Background and Objectives: To explore the potential of Er:YAG-laser irradiation for precise and tractionless retinal tissue and inner limiting membrane ablation. Materials and Methods: We used free-running Er:YAGlaser irradiation (l ¼ 2.94 mm) transmitted either through a 10 cm long low-OH-quartz fiber or a 2 m long sapphire fiber that produced a more homogenous light distribution at the fiber tip. Retinal ablation in porcine retinal explants was performed under air or perfluorodecaline (PFD). Ablation depth was evaluated by optical coherence tomography (OCT) and from histologic sections. Results: A radiant exposure of 5.0 J/cm 2 delivered through a low-OH-quartz fiber and PFD caused a complete transsection of the neurosensory retina. Radiant exposures between 3.5 and 2.0 J/cm 2 resulted in marked variations of ablation depth and adjacent thermal damage. By contrast, laser pulses of 4.0 and 3.0 J/cm 2 transmitted through the sapphire fiber produced more homogenous defect patterns and less thermal damage. Close to the ablation threshold, with 1.0-2.0 J/cm 2 , ablation was limited to a 10-20 mm thin layer of the neural retina. Conclusions: We achieved in vitro ablation of inner retinal layers, but could not produce selective and reproducible ILM removal.

The Er:YAG laser system with a low-OH quartz fiber allowed ablation of inner retinal layers in vitro, but revealed a variable ablation depth and low reproducibility.However, a sapphire fiber showed markedly improved results. Therefore its use during vitreoretinal surgery seems possible not only as a cutting device but also as a tool for the ablation of fine retinal structures.