That there is an eye-issue with super lesser/ super butter / lesser butter exists, and occurs at quite a high frequency, this is uncontroversial i think.

About my source for the issue causing blindness, well, i remembered someone on this forum owns some that are blind, and Satomi knows who:

Quote Originally Posted by satomi325 View Post
I don't know the ratio or statistics, but there are cases where BELs(Super Lesser) are blind.
Snakesrkewl has a pair who are blind.
and even if they dont go blind.... I dont think im leaning out of the window too far when i speculate that deformed eyes likely lead to blurred vision. Which, in humans, gets fixed with glasses or contact lenses, but snakes dont like to wear those I dont have sources for that, but it seems plausible that oddly shaped eyes will be less likely to focus properly.

and panic, i dont know, its known that blind BPs do very well in captivity and can eat and breed very well and you dont even notice it when handling them. So we are far away from panicland anyway. By contrast, spine kinks or severe neuro or skull deformities are the really nasty stuff, eye issues not so much.

its not something you must avoid at all costs, but with the BEL gene complex you have so many alternatives (like super het russo / white diamond, like TheSnakeGeek mentioned), so its so easy to avoid that i say: Why not simply avoid it?