Understanding Nearsightedness and Farsightedness: Genetics vs. Screen Time

Is it possible to develop nearsightedness (myopia) or farsightedness (hyperopia) from prolonged use of a computer screen? The answer to this question often revolves around genetic factors and not necessarily the duration of close visual tasks. This article delves deeper into these conditions and clarifies how they are influenced by genetics and other factors.

The Cause of Nearsightedness and Farsightedness

Genetic Predestination

Surprisingly, myopia or hyperopia usually results from genetic factors rather than the frequency or duration of close visual tasks. Historically, nearsighted individuals often appear to spend more time focused on close objects because they struggle to see distant objects clearly. However, this is a symptom of the presence of these conditions rather than a cause.

Myopic Lifestyle and Genetic Predisposition

Ben Wilkinson, FRCSC, in 2020, suggests that myopia is a largely genetic condition. It develops during growth and stabilizes around the age of 17 to 21. There is increasing evidence that myopia is more common today, possibly due to genetic traits associated with rapid growth. A notable historical example is the Japanese population, where a significant dietary and physical change led to an increase in myopia rates.

Causes Beyond Genetic Factors

While genetics play a critical role, other factors such as changes in diet and lifestyle, can also contribute to the increasing prevalence of myopia. Countries with more Western dietary habits and growth patterns are showing higher rates of nearsightedness. The debate around the reasons for this increase remains active, but it is widely acknowledged that genetic predisposition is a crucial factor.

Can Prolonged Computer Use Cause Nearsightedness?

Pseudomyopia vs. True Myopia

It is possible to develop a condition known as pseudomyopia, which can result from prolonged close focusing, but this is not true myopia. Pseudomyopia involves the cramping of the focusing muscles, preventing them from relaxing to allow clear distance vision. This condition can be diagnosed by measuring the patient after the dilating drops have had their effect of temporarily paralyzing the focusing muscles.

Pseudomyopia usually resolves after sleep, which can relax the focusing muscles. This temporary condition can be mistaken for true myopia, leading some individuals to seek treatment for myopia that does not actually address the root cause. It is important to differentiate between true and pseudomyopia to ensure appropriate management.

Treating and Managing Nearsightedness and Farsightedness

Correcting Refractive Errors

The refractive errors caused by myopia and hyperopia can be corrected using glasses, contact lenses, or orthokeratology. Orthokeratology involves wearing contact lenses at night to reshape the cornea, providing correction without lenses during the day. Refractive surgery, such as LASIK, is another option to alter the curvature of the cornea.

Managing Myopia with Assistantive Devices

Whether to wear glasses or contacts all the time is a personal choice. Glasses correct the optics to normal, allowing the eyes to behave as they would without glasses. This means that with the eyes relaxed, they focus on the far distance (infinity), but when an object comes near, the muscles are used to keep the object in focus. This is normal.

For those who wear glasses, the prescription can help manage myopia without making it better or worse. In the case of moderate to high myopia, there is a risk of complications, which increase with stronger prescriptions. These complications are believed to be due to a stress between the size of the sclera (outer tough layer of the eye) and the retina (light-sensitive film in the eye), which are derived from different kinds of tissue in the embryo.

Conclusion

In conclusion, the development of nearsightedness or farsightedness is predominantly influenced by genetic factors rather than the amount of time spent on close visual tasks or prolonged computer screen use. While it is possible to develop pseudomyopia, this condition is not a form of true myopia and usually resolves with rest. Understanding these distinctions can help in managing myopia and hyperopia effectively and in making informed decisions about treatment options.