Photosensitive epilepsy (PSE) is a neurological condition in which seizures are triggered by certain visual stimuli, such as flashes, strobes, or bright patterns. People who have been diagnosed with photosensitive epilepsy often struggle to use digital technology safely, as strobing lights can appear on screens without warning in ways that are difficult to anticipate and avoid. Given the severe medical complications and adverse outcomes associated with seizures, it is fundamental that digital platforms have systems to detect and mitigate seizure-inducing content before it reaches users with photosensitivity. However, detecting seizure-inducing content on digital platforms can be complicated due to variations between technology modalities, unpredictable sources of seizure-inducing flicker, and differences in sensitivity levels among people with PSE. This dissertation examines design considerations for minimizing photosensitive risk in digital spaces that are social, interactive, and even immersive in nature. This work establishes a theoretical foundation for incorporating photosensitive epilepsy into the broader research area of digital accessibility, building on prior work in human-computer interaction research. Through software prototypes and interviews with people with PSE, this work explores the benefits and limitations of creator-, consumer-, and platform-driven systems for detecting and mitigating photosensitive risk across digital platforms. Finally, this work encompasses several empirical studies that contribute to broader knowledge about the prevalence and presentation of seizure-inducing content on digital platforms. am forever grateful for the encouragement and support shown by Bruce Draper and Ross Beveridge in advising my undergraduate thesis efforts on the topic of photosensitive accessibility. I am also grateful to Janne Lindqvist for his advice and guidance while at the DIMACS REU at Rutgers University, which was a formative experience in learning what research can be. I have been lucky to find talented and kind collaborators and peers at Northeastern University and beyond over the past six years: thank you to