Evaluation of Diffuse Reflectance Spectroscopy Vegetal Phantoms for Human Pigmented Skin Lesions.

Pigmented skin lesions have increased considerably worldwide in the last years, with melanoma being responsible for 75% of deaths and low survival rates. The development and refining of more efficient non-invasive optical techniques such as diffuse reflectance spectroscopy (DRS) is crucial for the diagnosis of melanoma skin cancer. The development of novel diagnostic approaches requires a sufficient number of test samples.

In-vivo measurement of the fluorescence spectrum of wild cochineal (Dactylopius opuntiae).

It is known that the harmful presence of the wild cochineal (Dactylopius opuntiae), unlike the fine cochineal (Dactylopius coccus), in prickly pear crops of farmers leads to consider it as one of the major pests for this crop. In this study, we present the implementation of an optical setup that ensures the measurement of the in-vivo fluorescence spectra of wild cochineals ranging in size from 440 to 1190 µm in their natural habitat achieved by developing a reproduction model adopted from available literature. It was observed that in-vivo fluorescence spectra of these insects were comprised in the spectral region of 570-760 nm, showing a proportional dependence between the fluorescence intensity emitted and the cochineal size.

Simulation and analysis of light scattering by multilamellar bodies present in the human eye.

A modified computational model of the human eye was used to obtain and compare different probability density functions, radial profiles of light pattern distributions, and images of the point spread function formed in the human retina under the presence of different kinds of particles inside crystalline lenses suffering from cataracts. Specifically, this work uses simple particles without shells and multilamellar bodies (MLBs) with shells. The emergence of such particles alters the formation of images on the retina.

Aspheric lens to increase the depth of focus.

For high-resolution optical systems, a long depth of focus is desirable. Unfortunately, resolution and depth of focus are inversely related. In this work, a novel lens is presented to produce long depth of focus beams, keeping the same resolution.

Computational model of the effect of light scattering from cataracts in the human eye.

A model of the human eye has been developed, including scattering from cataracts inside the nucleus of the lens. The cataracts are modeled as spherical particles with refractive index different from that of the surrounding lens medium. Scattering from the retina is also included in the simulations.