Written by Dr Uma Malliah How many times have we been told that reading in dim light damages our eyesight and asked not to stretch reading hours with a bedside lamp? Or junk reading on a tablet device at night? This is the most common misconception that’s floating around on the internet. While reading in low light conditions can cause temporary eye strain and discomfort, it does not lead to permanent damage or deterioration of vision. There is no scientific evidence or study that has proven damage. What happens when you read in low light? In low light conditions, the pupils dilate to allow more light to enter the eye. This dilation can cause the eyes to work harder to focus, potentially leading to eye fatigue. Additionally, the contrast between text and background is reduced in dim light, making it more challenging for the eyes to distinguish letters and words. The ciliary muscles, responsible for changing the shape of the eye's lens to focus on near objects, may also strain more in low light conditions. This increased effort can result in temporary symptoms such as headaches, eye discomfort and red eyes. It can lead to drying of the eyes because you blink less often. However, these effects are transient. Once the eyes are given a chance to rest or are exposed to better lighting conditions, they typically recover without any long-term consequences. The human eye is remarkably adaptable and can adjust to various lighting conditions without sustaining damage. Is reading on devices safer as they have built-in lighting? This is again a misconception. Remember the letters on any blue-light emitting device, be it a phone or tablet, are not as sharp as that of a book and have a problem of contrast levels. Looking at a bright screen in low light can also cause eye strain because the eyes have to quickly adjust between the brightness of the screen and the dark surrounds. How do you know you have eye strain? 1) Itching and burning sensation in the eyes. 2) You may experience temporary blurriness. 3) If you’ve been reading something on a digital screen for a long time, you may complain of headaches. 4) Your eyes may feel dry or begin to water. 5) You may find it difficult to focus on nearby objects. 6) You may become more sensitive to light, both natural and artificial. 7) Sometimes there could be neck and shoulder pain as you strain to fix your gaze on the screen. How to reduce eye strain? To reduce eye strain when reading, it's advisable to: 1. Ensure adequate lighting. 2. Take regular breaks (follow the 20-20-20 rule: every 20 minutes, look at something 20 feet away for 20 seconds). 3. Maintain proper reading distance. 4. Use appropriate corrective lenses if needed. 5. Lubricate your eyes if working for long. (Dr Malliah is Senior Consultant, Ophthalmology, Indraprastha Apollo Hospitals, New Delhi)
