Ever wondered how Optometrists check a child's vision before they are able to read an eye chart or answer the infamous "what's better 1 or 2"? Answer: There is an instrument called a retinoscope that your Optometrist can use to assess the way light bounces off the back your child's eye. By using lenses and a retinoscope, an educated guess as to the prescription can be formed. This is not as accurate as a full refraction (what's better 1 or 2) but using this less interactive technique, Optometrists assess for may types of vision problems. Every child should have an eye exam before their third birthday. dr.j