The answer below is phrased in the feminine, and is applicable to immersion either for conversion or for taharat hamishpacha. The same halachot apply to a man immersing for conversion, in which case any necessary assistance should of course be offered by another man.
A blind woman is responsible for all of the preparations for immersion. If she needs assistance with a particular task, she should ask for help from another woman (not her husband). Theoretically, a blind woman is capable of inspecting herself completely by feeling her body for any barriers. Practically, she may need assistance with the inspection and should ask the attendant for help when necessary.
If she needs assistance entering and exiting the water, another woman may escort her. If she needs assistance immersing, she may hold on loosely to the wall or a bar, making sure her entire body is immersed. If she feels it is necessary to hold on to someone for assistance, she may hold on loosely to another woman’s arm. The assistant should first her wet her arm with the mikveh water to ensure that the area where the blind woman grasps her is touching mikveh water.
In the case of a blind woman immersing for taharat hamishpacha, the Shulchan Aruch (YD 196:7) explicitly discusses the question of performing bedikot. She performs the required bedikot and has them examined by another woman (or by her husband if he is sighted and does not find it distasteful). Given the added difficulty involved in having someone else examine the bedikot, it is permissible for a blind woman to do only one bedikah per day during the shivah neki’im. It may also be possible for bedikot to be reviewed online through Tahor App; visually impaired women can contact them directly to arrange this.
Please feel free to get back to us with any further questions.
This response was updated on 19 February, 2020.