[Accommodation as the primary cause of night myopia].

Night myopia can now be measured accurately with a laser optometer. An increasing number of reports, based on work with this optometer, have supported the hypothesis that night myopia is caused by accommodation. In this study subjects with one phakic and one aphakic eye were tested with respect to the magnitude of night myopia developed in each eye. The results appear to represent the first direct experimental evidence for the hypothesis that accommodation is the primary cause of night myopia.