Myopia: For example, the far point of myopia is located 26.5 cm in front of the eye, the corrective glasses are placed 15 mm in front of the cornea, the focal length is F=0.265-0.015=0.25m, the refractive power F=-4.00D. Hyperopia: Invisible hyperopia: caused by physiological contraction of the ciliary muscle, which can come out after ciliary muscle paralysis. Dominant hyperopia: including able hyperopia and absolute hyperopia. Able hyperopia (energetic hyperopia) is regulated compensated hyperopia, and absolute hyperopia is not compensated by regulation. Total hyperopia: 6.50 Dominant hyperopia: +5.50D Invisible hyperopia: +1.0D Energetic hyperopia: +5.50-(+2.50)=+3.0D Absolute hyperopia: +2.50D