Investigation of gold-coated bare fiber probe for in situ intra-vitreous coherence domain optical imaging and sensing.

We have investigated the usage of gold-plated bare fiber probes for in situ imaging of retinal layers and surrounding ocular tissues using time-domain common-path optical coherence tomography. The fabricated intra-vitreous gold-plated micro-fiber probe can be fully integrated with surgical tools working in close proximity to the tissue to provide subsurface images having a self-contained reference plane independent to the Fresnel reflection between the distal end of the probe and the following medium for achieving reference in typical common-path optical coherence tomography. We have fully characterized the probe in an aqueous medium equivalent to the vitreous humor in the eye and were able to differentiate various functional retinal tissue layers whose thickness is larger than the system's resolution.

A simple confocal fibre-optic laser method for intraocular lens power measurement.

PURPOSE: To develop novel confocal fibre-optic laser method (CFOLM) for accurate and objective measuring of the dioptric power of both positive and negative intraocular lenses (IOLs). METHODS: The CFOLM principle of operation is based on a simple apertureless single-mode fibre laser confocal design. The key element is a single-mode fibre coupler that serves simultaneously as a point light source (3-5 microm fibre diameter) used for the formation of a collimated Gaussian beam, and as a confocal point receiver that is highly sensitive to spatial displacements of the focused backreflectance laser emission. The basic CFOLM systems include IOL testing set-ups for the measurement of both positive and negative IOLs. RESULTS: The CFOLM designs provide high accuracy (

Characterizing reflections from intraocular lens implants.

OBJECTIVE: To develop a test method for characterizing glare from intraocular lenses (IOLs) and to confirm a clinical finding that the haptic insertion in the optic of a three-piece IOL produces extraneous line images. METHOD: The method consists of directing a collimated Gaussian laser beam to various parts of the IOL to be tested in a water-filled model eye. Reflected images produced in the retinal plane are photographed with a digital camera. RESULTS: A test method was developed to characterize the source of glare images from IOLs. The test method developed was used to confirm a clinical finding that the haptic insertion in the optic of a three-piece IOL produces extraneous line images. CONCLUSIONS: The method developed can be used to characterize and pin point the source of extraneous glare images from intraocular lens implants. The haptic insertion in the optic of a three-piece IOL has been identified as a source of line images.

Attenuation measurement of infrared optical fibers by use of a hollow-taper-based coupling method.

An alternative method for attenuation measurement of infrared (IR) fibers is described. The method includes a simple technique for direct laser-to-fiber coupling with an uncoated glass hollow taper. The operating principle of the hollow taper is based on the grazing-incidence effect of light reflection. The hollow taper forms a smooth Gaussian-shaped profile of the output laser emission and provides the proper conditions for equilibrium-mode distribution of optical power within the test IR fibers. The experimental hollow-taper-based coupling method is used for measurement of attenuation and bending losses of various kinds of IR fiber, including solid-core (fluoride, chalcogenide, and germanium-doped) and hollow fibers.

Simple fiber-optic autocollimation method for determining the focal lengths of optical elements.

A novel simple fiber-optic autocollimation method for determining the focal lengths of lenses and objectives is presented. This method is based on the intensity sensing of reflected light, photoelectric measurement, and the use of single-mode optical fiber. This fiber serves simultaneously as a point light source for the formation of a collimated input laser beam and as a receiver that is highly sensitive to spatial displacements for the autocollimation backreflectance. The method permits us to locate the focal point spatially and to determine the back focal length of a focusing optical element with accuracies exceeding 1 and 2 microm, respectively, which are confirmed by both experimental and analytical investigations.

Simple autocollimation laser refractometer with highly sensitive, fiber-optic output.

A simple autocollimation scheme for a laser refractometer with a highly sensitive, single-mode, fiber-optic output is described. It allows for the determination of the refractive index and dispersion of optical materials with an accuracy exceeding 10(-5), which is confirmed by both experimental and analytical investigations.