Yes, squinting often can indeed improve the vision. The purpose of squinting is to moisture the cornea. The movement of squinting may keep the invisible tears excreted from the tear gland keep balance between the conjunctiva and the cornea. At the same time, this movement can get rid of the dirty things coming into the eyes, such as the dust, sand and so on. If you work in front the computers, you should keep squinting 30 or 40 times a minute in order to let your eyes moisture.
Yes, actually squinting can improve your vision. Squinting slightly changes the eye's shape, and hence its optical properties. It also forces the light through the center of the lens, which has a more precise focus than the edges. It is a quick method to assess best corrected vision. By looking through a pinhole, the refractive errors of the peripheral cornea and crystalline lens of the eye are significantly reduced or eliminated, and acuity simulates that with proper glasses in place. Squinting is not a long-term solution for improved vision. It markedly constricts the visual field and reduces total illumination.