You can see which expenses are eligible here: http://www.cra-arc.gc.ca/tx/ndvdls/tpcs/ncm-tx/rtrn/cmpltng/ddctns/lns300-350/330/llwxpns-eng.html#d...
This would be filled out as a medical expense. Under the profile section, there is a radio button that you can select to indicate that you have medical expenses, and you will be prompted to fill that information in the deductions portion of the interview.
It appears that you are using the free product, which does not support entering medical expenses. In order to do so, you will have to upgrade to the Standard version of Turbotax (it will prompt you to do so before entering your expenses)