Myopia (Nearsightedness):
What is Myopia?
Myopia is the medical term for nearsightedness. What this means is that you can see objects clearly up close, but objects further away are less clear. You might have difficulty seeing road signs, or squint often. It has quickly become one of the most common vision problems in the United States. It is estimated that over 40% of the US population is nearsighted. This is in stark contrast to 50 years ago, where only about 25% of Americans were nearsighted. Severe myopia (degenerative myopia) has been linked to increase risk of cataracts, glaucoma, and retinal detachment.
How is Myopia caused?
The exact cause of myopia has not been confirmed, but it has been linked to a variety of factors such as:
1. “Near” activities, such as reading or using hand-held electronics.
2. Lack of sun exposure
3. Genetic predisposition
Researchers have linked increased emphasis on studies and the prevalence of myopia. Studying takes up a large portion of children and young adults’ time, and includes many “near” activities such as reading and writing. For example, in China, it’s reported that almost 90% of teenagers and young adults are nearsighted, compared to only 20% 60 years ago. This also goes hand-in-hand with lack of sun exposure. With more and more time spent studying indoors, less time is allocated to outdoor activities. Researchers have known that spending time outdoors lowers the risk of childhood myopia. However, the exact reason for this hasn’t been found. Recent research did find that kids could maintain healthy vision by spending atleast three hours per day outdoors. The study suggested that this exposure to sunlight could actually prevent myopia irrespective of the amount of “near” activities performed, or genetic predisposition to myopia.
How to Prevent Myopia:
1. Limit the amount of “near” activities performed, especially in children. Allow eyes to rest often by taking frequent breaks and focusing on objects further away.
2. Spend time outdoors, in sunlight.
3. Corrective glasses, lenses, or surgery.
One of the most difficult aspects of myopia is that, commonly, it worsens year after year. This means that glasses with thicker and heavier lenses or higher prescription contact lenses are needed each year. If action isn’t taken to slow or prevent the progression of myopia, it can lead to dependency on corrective lenses for the remainder of that person’s life. Myopia is largely non-reversible without surgery.
Another important aspect regarding myopia is that over-correction (too high of a prescription) on corrective lenses can lead to rapid deterioration of vision. It is important that the prescription of the corrective lenses (glasses or contacts) NOT exceed the required correction for your vision. To illustrate more clearly: a patient may require a -1.25 correction in both eyes, but can see fine (only slightly less clear) with just a -1.00. It is recommended to opt for the lower, -1.00, prescription so as to not over-correct and cause rapid progression of myopia. Unfortunately, not all optometrists do this, and the practice of over-correction has led to irreversible vision damage for many people. In this regard, Dr. Truong ALWAYS tries to find the LOWEST possible prescription for her myopia patients that provides a good balance of vision correction and comfort, without risking any over-correction. She has found that this practice can significantly slow the progression of myopia in her patients (save their vision), prevent thicker and heavier glasses year after year (no ugly or uncomfortable glasses), and prevent the need to constantly purchase new, higher prescription lenses (save her patients money).
Thanks for reading, and we hope you learned a lot about myopia and how to prevent it!