All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Generally speaking there is nothing wrong with the Imamate of the blind or the deaf according to the view of the majority of scholars from the four schools of Fiqh and others. Al-Mardaawi, the Hanbali scholar, may Allaah have mercy upon him, said: "If an individual combined both blindness and deafness, his Imamate is valid according to the sound opinion of scholars."
Their Imamate is valid because their defects do not affect any of the prayer actions or conditions.
However, the Hanafi and the Hanbali scholars explicitly stated dislike of the Imamate of the blind; Al-Mardaawi, may Allaah have mercy upon him, said: "The seeing person is worthier to lead the prayer according to the Hanafi doctrine."
The Maaliki scholars stated the recommendation of the Imamate of other than the deaf and the dislike of the Imamate of the deaf. The Maaliki scholar Al-Hattaab, may Allaah have mercy upon him, said, “The deaf person should not lead the prayer since he may forget something during the prayer then when his followers notify him by saying 'Subhaan Allaah', he will not hear them so this would invalidate the prayer."
The Shaafi‘is held that the blind and the seeing person are the same in terms of reward, because nothing distracts the blind so he is more submissive while the seeing person can see the Khabath (impurities) so he can avoid it.
The preponderant opinion – and Allaah Knows best – is that the blind and the seeing person are equal in terms of leading the prayer. This is the view of the Shaaf‘is and the Maaliki researching scholars, because the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, appointed ‘Abd Allaah ibn Umm Maktoom, a blind man, as his successor in Al-Madeenah. Anas narrated that the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, appointed ‘Abd Allaah ibn Umm Maktoom, a blind man, as his successor in Al-Madeenah twice, and he led them in prayer. [Ahmad; Al-Arnaa’oot: Hasan]
Furthermore, the preponderant opinion pertaining to the deaf is the view of the Maalikis, since he cannot hear the Tasbeeh of men or the hand clapping of women if he erred in prayer.
Allaah Knows best.