Answer:
He is suffering from hypermetropia.
Explanation:
There are some defects of vision.
Longsightedness of hypermetropia : It is the defect of vision in which the person is not able to see the nearby objects clearly but can see the far off objects clearly. This is due to the elongation of size of eye ball. It is cured by using convex lens of suitable focal length.
Nearsightedness or Myopia : It is the defect of vision in which a person is not able to see the far off objects clearly but can see the nearby objects clearly. It is due to the contraction in the size of eye ball. It is cured by using concave lens of suitable focal length.
So, Hideki is suffering from hypermetropia. So, he should use the convex lens of suitable focal length.