Abstract: Digital eye strain is a cross-system condition that arises from interactions between visual physiology and digital displays. As the use of screens has grown in work, education, and everyday life, researchers have sought to describe this condition through symptom questionnaires (CVS‑Q, CVSS17, DESQ), measurements of the ocular surface and blinking, tests of accommodation and vergence, and, in related visual fatigue studies, neurophysiological methods such as electromyography and electroencephalography (EEG). Nevertheless, these methods have usually examined individual mechanisms separately. Interventions—ranging from lubricating the ocular surface and filtering blue light to ergonomic changes, task‑specific refractive correction, and scheduled micro‑breaks—have seldom been guided by a unified mechanistic framework. This review compiles evidence from 128 studies to identify six mechanistic domains relevant for clinical assessment. These include ocular surface and blink dynamics, accommodation and vergence, musculoskeletal load, device-related optical stress, cognitive load, and neural markers. A systematic search of PubMed/MEDLINE, Embase, Scopus, and Web of Science was carried out through September 30th, 2025, in accordance with PRISMA guidelines. Eligible studies included randomized trials, controlled interventions, cohort studies, and laboratory experiments, with methodological quality evaluated using the Mixed Methods Appraisal Tool. Results across pediatric, adolescent, working‑age, and presbyopic groups indicate that cognitive load reduces blinking and destabilizes accommodation. Binocular incongruence links visual effort with trapezius activation, and EEG markers can precede subjective fatigue. Interventions aligned with these mechanisms—such as ocular surface care, accommodative/vergence correction, ergonomic optimization, and micro‑break scheduling—are supported across all domains. The review proposes a mechanism‑based triage model to assist clinicians in prioritizing interventions based on the patient’s exposure profile, breaking neuro‑ocular feedback loops, and preserving functional performance in individuals exposed to screens. The framework provides an actionable, mechanism‑first triage checklist for optometric practice. Plain Language Summary: Digital eye strain is the collection of eye, neck, and mental fatigue symptoms that many people experience when using computers, smartphones, or tablets for long periods. These symptoms include dryness, burning, blurred vision, headaches, and shoulder or neck discomfort. Although common, digital eye strain does not come from a single cause. Instead, it results from several interacting factors involving the eyes, brain, posture, and design of digital screens. This review synthesizes 128 studies to explain the development of digital eye strain and how it can be more effectively managed. Reduced blink frequency and completeness due to screen use destabilize the tear film, leading to dryness. Near focus over an extended period can cause strain on accommodation and vergence systems, particularly among children, teenagers, and those with untreated vision impairments. Poor posture, short viewing distances, and small screens increase the activity of neck and shoulder muscles. Performing multiple tasks simultaneously or engaging in demanding digital work significantly increases mental stress by requiring greater mental effort and resulting in a lower blink rate. Studies using EEG demonstrate brain fatigue preceding the onset of symptoms. The review proposes a practical, mechanism-based approach for clinicians: identify which system is most stressed (ocular surface, focusing, posture, device factors, or cognitive load) and match treatment accordingly. This may include lubricating drops, blink training, vision therapy, ergonomic adjustments, scheduled movement breaks, or screen-based lighting changes. Understanding these mechanisms can help people use digital devices more comfortably and protect long‑term visual performance. Keywords: digital eye strain, computer vision syndrome, ocular surface, electroencephalography, ergonomics, musculoskeletal disorder
Prithwis Manna (Sun,) studied this question.