Only if you're Superman; your gaze doesn't tranmit thermal energy.
A Heat Map isn't about thermal energy. It is a type of graph. See http://en.wikipedia.org/wiki/Heat_map. They are often used in analysis of how people read websites. You create a graph of how long a person looks at a particular part of the website, the longer they look the brighter the color (looks 'hotter' the longer they look). Then just by looking at the pattern of where they looked the longest, you can determine what interests them the most, or where to place links or images to catch their attention the fastest.
Typically this has required a research study (and consent) to perform. But it would be much easier if you could monitor a person in real-time all the time through a pair of glasses.