[Avodah] blinded by the light?

[Rich, Joel via Avodah]

There’s a fascinating Ran on the Gemara in Kiddushin 31a concerning R’Yosef being blind in which he states that R’Yosef blinded himself so as not to have to see things outside of his 4 amot. Why wasn’t this considered chovel (wounding self) even if done indirectly? Even if not chovel, should/may one do something which limits his ability to do mitzvoth (any Torah ones perhaps)?
Ramban Kiddushin 31a
ורב יוסף פתח ונסתמא הוה כדאמרינן באגדה משום דלא מצי קאי בנפשיה דלא לאיסתכולי בר מד’ אמות דיליה,

Kt
Joel rich


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