Answer:
1: It's strange how fast I've become nearsighted.
2: We have just occupied Vienna; a far-sighted man could have foreseen the possibility some considerable time ago.
3: Airy, the astronomer, corrected his own astigmatism by means of a cylindrical lens.
4: She wanted to learn more about the vertical adjustments that need to be made in many strabismus cases.
5: He was aware of the danger of accidentally causing amblyopia of the better eye by treating children below the age of six.
Explanation: