review

“…One of the most recent advances in 577 nm laser therapy of DME, the automated PASCAL system, was found to be safe in an uncontrolled prospective trial of 10 eyes[13]. Indeed, the PASCAL endpoint management system affords the advantage of automatic determination of subthreshold laser energy, thus abrogating the need for titrating laser power during treatment[13].…”

“…Micro[11]- and nano-pulse[12] laser settings refer to the duration of light pulse in seconds and are often ST in their effect. While the extent and intensity of ST laser treatment of retinal pathology has traditionally been left to the operating surgeon to adjust manually, often by using a supra-threshold test spot in the retinal periphery, another approach has been an automated calculation of determining the optimal ST intensity and pattern of laser application through software[13].…”

Novel Retinal Laser Therapies

“…This provides an approach to provide reproducible subvisible retinal laser therapy. As illustrated in several small clinical trials, subthreshold photocoagulation using PASCAL treatment with endpoint management software have provided significant beneficial effects to patients who suffer from CSCR and DME (Figure 3) [51,52] .…”