Water has a refractive index of 1.33 relative to air (1.00). It is logical to assume that her pupil is designed for water, and refracts the rays at the water / eye transition exactly so as to focus on the retina. Also, the cornea of the eye must have a higher refractive index than water (for the same purposes). If, instead of water, there is air outside, then the difference in the coefficients will increase even more – refraction will increase – and the picture will be focused before reaching the retina. Those. myopia.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.