Jeffrey L Stewart

Title: Innovations by Jeffrey L. Stewart

Introduction

Jeffrey L. Stewart is a notable inventor based in Greenwich, CT, with a remarkable portfolio of 11 patents. His work primarily focuses on advancements in visual field testing and contrast sensitivity measurement, showcasing his commitment to improving medical technology.

Latest Patents

One of his latest patents is a "Method for establishing fixation employing speech recognition." This invention provides a method for establishing fixation during computerized visual field perimetry. It requires the subject to verbally identify the symbol employed as fixation targets as they appear. Speech recognition techniques are utilized to evaluate the subject's response. Upon correctly identifying the fixation symbol, a visual test stimulus is displayed at a predetermined location within the subject's field of vision. The fixation symbols include geometrical shapes, letters, numbers, pictures, or other symbols readily identifiable by the subject. When a fixation symbol appears, the subject verbally identifies it by saying the name of the symbol into a microphone. The system recognizes the response and evaluates whether the symbol was correctly identified. Upon correct identification, the fixation symbol disappears, and a flashing visual test stimulus is displayed for a preset time.

Another significant patent is the "Method and apparatus for measuring contrast sensitivity." This novel contrast sensitivity test utilizes an adaptive contrast threshold algorithm. It is embodied as a two-alternative forced choice examination using grating stimuli of randomly interleaved spatial frequencies. The stimulus's orientation is either tilted to the left or right of vertical. During the examination, a succession of grating stimuli is presented to the subject, who is asked to indicate the orientation of each stimulus. The contrast level for the next stimulus is varied depending on the subject's response to the previous one using an adaptive weighted up-down algorithm. For each correct response, the contrast level is reduced, while for each incorrect response, it is increased. Importantly, the amount by which the contrast level is lowered differs from the amount by which it is raised, and this amount changes as the examination progresses. A maximum likelihood method is then employed for finding the best estimation of the contrast threshold from the subject's responses to known contrast levels.

Career Highlights

Throughout his career, Jeffrey has contributed to companies such as VisionRx, Inc. and VisionRx.com, Inc. His innovative work has significantly impacted the field of visual testing and measurement.

Collaborations

Jeffrey has collaborated with notable professionals,