Q: What exactly is astigmatism?
A: Astigmatism is usually caused by an irregularly shaped cornea, the front surface of the eye. Instead of being a perfect sphere, like a ball bearing or a marble, it can become a little more like a football, being more curved in one direction than the other. This brings light into focus at more than one point on the retina at the back of the eye, resulting in blurry or distorted vision.
Q: I've heard that blue light is dangerous, like UV radiation. Do I need to protect my eyes from it and, if so, how?
A: We all know about ultraviolet (UV) sun damage, but recently, the optical community has found that high-energy visible light (HEV) or "blue light" from digital screens may cause long term damage to the eye, too. Over time, exposure can increase the risk of macular degeneration, and other problems. Similar to anti-reflective and UV-protective coatings, a new lens coating has been developed to protect our eyes by blocking out blue light rays coming from our handheld devices, computers and fluorescent bulbs.
Q: Does reading my smartphone or tablet in the dark damage my eyes?
A: Reading from a tablet or smartphone in the dark is okay for your eyes, as long as it's not for a long period of time. These devices have decent lighting and good contrast. However, they give off blue light, and long-term exposure may cause damage to the structures of the eye. As well, studies have shown that blue light at night disrupts melatonin production and interferes with healthy sleep cycles. Optometrists recommend wearing blue light blocking eyewear for extended digital device use, and limiting screen time during the last hour before bedtime.