Eye strain

Symptoms and signs

Symptoms of eye strain are divided into internal symptom factors (ISF), such as ache behind the eye from accommodative and vergence stress, and external symptom factors (ESF), like burning and irritation linked to the ocular surface. Common symptoms include blurred vision, headache, sore or burning eyes, dry or watery eyes, eye discomfort, difficulty concentrating, and sensitivity to bright lights. These can be grouped by mechanism: ocular surface issues, accommodative difficulty, vergence misalignment, and extra-ocular muscle discomfort.

Diagnosis

Diagnosis begins with a symptom history covering screen time, reading habits, lighting, sleep, and symptom duration. An eye exam checks visual acuity, how the eyes focus and move together, and looks for dryness or inflammation. A refraction test determines if new or updated glasses or contact lenses are needed, as uncorrected refractive error is a top cause. The doctor also rules out other conditions such as dry eye disease, glaucoma, convergence insufficiency, or underlying medical issues.

Therapy

Treatment involves environmental modifications and visual aids. Taking periodic breaks by closing the eyes and blinking frequently helps relieve ocular muscle strain.

The 20–20–20 rule—looking at something 20 feet away for 20 seconds every 20 minutes—is often recommended for digital eye strain. Research supports structured break schedules as effective, with short, frequent breaks reducing visual fatigue more than longer, less frequent ones. Adjusting screen brightness and contrast, optimizing ambient lighting, and changing text color can further improve comfort.