Optical sectioning enhancement using higher-order moment signals in random speckle-structured illumination microscopy.

The optical sectioning capability of structured illumination using random speckle patterns is shown by simulations to improve when cumulants beyond the traditional second order are used as the image-forming signals. The improvement scales with the cumulant order, asymptotically approaching confocal performance. As actual experiments operate with finite-size sample estimators instead of true cumulants, purely statistical (nonoptical) effects can result in nonideal behavior.

Thermal analysis of dry eye subjects and the thermal impulse perturbation model of ocular surface.

In this study, we explore the usage of ocular surface temperature (OST) decay patterns to distinguished between dry eye patients with aqueous deficient dry eye (ADDE) and meibomian gland dysfunction (MGD). The OST profiles of 20 dry eye subjects were measured by a long-wave infrared thermal camera in a standardized environment (24 °C, and relative humidity (RH) 40%). The subjects were instructed to blink every 5 s after 20 ∼ 25 min acclimation.

Optical segmentation of unprocessed breast tissue for margin assessment.

Visual and tactual examination of unprocessed breast specimens is the standard for intraoperative surgical margin assessment in the United States. However, this procedure does not provide surgeons or pathologists with microscopic views of the tissue, which makes it difficult to accurately assess margin status or the extent of the disease, especially in non-palpable cases. We use a combination of spectral and polarization macroscopic imaging to optically segment the adipose and collagen tissues thus highlighting regions suspected of containing epithelium in order to facilitate optical microscopy techniques.

Integrated multimodal metrology for objective and noninvasive tear evaluation.

The clinical tests used to assess tear film and diagnose dry eye are invasive and produce results that are different from natural tear characteristics. There is a need to objectively and noninvasively assess tear parameters under controlled environmental circumstances to refine dry eye diagnosis and therapy. We have developed multimodal tear imaging systems integrated in a chamber in which individual environmental factors can be precisely varied to investigate their impacts on tear parameters.

Noninvasive, objective, multimodal tear dynamics evaluation of 5 over-the-counter tear drops in a randomized controlled trial.

Purpose: To assess the ability of a noninvasive, objective, multimodal system to compare the efficacy and optical quality of 4 different groups of 5 over-the-counter tear drops.

Methods: Wavefront sensing and optical coherence tomography (OCT) were used to objectively assess visual quality and tear volume, respectively, after the over-the-counter tear drops [2 polyethylene glycol (PEG)-400, 1 carboxymethyl cellulose (CMC), 1 polyvinyl alcohol/PEG-400 (PVA), and 1 glycerine/polysorbate-80] were administered to 23 patients with aqueous-deficient dry eye in a randomized, controlled, double-masked trial. Measurements at each of the 5 visits were taken from both eyes at baseline and 5, 20, and 40 minutes after drop instillation.

Micrometer axial resolution OCT for corneal imaging.

An optical coherence tomography (OCT) for high axial resolution corneal imaging is presented. The system uses 375 nm bandwidth (625 to 1000 nm) from a broadband supercontinuum light source. The system was developed in free space to minimize image quality degradation due to dispersion.

Near-IR fluorescence and reflectance confocal microscopy for imaging of quantum dots in mammalian skin.

Understanding the skin penetration of nanoparticles (NPs) is an important concern due to the increasing presence of NPs in consumer products, including cosmetics. Technical challenges have slowed progress in evaluating skin barrier and NP factors that contribute to skin penetration risk. To limit sampling error and other problems associated with histological processing, many researchers are implementing whole tissue confocal or multiphoton microscopies.

Confocal microscopy of unfixed breast needle core biopsies: a comparison to fixed and stained sections.

Background: Needle core biopsy, often in conjunction with ultrasonic or stereotactic guided techniques, is frequently used to diagnose breast carcinoma in women. Confocal scanning laser microscopy (CSLM) is a technology that provides real-time digital images of tissues with cellular resolution. This paper reports the progress in developing techniques to rapidly screen needle core breast biopsy and surgical specimens at the point of care.

Modulation transfer function measurement of scanning reflectance microscopes.

Real-time medical imaging systems such as reflectance confocal microscopes and optical coherence microscopes are being tested in multiple-patient and multiple-center clinical trials. The modulation transfer function (MTF) of these systems at any given time influences the image information content and can affect the interpretation of the images. MTF is difficult to measure in real-time scanning systems when imaging at the Nyquist limit.

Confocal reflectance theta line scanning microscope for imaging human skin in vivo.

A confocal reflectance theta line scanning microscope demonstrates imaging of nuclear and cellular detail in human epidermis in vivo. Experimentally measured line-spread functions determine the instrumental optical section thickness to be 1.7 +/- 0.

Detectability of contrast agents for confocal reflectance imaging of skin and microcirculation.

Confocal reflectance microscopy of skin and other tissues in vivo is currently limited to imaging at the cellular, nuclear and general architectural levels due to the lack of microstructure-specific contrast. Morphologic and functional imaging at specific organelle and microstructure levels may require the use of exogenous contrast agents in small (nontoxic) concentrations, from which weakly backscattered light must be detected in real time. We report an analysis based on Mie theory to predict detectability, in terms of signal-to-background and signal-to-noise ratios, of reflectance contrast agents within skin and microcirculation.

Noninvasive imaging, treatment, and microscopic confirmation of clearance of basal cell carcinoma.

Background: The diagnosis of basal cell carcinoma (BCC) is generally established by skin biopsy followed by tissue preparation and microscopic analysis. Treatment of BCC is often accomplished by surgical excision.

Objective: To confirm the presence of BCC with a noninvasive imaging technique, to treat the patient with a topical immune response modifier, and to confirm the clearance of BCC noninvasively.