Kenneth J Ciuffreda, Mark Rosenfielda and Margaret A Gillard
Abstract:
Near work-induced transient myopia (NITM), a lenticular-based pseudo myopia, is commonly found in myopic teenagers and young adults. It has been speculated that its presence may be a factor in nearwork-related symptoms and in the development of permanent myopia. Thus, the differential effect of various powered near-vision lenses on NITM was investigated.
Nine young adults monocularly-viewed a near target (25cm) for 20 min through either a +4, +2, or 0 diopter (D) near lens, or a 0.5-mm pinhole, over their habitual distance prescription. Monocular distance refraction was objectively assessed immediately before and after the near task. Decreasing the accommodative stimulus reduced the blur-driven adaptive aftereffect. Only with the 0 D accommodative stimulus condition was NITM not produced.
These results suggest that the full blur-driven monocular stimulus to accommodation must be negated to prevent the occurrence of NITM. With the pinhole providing blur-free viewing conditions, a substantial proximal accommodative adaptive component was present.
My commentary (translation):
Near work can cause temporary blurring of distance vision (transient myopia), which may lead to permanent blurring of distance vision (myopia). The immediate aftereffect (transient myopia) can be completely eliminated by doing the following:
1. Using only one eye at a time (monocular viewing)
2. Using a plus lens powerful enough to completely relax accommodation (0 D accommodative stimulus).
For example, for reading at 25cm, which is 1/ 0.25m = 4 D you would need a +4 D lens over your full distance prescription. So if your distance prescription is -1.25 you would use a +2.75D lens to read at 25cm.
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