Sayyiduna Ali (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) commanded us to carefully examine the ears and eyes (of the sacrificial animal).
Because it is preferable to slaughter an animal with sound eyes and ears, this does not mean that it is forbidden to sacrifice an animal with (minor) defects in the eyes or ears.
Hadith Referenceصحيح ابن خزيمه / جماع أبواب ذكر أفعال اختلف الناس فى إباحته للمحرم، نصت سنة النبى صلى الله عليه وسلم أو دلت على إباحتها / 2914
Because it is preferable to slaughter an animal with sound eyes and ears, this does not mean that it is forbidden to sacrifice an animal with (minor) defects in the eyes or ears.
Sayyiduna Ali (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) commanded us to carefully examine the ears and eyes (of the sacrificial animal).
Hadith Referenceصحيح ابن خزيمه / جماع أبواب ذكر أفعال اختلف الناس فى إباحته للمحرم، نصت سنة النبى صلى الله عليه وسلم أو دلت على إباحتها / 2914
It is narrated from Hazrat Hujayyah bin Adi that a person asked Sayyiduna Ali (may Allah be pleased with him) about the sacrifice of a cow, so he replied that seven people can share in the sacrifice of a cow. He asked, "What if the horn is slightly broken?" He replied, "There is no harm in that." He then asked, "What is the ruling regarding lameness?" Sayyiduna Ali (may Allah be pleased with him) replied, "If it can walk to the place of sacrifice, then there is no harm." He further said, "And the Messenger of Allah (peace and blessings be upon him) commanded us to carefully examine the animal's eyes and ears (to ensure there is no defect in them)."
Hadith Referenceصحيح ابن خزيمه / جماع أبواب ذكر أفعال اختلف الناس فى إباحته للمحرم، نصت سنة النبى صلى الله عليه وسلم أو دلت على إباحتها / 2915