Photoablation of inner limiting membrane and inner retinal layers using the Erbium:YAG‐laser: An in vitro study

Abstract

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.

Characterization of novel microsphere chain fiber optic tips for potential use in ophthalmic laser surgery

“…13,[17][18][19][20][21][22][23] However, our contact-mode mid-IR microsphere scalpel can create spatially small ablation craters below the limit of current intraocular fiber delivery systems, while using a less powerful laser source. Sapphire microspheres with a refractive index of 1.71, used as lenses, focus laser light at the sphere's surface, creating a robust contact laser device whose performance is unaffected by the transmission medium.…”

“…Previous studies using the Er:YAG laser during vitrectomy procedures have been reported by D'Amico, Joseph, and Hoerauf. 13,[18][19][20][21][22][23] These studies did not use contact probes but fibers and devices at varying distances from retinal and membrane tissue with spot sizes greater than 100 μm.…”

Application of Ultrafast Laser Optoperforation for Plant Pollen Walls and Endothelial Cell Membranes

“…The thickness of the ILM is thinnest at the fovea region of the retina. However, the thickness is larger at the posterior pole of retina (Hoerauf et al, 2006). Furthermore, the ILM is also present over the retinal blood vessels.…”

Detachable microsphere scalpel tips for potential use in ophthalmic surgery with the erbium:YAG laser

“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]32 However, our contact mode mid-IR microsphere scalpel can create spatially small ablation craters below the limit of current intraocular fiber delivery systems, while using a less powerful laser source. Sapphire microspheres with a refractive index of 1.71, used as lenses, focus laser light at the sphere's surface creating a robust contact laser device where the transmission medium will not affect the device's performance.…”

“…Over 20 years ago, the erbium:YAG laser was identified as a promising candidate for precise surgery [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] due to strong water absorption in soft tissues at its emission wavelength of λ ¼ 2.94 μm. However, this laser did not gain widespread acceptance in vitreoretinal surgery due to its relatively large size, slow rate of tissue cutting, and necessity for bulky and exotic flexible mid-infrared (IR) delivery systems.…”