With 300 degrees of myopia, it could be 4.3, 4.2 or 4.5, 4.6 are possible. There is no direct conversion or correspondence between myopia and naked eye vision. When the eyes are tired or overused, the naked eye vision decreases significantly and may be 4.0 or 4.1. When the eyes are well rested or well adjusted, 300 degrees of myopia, the naked eye vision may reach 4.5 or 4.6 or even higher. Myopia is generally classified as mild myopia, which is 300 degrees or less; moderate myopia 300-600 degrees; high myopia 600-900 degrees or less; and super high myopia which is 900 degrees or more.