To compare concentration of cytokines in the vitreous of rabbit eyes after photocoagulation using a short-pulse pattern scanning laser (PASCAL) or a conventional laser.

Laser photocoagulation was performed using PASCAL (duration 0.02 seconds) in the right eyes and a conventional laser (duration 0.1 seconds) in the left eyes of 13 pigmented rabbits. To obtain ophthalmoscopically similar mild burns, power was adjusted during the photocoagulation. The rabbits were sacrificed at 1, 3 or 7 days after photocoagulation to investigate histological changes. Levels of interleukins (IL)-1β, IL-6, IL-8 and tumor necrosis factor (TNF)-α in the vitreous humors of ten rabbits were measured using enzyme-linked immunosorbent assay before treatment and at 1, 3 and 7 days after photocoagulation.

Histological changes were comparable between the two groups. IL-1β and TNF-α were not detectable. IL-6 did not change significantly. IL-8 increased at day 3 and day 7, but no significant difference was observed between the two groups ( p >0.05).

When ophthalmoscopically similar mild burn intensity was achieved, conventional and PASCAL treatments of rabbit eyes caused no difference in intravitreal concentration of inflammatory cytokines.