Myopia, also known as near-sightedness and short-sightedness, occurs when light focuses in front of, rather than on, the retina. As a result, distant objects appear blurry, whereas nearby objects appear normal.
Myopia occurs when the length of the eyeball grows too long or, less commonly, the lens becomes too strong. This is a type of refractive error. Cycloplegics are used during an eye examination to make the diagnosis. Tentative evidence suggests that increasing young children’s exposure to the outdoors can reduce their risk of myopia.Myopia is the most common eye problem, affecting an estimated 1.5 billion people (22% of the global population).Rates vary significantly around the world.
A myopic person can see clearly up to a certain distance (the far point of the eye), but anything beyond that distance appears blurry.If myopia is severe enough, standard reading distances can be affected. On routine examination, the vast majority of myopic eyes appear structurally identical to nonmyopic eyes.Onset is common in school-aged children, and the condition worsens between the ages of 8 and 15.
The underlying cause is thought to be a mix of genetic and environmental factors. Risk factors include doing work that involves focusing on close objects, greater time spent indoors, urbanization, and a family history of the condition. It is also associated with a higher socioeconomic status and level of education.
Current lifestyle changes are increasing eye axial length, particularly after a pandemic. As a result, the prevalence of myopia is increasing, and many practitioners consider it an epidemic. By 2050, the prevalence of high myopia will rise to 50 to 55% worldwide, up from 33% today. Some consider myopia to be the most serious threat to eye health in the twenty-first century.
Human population studies indicate that genetic factors account for 60-90% of the variance in refraction. However, the currently identified variants account for only a small proportion of myopia cases, implying the presence of a large number of unidentified low-frequency or small-effect variants that underpin the vast majority of myopia cases. Insufficient light exposure, low physical activity, close proximity to work, and increased years of education are all environmental factors that increase the risk of myopia.
People, particularly children, who engage in more physical exercise and outdoor play have lower rates of myopia, implying that the increased magnitude and complexity of visual stimuli encountered during these activities slows myopic progression.
Myopia can be induced with minus spherical lenses, and overminus in prescription lenses can cause myopia progression. Overminus during refraction can be avoided using a variety of techniques and tests, including fogging, plus-to-blur, and the duochrome test.
Myopia is typically diagnosed by an eye care professional, such as an optometrist or ophthalmologist. This is accomplished by refracting the eye using cycloplegics such as atropine, and then recording responses when accommodation is relaxed. Progressive myopia requires regular eye examinations using the same method.
Several methods have been used in an attempt to slow the progression of myopia, but studies have yielded mixed results.
1. Outdoor activity for at least 2 hours
2. Increase the distance from the device, at least 30 cm away.
3. Maintain proper reading posture; avoid reading while lying down.
4. Good lighting; avoid using devices in the dark or reading in poor lighting.
5. Take a Break: The 20-20-20 rule states that after every 20 minutes, take a 20-second break and look 20 feet away from the screen.
6. Regular eye exams for all children, especially if their parents have myopia.
Keeping children indoors, whether to promote early academic activities, because urban development decisions leave no space for children to play outside, or because people avoid sunlight because they prefer lighter skin color, causes myopia. Treatment options may include various types of lenses such as bifocals, progressives, peripheral defocus lenses, and multifocal contact lenses, orthokeratology, or myopia-controlling eye drops, depending on the individual’s needs.