More Serious Than Blue Light? New Eye Strain in the Smartphone Era

Every day, as I measure the eyesight of many people, I notice a common characteristic of eye strain among those under 40.

It is a problem with how we use our eyes that is unique to the smartphone era and cannot be explained by blue light alone.

1. Eye strain in the smartphone era is not a "blue light problem"

From elementary school students to adults, smartphones have become the center of our lives.
At the same time, there has been an increase in consultations regarding "vague eye fatigue" and "feeling heavy-headed by the evening."

However, what I feel in the field is that
eye strain caused by the "movement of the eyes themselves" is increasing more than blue light
itself.

2. Smartphones are a "30cm world"—an environment where our gaze is too converged

Because smartphones are held in the hand, the distance naturally becomes close.
It is around 30cm for adults, and sometimes even closer for children.

When human eyes look at something nearby, they adjust their focus while simultaneously
the gaze converges inward (convergence)
occurs.

This is a normal reaction, but the problem starts here.

3. "Convergence habits" vary greatly from person to person

• People who barely converge

• People who converge more strongly than necessary

For the latter type, at smartphone distance, the gaze converges too much and cannot return, which leads to severe fatigue.

What is important here is

the fact that while you can converge, it is difficult to diverge

the fact.

In other words, people who tend to over-converge are
in a state of being forced to continue a difficult movement
.

There is no way they wouldn't get tired from this.

4. The solution is simple—just "weaken the focus adjustment"

If the cause is "over-convergence,"
adjusting the prescription so that less focus adjustment is required
makes it surprisingly comfortable.

The difficult part is the "discovery," as it is easy to overlook if you are not used to it.

5. The "missed point" I noticed while observing young staff members' measurements

Recently, while training young staff, I noticed a significant difference in their discovery rates.

• I am teaching them the procedures

• It cannot be explained by the difference in experience alone

• Yet, they are not finding the "over-convergence type" as well as I am

When I reviewed all the measurement procedures, I found that
the step of "intentionally stimulating focus adjustment" was missing
.

When I added this point to the training,
the staff's discovery rate improved significantly.

6. 20-30% of smartphone fatigue might be this type

Although I haven't taken statistics,
my practical experience in the field suggests that 20-30% of people under 40 may have this problem.

Once discovered, the solution is not difficult.
I shared this insight in the hope that it will provide some relief to those suffering from eye strain in the smartphone era.

7. Summary: Smartphone fatigue is not "your fault"

The true nature of smartphone fatigue is
the incompatibility between your eye habits and the smartphone environment.

Rather than blue light reduction,
identifying excessive eye convergence
is what I feel is the essential approach to the new eye strain of the smartphone era.