A PC-based shutter glasses controller for visual stimulation using multithreading in LabWindows/CVI

Research output: Contribution to journalArticle

Abstract

Background and objectives: Amblyopia, commonly known as “lazy eye,” is poor vision in an eye from prolonged neurologic suppression. It is a major public health problem, afflicting up to 3.6% of children, and will lead to lifelong visual impairment if not identified and treated in early childhood. Traditional treatment methods, such as occluding or penalizing the good eye with eye patches or blurring eye drops, do not always yield satisfactory results. Newer methods have emerged, based on liquid crystal shutter glasses that intermittently occlude the better eye, or alternately occlude the two eyes, thus stimulating vision in the “lazy” eye. As yet there is no technology that allows easy and efficient optimization of the shuttering characteristics for a given individual. The purpose of this study was to develop an inexpensive, computer-based system to perform liquid crystal shuttering in laboratory and clinical settings to help “wake up” the suppressed eye in amblyopic patients, and to help optimize the individual shuttering parameters such as wave shape, level of transparency/opacity, frequency, and duty cycle of the shuttering. Methods: We developed a liquid crystal glasses controller connected by USB cable to a PC computer. It generates the voltage waveforms going to the glasses, and has potentiometer knobs for interactive adjustments by the patient. In order to achieve good timing performance in this bidirectional system, we used multithreading programming techniques with data protection, implemented in LabWindows/CVI. Results: The hardware and software developed were assessed experimentally. We achieved an accuracy of ±1 Hz for the frequency, and ± 2% for the duty cycle of the occlusion pulses. We consider these values to be satisfactory for the purpose of optimizing the visual stimulation by means of shutter glasses. The system can be used for individual optimization of shuttering attributes by clinicians, for training sessions in clinical settings, or even at home, aimed at stimulating vision in the “lazy” eye. Conclusions: Multithreading offers significant benefits for data acquisition and instrument control, making it possible to implement time-efficient algorithms in inexpensive yet versatile medical instrumentation with only minimum requirements on the hardware.

Original languageEnglish (US)
Pages (from-to)151-158
Number of pages8
JournalComputer Methods and Programs in Biomedicine
Volume143
DOIs
StatePublished - May 1 2017

Fingerprint

Photic Stimulation
Glass
Amblyopia
Liquid crystals
Liquid Crystals
Controllers
Knobs
Hardware
Data privacy
Opacity
Public health
Medical problems
Transparency
Computer Security
Social Adjustment
Data acquisition
Cables
Ophthalmic Solutions
Vision Disorders
Computer Systems

Keywords

  • Amblyopia
  • Liquid crystal shutter
  • Multithreading
  • Shutter glasses
  • Thread-safe queues

ASJC Scopus subject areas

  • Software
  • Computer Science Applications
  • Health Informatics

Cite this

@article{5f5b0d1742164e068d1eafa9b57acd0e,
title = "A PC-based shutter glasses controller for visual stimulation using multithreading in LabWindows/CVI",
abstract = "Background and objectives: Amblyopia, commonly known as “lazy eye,” is poor vision in an eye from prolonged neurologic suppression. It is a major public health problem, afflicting up to 3.6{\%} of children, and will lead to lifelong visual impairment if not identified and treated in early childhood. Traditional treatment methods, such as occluding or penalizing the good eye with eye patches or blurring eye drops, do not always yield satisfactory results. Newer methods have emerged, based on liquid crystal shutter glasses that intermittently occlude the better eye, or alternately occlude the two eyes, thus stimulating vision in the “lazy” eye. As yet there is no technology that allows easy and efficient optimization of the shuttering characteristics for a given individual. The purpose of this study was to develop an inexpensive, computer-based system to perform liquid crystal shuttering in laboratory and clinical settings to help “wake up” the suppressed eye in amblyopic patients, and to help optimize the individual shuttering parameters such as wave shape, level of transparency/opacity, frequency, and duty cycle of the shuttering. Methods: We developed a liquid crystal glasses controller connected by USB cable to a PC computer. It generates the voltage waveforms going to the glasses, and has potentiometer knobs for interactive adjustments by the patient. In order to achieve good timing performance in this bidirectional system, we used multithreading programming techniques with data protection, implemented in LabWindows/CVI. Results: The hardware and software developed were assessed experimentally. We achieved an accuracy of ±1 Hz for the frequency, and ± 2{\%} for the duty cycle of the occlusion pulses. We consider these values to be satisfactory for the purpose of optimizing the visual stimulation by means of shutter glasses. The system can be used for individual optimization of shuttering attributes by clinicians, for training sessions in clinical settings, or even at home, aimed at stimulating vision in the “lazy” eye. Conclusions: Multithreading offers significant benefits for data acquisition and instrument control, making it possible to implement time-efficient algorithms in inexpensive yet versatile medical instrumentation with only minimum requirements on the hardware.",
keywords = "Amblyopia, Liquid crystal shutter, Multithreading, Shutter glasses, Thread-safe queues",
author = "Ivan Gramatikov and Simons, {Kurt A.} and Guyton, {David Lee} and Boris Gramatikov",
year = "2017",
month = "5",
day = "1",
doi = "10.1016/j.cmpb.2017.03.008",
language = "English (US)",
volume = "143",
pages = "151--158",
journal = "Computer Methods and Programs in Biomedicine",
issn = "0169-2607",
publisher = "Elsevier Ireland Ltd",

}

TY - JOUR

T1 - A PC-based shutter glasses controller for visual stimulation using multithreading in LabWindows/CVI

AU - Gramatikov, Ivan

AU - Simons, Kurt A.

AU - Guyton, David Lee

AU - Gramatikov, Boris

PY - 2017/5/1

Y1 - 2017/5/1

N2 - Background and objectives: Amblyopia, commonly known as “lazy eye,” is poor vision in an eye from prolonged neurologic suppression. It is a major public health problem, afflicting up to 3.6% of children, and will lead to lifelong visual impairment if not identified and treated in early childhood. Traditional treatment methods, such as occluding or penalizing the good eye with eye patches or blurring eye drops, do not always yield satisfactory results. Newer methods have emerged, based on liquid crystal shutter glasses that intermittently occlude the better eye, or alternately occlude the two eyes, thus stimulating vision in the “lazy” eye. As yet there is no technology that allows easy and efficient optimization of the shuttering characteristics for a given individual. The purpose of this study was to develop an inexpensive, computer-based system to perform liquid crystal shuttering in laboratory and clinical settings to help “wake up” the suppressed eye in amblyopic patients, and to help optimize the individual shuttering parameters such as wave shape, level of transparency/opacity, frequency, and duty cycle of the shuttering. Methods: We developed a liquid crystal glasses controller connected by USB cable to a PC computer. It generates the voltage waveforms going to the glasses, and has potentiometer knobs for interactive adjustments by the patient. In order to achieve good timing performance in this bidirectional system, we used multithreading programming techniques with data protection, implemented in LabWindows/CVI. Results: The hardware and software developed were assessed experimentally. We achieved an accuracy of ±1 Hz for the frequency, and ± 2% for the duty cycle of the occlusion pulses. We consider these values to be satisfactory for the purpose of optimizing the visual stimulation by means of shutter glasses. The system can be used for individual optimization of shuttering attributes by clinicians, for training sessions in clinical settings, or even at home, aimed at stimulating vision in the “lazy” eye. Conclusions: Multithreading offers significant benefits for data acquisition and instrument control, making it possible to implement time-efficient algorithms in inexpensive yet versatile medical instrumentation with only minimum requirements on the hardware.

AB - Background and objectives: Amblyopia, commonly known as “lazy eye,” is poor vision in an eye from prolonged neurologic suppression. It is a major public health problem, afflicting up to 3.6% of children, and will lead to lifelong visual impairment if not identified and treated in early childhood. Traditional treatment methods, such as occluding or penalizing the good eye with eye patches or blurring eye drops, do not always yield satisfactory results. Newer methods have emerged, based on liquid crystal shutter glasses that intermittently occlude the better eye, or alternately occlude the two eyes, thus stimulating vision in the “lazy” eye. As yet there is no technology that allows easy and efficient optimization of the shuttering characteristics for a given individual. The purpose of this study was to develop an inexpensive, computer-based system to perform liquid crystal shuttering in laboratory and clinical settings to help “wake up” the suppressed eye in amblyopic patients, and to help optimize the individual shuttering parameters such as wave shape, level of transparency/opacity, frequency, and duty cycle of the shuttering. Methods: We developed a liquid crystal glasses controller connected by USB cable to a PC computer. It generates the voltage waveforms going to the glasses, and has potentiometer knobs for interactive adjustments by the patient. In order to achieve good timing performance in this bidirectional system, we used multithreading programming techniques with data protection, implemented in LabWindows/CVI. Results: The hardware and software developed were assessed experimentally. We achieved an accuracy of ±1 Hz for the frequency, and ± 2% for the duty cycle of the occlusion pulses. We consider these values to be satisfactory for the purpose of optimizing the visual stimulation by means of shutter glasses. The system can be used for individual optimization of shuttering attributes by clinicians, for training sessions in clinical settings, or even at home, aimed at stimulating vision in the “lazy” eye. Conclusions: Multithreading offers significant benefits for data acquisition and instrument control, making it possible to implement time-efficient algorithms in inexpensive yet versatile medical instrumentation with only minimum requirements on the hardware.

KW - Amblyopia

KW - Liquid crystal shutter

KW - Multithreading

KW - Shutter glasses

KW - Thread-safe queues

UR - http://www.scopus.com/inward/record.url?scp=85015386020&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85015386020&partnerID=8YFLogxK

U2 - 10.1016/j.cmpb.2017.03.008

DO - 10.1016/j.cmpb.2017.03.008

M3 - Article

VL - 143

SP - 151

EP - 158

JO - Computer Methods and Programs in Biomedicine

JF - Computer Methods and Programs in Biomedicine

SN - 0169-2607

ER -