What are her water parameters? What are the tankmates of the tetras? Also what size is her tank?
Cloudy eyes can be due to the internal parasites such as protozoa and flukes. Another possible cause is onset of cataracts. Eyes are infected and damaged by bacteria via injuries. Poor water quality will often bring this case.
Pls leave that alone. Good water conditions will definitely help rid off the cloudy eyes. Do a 10% daily water change. Medications are your last resort. If the water parameters are not good, definitely avoid the use of medications as this can have negative effects on the fish.