Document Type


Date of Degree

Spring 2017

Access Restrictions


Degree Name

MS (Master of Science)

Degree In

Biomedical Engineering

First Advisor

Garvin, Mona K.

Second Advisor

Kardon, Randy H.

First Committee Member

Garvin, Mona K.

Second Committee Member

Kardon, Randy H.

Third Committee Member

Johnson, Chris A.

Fourth Committee Member

Mackey, Michael A.

Fifth Committee Member

Wahls, Terry L.


Sensory deficits represent a major global public health problem. According to the World Health Organization, vision impairment affects an estimated 300 million people worldwide, and hearing impairment affects an estimated 360 million people worldwide. Consistent clinical evaluations for all individuals with sensory deficits cannot be practically realized due to the rising costs of healthcare, capital and labor limitations, and inaccessibility to healthcare due to a multitude of factors including proximity. The high prevalence of visual and hearing deficits can be lessened through consistent, comprehensive, at-home testing which can allow a larger amount of the affected and at-risk populations to be screened for abnormal function earlier and prior to permanent loss, and provide a wealth of patient-specific data that can be used to understand the time-scale of diseases and monitor the effectiveness of clinical interventions in unprecedented detail. While health-oriented smartphone applications exhibit a strong presence on the app stores, these applications are seldom vetted by expert scientists, engineers, and clinicians, and there are considerable opportunities for methodological improvements. The present work discusses the creation, calibration, and proof-of-concept, preliminary validation of a suite of psychophysical tests implemented as smartphone applications that can be utilized to rapidly and objectively quantify several functional sensory behaviors including flicker sensitivity, contrast sensitivity, visual acuity, and hearing-in-noise. Rigorous steps were undertaken to perform the necessary calibrations (a feat not routinely achieved by the creators of existing medical smartphone applications), and ensure the technical validity of the varying stimuli presented. Preliminary tests in the clinic have documented the potential of these tests to objectively provide numerous quantifications of, but not limited to, individual visual and hearing function, and variation between normal and abnormal subjects and function. The foundation laid by this work allows novel psychophysical tests to rapidly be implemented, vetted, and added to this battery of publicly and universally accessible medical smartphone applications.

Public Abstract

Vision and hearing impairments affect hundreds of millions of people worldwide. The current era of smartphones has the potential to provide universal, at-home self-testing of sensory function, namely vision and hearing, through well-engineered, vetted smartphone applications. While existing medical smartphone applications lack the necessary clinical and technical validation to be accepted and adopted by networks of clinicians and researchers, the presented suite of smartphone applications has been rigorously designed within the confines of smartphone technology and hardware, and tested through a series of preliminary, proof-of-concept experiments. Results obtained to-date demonstrate the potential of the implemented tests to quantify sensory behavior of individuals as well as functional differences between normative subjects and patients with impaired visual function.


Contrast Sensitivity, Flicker Sensitivity, Medical Smartphone Application, Vanishing Optotypes, Visual Acuity


xviii, 152 pages


Includes bibliographical references (pages 99-101).


Copyright © 2017 Kasra Zarei