This is the 49th most frequent Hindi word.
नजर
Sight, glance, view, or vision.
Here, 'नजर' is used to mean 'focus' or 'attention'.
उसकी नजर इस समस्या पर थी।
His focus was on this issue.
In this sentence, 'नजरें' explicitly means 'eyes'.
मुझे ऐसा लगा जैसे उसकी नजरें हर ओर घूमा रही थीं।
I felt as if his eyes were scanning everywhere.
Here, 'नजरें' refers to 'sight' or 'eyes' in a poetic sense.