The provisions of this chapter shall not be construed to apply to physicians and surgeons authorized to practice under the laws of this state, nor to any person who sells spectacles or eyeglasses on prescription from any such physician or certified optometrist; provided such person shall not attempt to measure the vision of the eye. No person granted a certificate under the terms of this chapter shall display or use the title “Doctor” or its synonym, either by way of prefix or otherwise, unless, at the same time, he appends to his name words indicating that he is an optometrist. Any person violating any provision of this section shall be subject to the penalties provided in section 20-138a.