Glaucoma represents the second leading cause of blindness worldwide. While both age and intraocular pressure (IOP) are well-recognized risk factors for this disease, the underlying pathologic process involves the accelerated death of retinal ganglion cells (RGCs) that is associated with progressive loss of vision. The loss of RGCs has been postulated to occur primarily by injury to axons in the optic nerve head (ONH) due to its anatomic features and the mechanical vulnerability of the lamina cribrosa, the specialized ONH zone comprised of collagen beams that define the channels or pores through which axon bundles exit the eye. Recent advances in multiphoton microscopy using femtosecond lasers that generate second harmonic (SH) signals from collagen allows for direct optical imaging of the lamina cribrosa. We assess the application of SH generated microscopy (SHG) to the study of the ONH, and test the general hypothesis that increasing intraocular pressure in the same eye results in the movement of ONH collagen beams leading to distortion of the lamina cribrosa channels and compression of the axon bundles.

This study suggests that bevacizumab, at concentrations at or above the dose normally used in clinical practice, is not toxic to human retinal pigment epithelial, rat neurosensory retinal, or human microvascular endothelial cells in vitro. This report is consistent with the recent report of lack of toxicity of intravitreal bevacizumab in rabbits as well as the lack of apparent toxicity in clinical use.

Arcuate retinotomy is a new approach that may aide in the repair of large macular holes not otherwise amenable to closure with traditional techniques.

These results show that B(e)P is a toxicant to human retinal pigment epithelial cells in vitro. It causes cell death and induces apoptosis by the involvement of multiple caspase pathways.