Eye Strain
|
Feeling pain or pressure inside your eyes after staring at the computer?
Escondido Eyecare offers solutions for eye strain: -Progressive glasses -Computer glasses -Office Lens/Near variable focus glasses -Anti fatigue glasses -Blue blocking glasses |
|
Performing near tasks (such as staring at a computer monitor or a cell phone, or even reading a book) too close, or for too long causes eye strain.
Assuming you have perfect vision (or you are wearing glasses or contact lenses with a very recent prescription), the Ciliary Muscle has to change the shape of the Lens to make you focus near.
At 20 feet, the muscle is doing zero work. At 3 feet, it is doing approximately 1 unit of work (known as "diopter").
After that, every time you half the distance, you double the amount of work the muscle has to do to focus.
Therefore, if you hold something at 2 inches from your eyes, the muscle has to work 20 diopters versus only 3 diopters if you hold it at 13 inches.
Assuming you have perfect vision (or you are wearing glasses or contact lenses with a very recent prescription), the Ciliary Muscle has to change the shape of the Lens to make you focus near.
At 20 feet, the muscle is doing zero work. At 3 feet, it is doing approximately 1 unit of work (known as "diopter").
After that, every time you half the distance, you double the amount of work the muscle has to do to focus.
Therefore, if you hold something at 2 inches from your eyes, the muscle has to work 20 diopters versus only 3 diopters if you hold it at 13 inches.
|
|
Overworking the muscle will lead to pain starting behind the color of the eye in the eyebrow area.
The pain will keep spreading to the forehead causing headaches.
Harmon's Rule
Position your computer monitor between 24 inches (61 cm) from your eyes.
The distance between your shoulder and your knuckles is a good approximation of this length.
For all other near activities (such as cell phone, reading, playing with hand-held video games, etc.), 16 inches (40 cm) is considered appropriate.
The distance between your elbow and your knuckles is a good approximation of this length.
20/20 Rule
Even if you are not looking at something too close, you can still overwork the muscle by making it work for too long. For every 20 minutes spent looking at a near object, stare at 20 feet for 20 seconds.
Note: Even if you follow these recommendations, your vision may still worsen, due to other factors involved, such as heredity for example.
The pain will keep spreading to the forehead causing headaches.
Harmon's Rule
Position your computer monitor between 24 inches (61 cm) from your eyes.
The distance between your shoulder and your knuckles is a good approximation of this length.
For all other near activities (such as cell phone, reading, playing with hand-held video games, etc.), 16 inches (40 cm) is considered appropriate.
The distance between your elbow and your knuckles is a good approximation of this length.
20/20 Rule
Even if you are not looking at something too close, you can still overwork the muscle by making it work for too long. For every 20 minutes spent looking at a near object, stare at 20 feet for 20 seconds.
Note: Even if you follow these recommendations, your vision may still worsen, due to other factors involved, such as heredity for example.
