US 5,220,361 AGranted

Gaze tracking for field analyzer

AssigneeAllergan Humphrey

InventorsDonald E. Lehmer, Alan R. Kirschbaum

Life of this patent

Estimating the term…

Loading patent…

Abstract

A field test apparatus is disclosed which is interactive both in the automated positioning of trial lenses (used to correct the patient's focal distance to the tester hemispherical projection screen) as well as providing automatic gaze direction determination through automated video surveillance of the patient's eye. A moveable trial lens holder is provided. This trial lens holder is remotely moveable horizontally and vertically and carries light sources for illuminating the eye preferably in the infrared spectrum at oblique angles preferably towards the center of the eye from the periphery of the trial lens holder. In the gaze direction determination system, a gaze direction determination infrared source--preferably on the surface of the screen near the center of the screen--generates a gaze direction determination reflection on the cornea of the eye--this reflection being near the apex of a normal spherical cornea. At the same time, provision for the automated video measurement of the center of the eye pupil is provided--preferably including measuring a horizontal chord of the eye pupil, bisecting this horizontal chord, locating the bottom of the eye pupil along the bisected dimension, and thereafter finding the pupil center. The relative position of the gaze direction determination reflection from the cornea and the center of the pupil is necessarily related to the direction of gaze of the eye. This relative position is compared to the relative position that the patient initially had when properly fixated. Change in this comparison value is utilized to indicate a change in gaze direction.

Claims33

Dependent claims

In a field test apparatus for monitoring the field of retinal vision of an eye of a patient by projecting light images of variable intensity peripherally to a line of sight along which patient fixation of said eye occurs, said field test apparatus comprising:

a fixation source for view by said eye of said patient along said line of sight;
a screen mounted about said fixation source for receiving the projection of light forming said images, said screen centered about said line of sight to enable said eye of said patient fixating along said line of sight at said fixation source to peripherally view images of varying intensity projected to said screen for mapping of the optical sensitivity of a retina of said eye;
means for recording patient indication of said view of said images of said point of light responsive to input from said patient;
means for projecting said images of varying intensity at known different variable placements to said screen relative to said line of sight for measurement of the retinal field of view of said eye of said patient;
means for holding at least one trial lens in front of said patient at the eye of said patient undergoing test;
means for resting a portion of a head of said patient with the eye of said patient proximate to an intersection with said line of sight and said means for holding at least one trial lens;
means for video monitoring of said patient mounted to said screen for providing a video view of the eye of said patient along an axis;
means for dark eye illumination of said eye of said patient including a light source illuminating said eye from a position off center with respect to said axis of said means for video monitoring of said eye;
a gaze direction determination source mounted to said screen for producing on said cornea of said eye a reflection which is a function of the position of said cornea of said eye relative to said line of sight;
means for processing of said video image at a pupil of eye for locating the center of the pupil of said eye and outputting a first signal and outputting a second signal relating to the position of said reflection of said gaze direction determination source in said eye wherein said means for processing said video image includes;
means for measuring a horizontal chord across the pupil of said eye;
means for measuring the vertical distance between a center point on said horizontal chord and the bottom of said pupil of said eye;
and,
means for determining the center of the pupil of said eye relative to said measured chord and said vertical distance between the center of said chord and said bottom of said pupil of said eye;
and,
means for comparing said first and second signals and outputting a composite signal related to the direction of gaze of said eye whereby said output changes are a function of eye fixation.

13 more elements

In a field test apparatus for monitoring the field of retinal vision of an eye of a patient by projecting light images of points of light of variable intensity peripherally to a line of sight along which patient fixation of said eye occurs, said field test apparatus including:

a fixation light source emitting light in a visible spectrum for view by said eye of said patient along said line of sight;
a screen mounted about said fixation source for receiving the projection of light forming said images of points of light, said screen centered about said line of sight to enable said patient at said eye fixating along said line of sight at said fixation source to peripherally view images of said points of light of varying intensity projected to said screen for mapping of the optical sensitivity of an eye's retina;
means for recording said patient's indication of said view of said images of said points of light responsive to input from said patient;
means for projecting said images of points of light of varying intensity at controlled variable placements to said screen relative to said line of sight for measurement of the retinal field of view of said eye of said patient;
means for holding at least one trial lens in front of said patient at the eye of said patient;
means for resting a portion of a head of said patient with the eye of said patient proximate to an intersection with said line of sight and said means for holding at least one trial lens;
and
means for video monitoring of said patient mounted to said screen for providing a video view of the eye of said patient;
the improvements to said means for holding and said means for video monitoring comprising:
means for comparing the position of a pupil in said video view of said eye of said patient to the position of said trial lens to output the relative displacement between center of the pupil of said patient and said means for holding at least one trial lens, said means outputting a signal responsive to said relative displacement;
and
means for moving said means for holding at least one trial lens responsive to said detected relative displacement to maintain a constant relative displacement between the center of said pupil of said patient and said trial lens.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/710,722Filed 5 Jun 1991
Granted: 15 Jun 1993
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G06V 40/19
Eye characteristics, e.g. of the iris: sensors therefor
A61B 3/024
Subjective types, i.e. testing apparatus requiring the active assistance of the patient: for determining the visual field, e.g. perimeter types
G02C 13/003
Assembling ; Repairing; Cleaning: measuring during assembly or fitting of spectacles
G02C 13/005
Measuring during assembly or fitting of spectacles: measuring geometric parameters required to locate ophtalmic lenses in spectacles frames