[Panretinal laser photocoagulation with reduced pulse duration--first experience with linear multispot cascades]

VISULAS 532 s VITE is a 532 nm laser device which allows semi-automated photocoagulation in fast cascades with short pulse durations in addition to conventional retinal single-spot coagulation.

In a prospective randomised study 101 peripheral laser treatments for retinopathy of various origins were divided into two groups: control group A (n = 35) coagulation in conventional single-spot modus and study group B (n = 66) coagulation with the new semiautomated VITE-function of VISULAS 532 s. Spot diameter was the same in both groups (300 µm at the retina). Patients were asked about pain immediately after therapy on a scale ranging from 0 ( = no pain) up to 10 ( = maximum pain). From video recording, treatment times were measured. After each treatment, a photo-documentation followed to control the laser effects. The shorter laser pulses in group B were offset by higher laser power to achieve similar moderate effects.

In group A 509 (462-609) effects were set with a pulse duration of 100-150 ms and power of 157 (70-380) mW. 46.0% of the patients complained of pain at an intensity of 4.4 (2-8). The treatment time was 73.4 (61.6 to 103.7) s per 100 effects. In group B 555 (120-600) effects were set with pulse duration of 20 ms and a power of 286 (120-600) mW. 1.3% of the patients complained of pain at an intensity of 3 and 4. The treatment time was 49.4 (24.0-97.5) s per 100 effects. None of the groups experienced complications.

The semiautomated function of the laser using a 20 ms pulse duration allows almost painless coagulation of the retina. The treatment times can be reduced by one third. This leads to improved patient compliance. Long-term results regarding the regression of proliferative changes are still lacking.