Q: My previous eye doctor told me I have “stigma!” Am I going to go blind?
A: Stigma is actually referring to a type of refractive error known properly as astigmatism, and no, you will not go blind from having astigmatism; it is not a disease. In fact, this condition is relatively common. There are three types of refractive errors: myopia, hyperopia and astigmatism. The former two are also known to as nearsighted (cannot see far away) and farsighted (cannot see up close). Astigmatism is simply the third category; it can affect both the near and far vision. Much like nearsightedness or farsightedness, astigmatism is corrected using glasses or contacts. Technically speaking an eye with astigmatism requires two different prescriptions to correct vision in one eye, due to the more oval shape of the cornea. For contact lens wearers, this will require a more specialized contact lens and a more in-depth fitting procedure.
Q: What is blue light and why is it dangerous?
A: Blue light is part of visible light and has a wavelength close to UV rays on the light spectrum. It is naturally produced by the sun, given off by fluorescent light bulbs, and emitted by LED screens on computer monitors, tablets, and smartphones. The eye's natural filters do not block blue light and chronic exposure may increase your risk for age-related macular degeneration. Evidence also shows that blue light exposure can lead to sleep problems.
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.