Johns Hopkins University

Other

Duke University

Warner Lambert Technologies, Inc.

David Lee Guyton

Boris I Gramatikov

Kristina Irsch

Joseph A Izatt

Cynthia A Toth

David George Hunter

Robert L Fry

Aaron Wang

Oscar M Carrasco-Zevallos

Morey H Waltuck

Jing Tian

Kurt Simons

Robert Geary

John Avallone

Howard S Ying

Julie Christine Sandruck

Saurabh Navinchandra Patel

An eye alignment monitor and method are described for the detection of variability of the relative alignment of the two eyes with each other, thereby detecting deficits of binocular function, for use as a screening device for these abnormalities especially in infants and young children. Each embodiment includes means for tracking of the positions of a subject's two eyes simultaneously, and furthermore includes repetitive calculation of the relative positions of the two eyes with respect to each other. The embodiments do not require fixation by either eye on a specific point. Typically, a movie on a video display is used for viewing by the subject. Variability of relative alignment of the two eyes with each other is typically determined by variability of the relative positions of images of the pupils of the eyes with respect to each other over time.

Eye alignment monitor and method

The present invention provides for very fast detection of gaze direction using retro-reflected light from the ocular fundus that is cost-efficient, small, and portable. These eye trackers are useful in many areas of science and technology, including but not limited to remote control, space, defense, medical and psycho-physiological applications, to identify for example subtle neurologic deficits that occur with cerebellar or vestibular disorders, Parkinson's disease, strokes, traumatic brain injury, possible concussions during sports matches, some forms of reading disability, or simply fatigue or inebriation. In ophthalmology, with two such devices operating simultaneously, the variability of relative eye alignment over time can be measured, without requiring individual calibration, and without requiring fixation on a specified target, ideal for use with small children. Such instruments have widespread application as noninvasive screening devices in infants and young children or patients of any age for defects of binocular function such as strabismus and amblyopia.

Fast X-Y axis bright pupil tracker

The present invention is directed to an indirect ophthalmoscopic system for imaging of the ocular fundus including a headband configured to hold a digital imaging device and a plus eyepiece lens in front of an eye of the examiner, with the plus eyepiece lens positioned in between the digital imaging device and the examiner's eye, such that the examiner is focused upon the display of the digital imaging device. The aperture of the digital imaging device receives light reflected from the ocular fundus of the patient's eye, emanating from the patient's pupil. The examiner examines the patient and composes the image of the ocular fundus directly in the display screen. In this way, what the examiner sees is captured by the digital imaging device. Stereoscopic imagery is obtained by optical means that create side-by-side virtual images of the aperture of the digital imaging device within the pupil of the eye.

Head-mounted indirect opthalmoscope camera

The present invention is directed to a method and system for improved aiming during Optical Coherence Tomography (OCT) on young children and those unable to cooperate with OCT imaging by synchronization with retinal birefringence scanning (RBS). OCT is performed without knowing whether or not the subject is looking at the intended target. The present invention combines OCT retinal imaging, such as, but not limited to, time domain OCT, SDOCT, or SSOCT, with RBS technology that provides accurate information on the presence or absence of foveal fixation. Therefore, the present invention only analyzes data during foveal fixation. A system combining OCT with RBS is implemented such that both systems co-operate in a specified alignment, such that when the RBS fixation detection system detects alignment with the fovea of the eye, the OCT system will be aimed at the retinal region of interest, usually but not necessarily including the macular area.

Method and system for improving aiming during optical coherence tomography on young children by synchronization with retinal bifringence scanning

An eye tracking and gaze fixation detection system, includes an electronically scannable optical illumination system emits polarized near-infrared (NIR) light to a retina in an eye of a subject; an optical detection system arranged in an optical path of the NIR light after being reflected from the retina of the eye of the subject, the optical detection system providing a detection signal; and a signal processing system communicates with the optical detection system to receive the detection signal, wherein the optical illumination system emits the polarized NIR light to illuminate at least a portion of a scanning path, wherein the scanning path is a spatially closed loop across a portion of the retina in the eye of the subject that repeats periodically over time, and wherein the signal processing system is configured to determine at least one of a gaze direction and a gaze fixation based on the detection signal.

Eye tracking and gaze fixation detection systems, components and methods using polarized light

The present invention provides apparatus and methods for detecting fixation of an eye of a subject on a target. The methods provide for optimization of parameters of the spinning half wave plate and the fixed wave plate in the retinal birefringence scanning (RBS) design to enable uses of the 'spinning artifact' frequency component. Frequency of the 'spinning artifact' component is determined by half wave plate rotation speed and direction. Amplitude is determined by interaction of the spinning half wave plate with any retardance encountered in the double-pass optics such as the fixed wave plate, corneal birefringence, and small amount of retinal birefringence. With optimum selection of fractional spinning frequency of the half wave plate, and the orientation/retardance of the fixed wave plate, the &#x201c;spinning artifact&#x201d; frequency component is essentially independent of fixation direction and is also essentially independent of the normal range of corneal birefringence.

Apparatus and method for minimizing the influence of corneal birefringence on the analysis of eye fixation and focus using retinal birefringence scanning

An apparatus for detecting fixation of at least one eye of a subject on a target includes an optical illumination system, an optical detection system, and a signal processing system adapted to communicate with the optical detection system. The signal processing system is configured to calculate at least one of a time-frequency distribution or an Auto-Regressive spectral estimation of the detection signal to provide a frequency distribution of the detection signal at a plurality of times for use in determining periods in which the subject's eye is fixed on the target based on the first and second frequency signatures.

Method and apparatus for detecting fixation of at least one eye of a subject on a target

Apparatus and method are provided for assessing the direction of fixation of an eye by detecting polarization-related changes in light retroreflected from the fundus of the eye. Nerve fibers in the retina of the eye are birefringent and alter the polarization state of light traversing them as a function of their orientation. The nerve fibers are arrayed in a characteristic pattern in the retina, specifically radiating outward from the fovea and converging to the optic nerve head. By assessment of polarization-related changes in rctroreflected light from multiple retinal areas either sequentially or simultaneously, characteristic birefringence signatures of portions of the retina can be identified which are used to assess the direction of fixation of the eye. In addition, interference from the corneal birefringence is reduced by using incident light having a polarization state that is substantially independent of meridional direction. Circularly polarized light or non-polarized light is used for the assessment. Interference from the corneal birefringence is reduced still further by detecting polarization-related changes that are substantially independent of the meridional direction of the corneal birefringence. This is accomplished by detecting changes in ellipticity by measuring solely the Stokes parameter S.sub.3 or by measuring any two Stokes parameters. An alternative is measuring the overall intensity of the retroreflected light when the dichroism of the lutein pigment particles in the vicinity of the fovea is used for the assessment.

Eye fixation monitor and tracker

In order to determine the visual acuity in the human eye in the presence of cataracts or other opacities, a conventional slit lamp microscope having an illumination source, an aperture illuminated thereby, and a converging lens, has been modified by the insertion of a target transparency having test figures thereon between the aperture and converging lens. The inclusion of a set of trial lenses positioned adjacent to the eye to neutralize refractive error, movement axially of the target transparency, and the inclusion of a telescopic optical system also axially adjustable is contemplated.

Apparatus for determination of potential visual acuity utilizing a slit

In apparatus for determining the refractive correction for a patient's eye, a plurality of similar test targets are presented to the patient simultaneously, with these test targets being viewed through different trial refractive corrections for the patient to choose between. Magnification differences produced by the different trial refractive corrections are compensated for by altering the size or shape of the different test targets, such that when magnified by the respective trial refractive correction, each test target appears of normal size and shape to the patient, not interfering with the patient's judgment of best clarity.

Ophthalmic test apparatus having magnification compensation

In an ophthalmic refractor system for determining cylinder power and direction of axis for visual correction, cylinder axis orientation based upon corrective cylinder power in the refractor viewing path is automatically determined and introduced into the system.

Control means for optical instrumentation

An improved method is disclosed for determining the refractive correction for an eye. The method is an improvement over the method described by W. E. Humphrey in his U.S. Pat. No. 3,947,097. The improved method uses apparatus having only one variable astigmatic sub-system to achieve the same optical effects for which Humphrey specifically requires apparatus having two separate variable astigmatic sub-systems. The apparatus used is well-known in the art and includes variable spherical optics in combination with variable astigmatic optics, said variable astigmatic optics being equivalent to a rotatable, variable-power cross cylinder. Two stationary straight line targets, oriented in meridians substantially 45.degree. from one another are alternately focused by the patient. To focus each straight line target the patient adjusts separately both sphere power and cross cylinder. Whenever the cross cylinder is adjusted, both the orientation and the power of the cross cylinder change as necessary to maintain constant the dioptric power of the cross cylinder acting in the meridian of the straight line target being focused. In the preferred embodiment of the method, the patient adjusts the orientation of the cross cylinder, and a servo mechanism adjusts the power of the cross cylinder as necessary. In an alternate embodiment, the patient adjusts the power of the cross cylinder, and a servo mechanism adjusts the orientation of the cross cylinder as necessary.

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Baltimore, MD, United States of America

David Lee Guyton