Abstract

Alternative color modes, such as light, dark, dim, and high contrast modes, in mobile apps can improve accessibility for people with vision impairments and usability for people without vision impairments across situational contexts. However, current mobile apps exhibit inconsistent color implementations for UI elements (e.g., background, text, buttons, images, and non-selectable icons), leaving users with limited accessible options. My dissertation addresses a central question in human-computer interaction and accessibility: How can mobile app designers be supported to implement alternative color modes that meet the accessibility and usability needs of people with and without vision impairments? Through an eight-study mixed-methods investigation, my work examined user needs, current implementation, and designer challenges, then created and validated evidence-based guidelines to support the creation of alternative color modes. I refer to these guidelines as the Oculux Design Guidelines, a name that combines ocular (relating to vision and the eye) and lux (the unit of illuminance), reflecting the guidelines’ focus on how light and color reach the human eye across varied display conditions. Phase 1: Understanding User Needs and Current State. Study 1 interviewed 29 people (13 with vision impairments, 16 without) and revealed that inadequate alternative color modes lead to serious consequences, including hospitalization, safety vulnerabilities requiring stranger assistance, and workplace discrimination. Study 2 analyzed 120 Android and iOS apps and found only 55% (Android) and 48% (iOS) offer dark mode, with variability in UI element implementation quality across all modes. Phase 2: Understanding Designer Challenges and Resources. Study 3 interviewed 15 designers and developers, and identified insufficient guidelines, tools, and support as the main implementation challenges, with designers reporting long, intricate creation processes. Study 4 conducted design workshops with 12 designers and confirmed the need for structured guidelines, revealing that designers rely on unverified inspiration and lack structured processes. Phase 3: Developing Guidelines. Study 5 created the Oculux Design Guidelines, informed by Studies 1–4, incorporating design processes, visual accessibility standards, tool recommendations, and user needs documentation. Phase 4: Validating Guidelines. Study 6 evaluated guideline effectiveness using a between-subjects design with 13 designers, comparing designers who created alternative color modes with guideline support to those without. Results showed that designers who used guidelines demonstrated improved understanding of design principles, greater confidence in implementing modes, comparable adherence to accessibility standards, higher mode-specific compliance for dim and dark modes, and higher perceived ease of implementation. Study 7 collected feedback from 45 designers and developers through an online survey, showing increases in motivation to implement alternative color modes and in perceived importance of accessibility following review of the guidelines. Study 8 evaluated the designs created in Study 6 through an experimental study with 24 participants (12 with vision impairments, 12 without) who rated the designs under bright and dark lighting conditions. Results showed that participants with vision impairments provided lower ratings across UI elements, usability, and accessibility than participants without vision impairments across all designs, regardless of guideline use. Preferences varied by mode and lighting condition, with guideline designs preferred for dark mode but not for high contrast mode. Across the eight studies, guidelines improved designer understanding and implementation approaches. For dim and dark modes, guideline designers produced designs with higher mode-specific compliance scores than no-guideline designers. However, creating accessible user experiences requires complementary support beyond guidelines, including user customization, adaptive systems, and iterative design informed by user feedback. The guidelines establish a foundation for improved practice while identifying areas requiring further research, particularly in image adaptation across modes, mode performance under varying lighting conditions, and personalization approaches that accommodate diverse user needs.

Publication Date

4-2026

Document Type

Dissertation

Student Type

Graduate

Degree Name

Computing and Information Sciences (Ph.D.)

Department, Program, or Center

Computing and Information Sciences Ph.D, Department of

College

Golisano College of Computing and Information Sciences

Advisor

Garreth Tigwell

Advisor/Committee Member

Kristen Shinohara

Advisor/Committee Member

Roshan Peiris

Campus

RIT – Main Campus

Download

Share

COinS