Hi Fatima Functioning as nouns, I wouldn’t call them synonyms but the difference in meaning can be quite subtle. Drugs can alter your perception of reality. (Drugs can alter your understanding of reality) Drugs can alter your perspective on reality. (Drugs can alter your view of reality. In this context, although the meanings are different, the result is the same - drugs make you understand things differently. You could say, ‘Drugs alter your perspective which alters your perception’. However, they cannot always be interchanged like this and they do have other meanings. For example, ‘perceptive’ can be an adjective and you can say that ‘someone is very perceptive’, meaning that they are very good at noticing things other people don’t notice. I would really recommend getting a good learner dictionary – I wouldn’t be without mine 

people analyze situations differently - perception. (e.g)His perception of the magnitude of the problem is similar to that of mine. People use their perception of situations to make up their viewpoint and where they stand on issues - perspective. (e.g)We have a different perspective of such matters.

Your perception of something is what you see. Your perspective on something is what you think about what you see. The two can be used similarly, but not always.

Wow, thank you so much Kalia, your answer makes it clearer for me. :)

The words are different and although they can be applied to similar situations they are not synonyms. Ithink it's useful to look at the root words. Perception [noun] comes from the verb to perceive: pəˈsiːv/ verb 1. become aware or conscious of (something); come to realize or understand. "his mouth fell open as he perceived the truth" "he perceived the faintest of flushes creeping up her neck" 2. interpret or regard (someone or something) in a particular way. "if Guy does not perceive himself as disabled, nobody else should" So perception is the noun - it does not refer to the thing that you perceive but your view/opinion of it. If I perceive somebody as rude my perception refers to my view of them as a rude person - not the actual person. Perception highlight that what people understand to exist and what actually exists can be different. Perspective comes from the physical thing. When you see a square straight on you see a square, whereas when you see it from an angle you will see a rectangle. Se perspective also refers to your view of something however, it more refers to what you can see from where you are [either physically or your situation]. In contrast Perception is more about how you think and feel about something.