If a person drives a motor vehicle on a road while his eyesight is such (whether through a defect which cannot be or one which is not for the time being sufficiently corrected) that he cannot comply with any requirement as to eyesight prescribed under this Part of this Act for the purposes of tests of competence to drive, he shall be guilty of an offence.
A constable having reason to suspect that a person driving a motor vehicle may be guilty of an offence under subsection (1) above may require him to submit to a test for the purpose of ascertaining whether, using no other means of correction than he used at the time of driving, he can comply with the said requirement as to eyesight; and if that person refuses to submit to the test he shall be guilty of an offence.