How can insufficient illumination cause eyestrain and physical discomfort?

Insufficient illumination, such as that provided by an inadequate lamp, can contribute to asthenopia—a condition where the eyes tire easily due to the strain of visual tasks.

When lighting is poor, the eyes must work harder to process visual information, particularly during close work like reading. This increased demand forces the muscles of accommodation to compensate continuously, leading to fatigue. This physical discomfort often manifests as:

• Pain in the eyeball
• Frontal headache
• Blurring of vision
• Smarting and watering of the eyes

These symptoms are typically exacerbated by extended periods of close work and often worsen toward the end of the day as the eyes become increasingly fatigued from the effort of maintaining focus under suboptimal conditions.1