James F. King

Measuring lens opacity: combining quasi-elastic light scattering with Scheimpflug imaging system

Two powerful techniques: quasi-elastic light scattering (QELS) and Scheimpflug imaging (SI), are combined to provide simultaneous (within a few seconds) and objective measurements of lens opacity. The sensitivity and performance of the two techniques is evaluated by inducing cold cataract in the lens of a calf eye. The QELS detects the onset of cataractogenesis much earlier while the Scheimpflug imaging system detects it much later.

Early detection of cataract and response to pantethine therapy with non-invasive static and dynamic light scattering

We present static and dynamic light scattering measurements of early onset cataract before opacity is observed and an evaluation of the effectiveness of pantethine on protein aggregation and light scattering.

New clinical instrument for the early detection of cataract using dynamic light scattering and corneal topography

A growing cataract can be detected at the molecular level using the technique of dynamic light scattering (DLS). However, the success of this method in clinical use depends upon the precise control of the scattering volume inside a patients eye and especially during patients repeat visits. This is important because the scattering volume (cross-over region between the scattered light and incident light) inside the eye in a high-quality DLS set-up is very small (few microns in dimension). This precise control holds the key for success in the longitudinal studies of cataract and during anti-cataract drug screening. We have circumvented these problems by fabricating a new DLS fiber optic probe with a working distance of 40 mm and by mounting it inside a cone of a corneal analyzer. This analyzer is frequently used in mapping the corneal topography during PRK (photorefractive keratectomy) and LASIK (laser in situ keratomileusis) procedures in shaping of the cornea to correct myopia. This new instrument and some preliminary clinical tests on one of us (RRA) showing the data reproducibility are described.

Noninvasive evaluation of corneal abnormalities using static and dynamic light scattering

A preliminary study of corneal abnormalities in intact bovine eyes is presented. Twenty-one eyes were treated with chemicals, cotton swabs, and radial and photo-refractive surgeries. Dynamic and static light scattering was performed as a function of the penetration depth into the corneal tissue. Topographical maps of corneal refractive power from untreated and treated corneas were also obtained using videokeratoscopy and results compared. The ultimate aim is to develop the technique of dynamic light scattering (DLS) for clinical applications in early evaluation of corneal complications after laser-assisted in situ keratomileusis (LASIK) surgeries and other corneal abnormalities.

Noninvasive and remote detection of cataracts during space exploration with dynamic light scattering

Outer space is filled with high-energy ionizing radiation. Continuous radiation exposure or slight increase (e.g., due to flares) in it can be hazardous to astronaut health. Therefore cataractogenesis is a possible risk factor. In this paper we apply the sensitive technique of dynamic light scattering to investigate the simulated effects of X-ray exposure to the ocular tissue of non-human animals. An internet web based system integrates photon correlation data and controls the hardware for animal monitoring at a remote site in real time.

Non-invasive, quantitative, and remote detection of early radiation cataracts for applications in bio-astronautics and bio-informatics

Human exploration of Mars may be a possibility in the next twenty years. Maintaining good vision is an essential aspect of achieving a successful mission. Continuous radiation exposure is a risk factor for radiation-induced cataracts in astronauts. A compact device based on the technique of dynamic light scattering (DLS) is designed for monitoring an astronaut’s ocular health during long-duration space travel. Preliminary data on the simulated effects of ionizing radiation exposure to the ocular tissues of non-human animals and results on the sensitivity of DLS over established clinical procedures in investigating cataracts are presented. This capability of early diagnosis, unmatched by any other clinical technique in use today, may enable prompt initiation of preventive/curative therapy. An inter-net web based system integrating photon correlation data and controlling the hardware to monitor cataract development in vivo at a remote site in real time (tele-ophthalmology) is currently being developed. Cata...