Polarimetric high-resolution confocal scanning laser ophthalmoscope

Laboratorio de Optica, Departamento de Física, Universidad de Murcia, Campus de Espinardo (Edificio C), Spain.
Vision Research (Impact Factor: 1.82). 01/2006; 45(28):3526-34. DOI: 10.1016/j.visres.2005.08.008
Source: PubMed


A polarimetric high-resolution confocal scanning laser ophthalmoscope has been developed. The system incorporates a fixed linear polarizer in the illumination path and a rotatory quarter-wave plate and another fixed linear polarizer in the registration path. Retinal areas that are smaller than those provided by commercial instruments can be imaged. Series of four fundus images for independent polarization states in the second pass were recorded for different eyes and retinal locations and the spatially resolved Stokes vectors calculated. From those images, the contrast across retinal blood vessels was maximized and the corresponding image was reconstructed. In terms of polarization, the analysis of small retinal areas might prove to be useful in the improvement of retinal imaging and the enhancement of structural details in the early diagnosis of ocular pathologies.

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Available from: Juan M Bueno,
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    • "The DOP values shown in this work ranged between 0.10 and 0.82. These are similar to those values reported for other retinal areas (Bueno and Vohnsen, 2005) and they lie in the upper range of the values reported by Naoun et al. (2005). Most participants involved in the present study were younger than those involved in Naoun et al.Õs experiment. "
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    ABSTRACT: The degree of polarization (DOP) of the light reflected from the optic nerve head has been assessed by means of a polarimetric scanning laser ophthalmoscope as a function of the age of the participants. Four fundus images corresponding to independent polarization states in the recording pathway were used to compute the spatially-resolved DOP. This was not uniform across the optic nerve head and depended on both the location and the participant's age. Along a peripapillary annulus the DOP followed a double-peak pattern. Moreover, the values along this annulus decreased significantly with increasing age. This depolarization appears to originate in part in the retinal nerve fiber layer. Detailed age-dependent knowledge of the ocular depolarization properties may help to improve clinical diagnosis of the retinal nerve fiber layer.
    Ophthalmic and Physiological Optics 06/2009; 29(3):247-55. DOI:10.1111/j.1475-1313.2009.00644.x · 2.18 Impact Factor
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    • "The statistics of the SH photon count gives additional insight and may be of value for posterior image processing. It is possible to quantify the image contrast in terms of a global root-mean-square (RMS) contrast for each image (Bueno & Vohnsen, 2005). All images (Fig. 5 "
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    ABSTRACT: The ex vivo cornea of porcine eyes has been studied with second-harmonic microscopy with a laboratory-built system to examine the structure of collagen fibrils at different length scales, as well as the image dependence on polarization and wavelength of the illumination source. We found that collagen fibrils can effectively be visualized with second-harmonic microscopy, in agreement with previous findings, at different wavelengths of the illumination. The same laser source used for imaging may also be used to induce changes to the corneal tissues that are observable both in the linear and second-harmonic imaging channels. Such studies are essential first steps towards a future high-resolution optical characterization technique for simultaneous corneal surgery and wound healing of the human eye.
    Journal of Microscopy 11/2008; 232(1):158-63. DOI:10.1111/j.1365-2818.2008.02086.x · 2.33 Impact Factor

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