Femtosecond laser corneal ablation threshold: dependence on tissue depth and laser pulse width.

Background And Objective: Diode pumped, all-solid-state ultrafast lasers are now widely used to perform minimally invasive refractive surgery and keratoplasty procedures. Despite such use, a systematic study concerning ultrafast laser-tissue interactions is lacking. We determined the corneal ablation threshold as a function of the laser pulse width and stromal depth by simultaneous monitoring of the intensity of the laser-induced plasma and the second harmonic generation signals (SHG) from the collagen.

Age-related structural abnormalities in the human retina-choroid complex revealed by two-photon excited autofluorescence imaging.

The intensive metabolism of photoreceptors is delicately maintained by the retinal pigment epithelium (RPE) and the choroid. Dysfunction of either the RPE or choroid may lead to severe damage to the retina. Two-photon excited autofluorescence (TPEF) from endogenous fluorophores in the human retina provides a novel opportunity to reveal age-related structural abnormalities in the retina-choroid complex prior to apparent pathological manifestations of age-related retinal diseases.

Two-photon excited autofluorescence imaging of human retinal pigment epithelial cells.

Degeneration of retinal pigment epithelial (RPE) cells severely impairs the visual function of retina photoreceptors. However, little is known about the events that trigger the death of RPE cells at the subcellular level. Two-photon excited autofluorescence (TPEF) imaging of RPE cells proves to be well suited to investigate both the morphological and the spectral characteristics of the human RPE cells.