The link provided above only states WHICH medical expenses you can claim, it does not mean you are eligible. A lot of people automatically assume they can claim any and all expenses. Well, to be honest, you can claim anything to the moon and back, but if you're audited, you will owe it back... With interest!
Having said that... How to know if you're eligible? You either have VERY high medical expenses OR very low income.
Here's the specific criteria:
Under the first calculated amount in the medical expense tax credit formula, an individual may claim the amount by which the eligible medical expenses in respect of the above listed people exceeds the lesser of the following two amounts:
a fixed amount ($2,152 for 2013) indexed annually in accordance with subsection 117.1(1): and
3% of the individual’s net income for the year.
Basically, if it exceeds the above amount or if the amount of expenses exceeds 3% of your annual income.
For further details, follow this link:
http://www.cra-arc.gc.ca/tx/tchncl/ncmtx/fls/s1/f1/s1-f1-c1-eng.html