Can you see well enough to read a book, yet struggle to see far-away objects? If so, you may have myopia—also known as nearsightedness.
Myopia is a very common condition. In fact, about 23 percent of the total global population is myopic, [1] making myopia the most common refractive error of the eye. Furthermore, myopia is on the rise. Between 2000 to 2050, researchers predict that nearsightedness will soar from 1.4 billion cases worldwide to 4.8 billion cases. [2]
From an overall health perspective, myopia is not usually cause for alarm since there are many treatment options to help improve vision in nearsighted individuals. However, cases that progress rapidly or are more severe require special oversight and care, since some forms of myopia can lead to extremely poor visual acuity or, in some cases, legal blindness. Also, in very rare cases, myopia can be degenerative or malignant, requiring surgical intervention.
What Causes Myopia?
If you have myopia, your kids are at higher risk of developing it too. In most cases, the condition first appears during childhood, progresses over time, and then starts to stabilize in early adulthood. But why do we get myopia in the first place? In short, it’s because our eyes are too long.
Vision seems simple and automatic, but it’s actually a complex process involving reflection and precise focusing of light rays. First, light reflects off of an object and enters your eyes through your corneas. Next, the light bends as it passes through the lens of your eye. At this stage, in order to see perfectly, the light rays must bend in such a way that they focus at a single point on your retina, located at the back of your eye. When this occurs, vision is usually crisp and clear.
However, most people who have myopia have longer eyes. As a result, the light rays meet before they reach the retina. A cornea that is too curved in shape is another possible cause of myopia. In either case, the resulting light-scatter causes visual distortion and blur when viewing objects at a distance.
Unfortunately, myopia doesn’t always stay the same—it can get worse, especially in children. Modern lifestyle plays a meaningful role in myopia progression. Researchers believe that long hours spent in the classroom and less time spent outdoors are risk factors for myopia. [3] They also project that myopia will continue to increase as a result of modern lifestyle changes including more near-work activities, such as using computers and portable electronic devices, including smartphones. [4]
How Myopia Is Diagnosed
If you have to squint to see things far away, or if you sometimes experience eyestrain or headaches, you may have myopia. Some people wait years before reporting these symptoms to an eye doctor because they have no idea how much more clearly they could see if their myopia was corrected. This is one of many reasons why regular comprehensive eye examinations are so important.
When you visit your eye doctor for a comprehensive eye examination, several tests will be performed, including retinoscopy, a visual acuity test, and refraction. Retinoscopy gives your eye doctor an approximate idea of how mild or severe your myopia is. This is determined by shining a light in your eye. In some practices, a computerized auto-refefractor is used instead.
Next, your doctor will check your visual acuity by asking you to read the letters on an eye chart.
Finally, to determine the best prescription for your eyes, the doctor will use trial lenses or an instrument called a phoropter to show you what your vision could be with different lenses. You will be asked to identify which option looks best.
Treatments for Myopia
Because refractive errors impact how well you see, they can significantly interfere with your daily life and pose safety hazards if left untreated. The good news is, there are several effective ways to correct myopia, including glasses, contact lenses and surgery.
Spectacle options are so diverse, there is truly a design to suit almost any style. But, if wearing glasses doesn’t appeal to you, contact lenses are a wonderful alternative. Contact lens fitting usually involves an additional examination of your ocular surface to determine the perfect lens for your unique eyes.
Contact lenses also come in many different replacement schedules. Some are single-use—meaning you throw them away after wearing them once, and put on a fresh pair every morning. Other types of contact lenses can be re-worn, but need to be properly disinfected regularly as directed by your doctor.
A special type of contact lens treatment, called orthokeratology, involves wearing contacts overnight, while you sleep. Then, during the day, you can see well without glasses or contact lenses. This type of treatment is sometimes used in children as a way of slowing the progression of myopia so that vision doesn’t deteriorate too much or too quickly. Myopia control is a particularly important concern in children and many new myopia control options are currently being investigated.
Finally, if you are looking for complete freedom from glasses and contact lenses, refractive surgery, such as LASIK or PRK may be right for you. These outpatient procedures have been proven to be safe and effective for millions of people who struggle with myopia.
[1] Holden BA, Fricke TR, Wilson DA, Jong M, Naidoo KS, Sankaridurg P, Wong TY, Naduvilath TJ, Resnikoff S. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology. 2016 May;123(5):1036-42.
[2] Holden BA, Fricke TR, Wilson DA, Jong M, Naidoo KS, Sankaridurg P, Wong TY, Naduvilath TJ, Resnikoff S. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology. 2016 May;123(5):1036-42.
[3] Holden BA, Fricke TR, Wilson DA, Jong M, Naidoo KS, Sankaridurg P, Wong TY, Naduvilath TJ, Resnikoff S. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology. 2016 May;123(5):1036-42.
[4] Holden BA, Fricke TR, Wilson DA, Jong M, Naidoo KS, Sankaridurg P, Wong TY, Naduvilath TJ, Resnikoff S. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology. 2016 May;123(5):1036-42.