Active Focus
Active focus is the principle that vision improves in the long term when eyes are given a small blur challenge that they successfully resolve. Active focus is a habit, not an exercise routine.
Resolvable blur is the stimulus that decreases the axial length of the eye, reversing myopia. Conversely, excessive sharpness is the stimulus that increases the axial length of the eye, leading to myopia. These axial length changes take place slowly, over years. It took years for myopes to become as nearsighted as they are today, so it takes years to completely reverse it. In order to achieve results, active focus must be a habit, something that myopes are always doing without thinking much about it.
Active focus is a balancing act. Too much blur, and the eyes will not be able to resolve the blur challenge. When the challenge is unresolved, there is no long-term vision improvement. If the object in focus is too sharp, then myopic eyes are not getting the necessary stimulus to improve. Wearing a full correction will result in a blur horizon of infinity, meaning that the eyes will never get the necessary blur, even if looking as far away as possible. It's best to rarely wear the full prescription, and instead wear differential and normalized lenses depending on the situation.
Practitioners of active focus may experience fast progress at first, and then slow progress. Eye care professionals may over-prescribe the corrective power of lenses, so dropping the over-prescribed diopters may feel like instant "progress". Pseudomyopia can be treated quickly, so it may be another source of fast initial progress. Beyond over-prescription and pseudomyopia, the speed of the journey to 20/20 is estimated by Jake Steiner to be roughly 0.25 diopters every 3 months.
Just how active is active focus?
With active focus, the myopia sufferer must actively adjust the distance to objects and what glasses they are wearing, to habitually create the optimal challenge. It's really that simple! The eyes take care of the rest. Focus is an automatic process that the eyes and the visual cortex do on their own.
What am I doing wrong?
My vision doesn't clear up when I look at blurry objects!
The blur challenge is too strong. Look at objects that are closer to you, or wear stronger eyeglasses. The blur challenge should be easy to overcome. You will know that your eyes have overcome the blur challenge when an object that at first appears blurry becomes sharp.
The thing I'm looking at clears up instantly. This is great!
While it's great that you are seeing that object clearly, the blur challenge is too weak. Look at objects that are farther away, or wear weaker eyeglasses.
My vision is only clear after I blink!
Extra forced blinking is not part of active focus. If you find that blinking helps, you may have dry eye syndrome. Blinking is depositing a fresh tear film on the surface of the eye, creating a perfectly smooth, polished surface that improves vision. You should take steps to resolve your dry eye syndrome, so that your dry eyes do not continue to cause problems when practicing active focus.
My vision is only clear in sunlight!
Sunlight causes your pupils to constrict, creating a pinhole effect that temporarily improves vision. There is nothing bad about the sunlight-induced pinhole effect, and being in the sunlight is encouraged. In order to practice active focus indoors, wear a slightly stronger prescription.
I'm not improving!
This is a slow process. Keep at it! Make certain that you are getting the necessary blur challenge as often as possible.