Distortion from inside the Bell Jar

In class today, we talked about how Sylvia Plath's mother attributed The Bell Jar's less than flattering depiction of herself and other presumably realish people to an effort on Plath's part to document the distortion of truth experienced by people suffering from mental illness. Conflict of interest behind this statement aside, I think that it's interesting to think about how (and if) Esther's bell jar (so to speak) warped her (and by extension our own) perception of the Book's world.
We know that her judgement of other people can be a little harsh. She yells at Joan that she hates her when Joan's been nothing but nice. She also has a tendency to blame her own problems (and the problems that society imposes on her) on individuals. She blames the unpleasant, confining and autonomy-lacking nature of motherhood (and womanhood in general) on Buddy (calling him a hypocrite) who is not responsible for (though certainly benefits from, and perhaps perpetuates on a small scale) the system. She blames her career-related indecision and need to chose (a bad combination that will yield no figs at all) on Jay Cee, claiming that Jay Cee told something terrible to her when really all she did was ask about Esther's plans for the future.
But are these views a result of her mental illness? I can see a healthy (albeit somewhat frustrated) mind making these judgments. For one thing, they're not factual inaccuracies so much as odd, emotionally ridden opinions. For another, Jay Cee is an appropriate representation of the flaws in the limiting track to adulthood that she's following and Buddy is a good representation of sexist double standards; there is some legitimacy to Esther pinning these issues on them.
So is the bell jar warping her views of the world, or providing her insight into the true nature of things?
For the most part, during her decent into insanity (or rather the bell jar's decent onto her), the narrative remains strangely objective and, since the narrator has overcome her depression, there is theoretically some sort of system for potential filtration of straight-up factual inaccuracy (her older, sane self).
Even so, there are instances during which Esther is clearly perceiving things incorrectly. She claims that she can't read. Since she's obviously not illiterate this indicates some sort of issue between her brain and her eyes. Potentially even more troubling than this is that she keeps informing people that she can't read while obviously reading things. The headlines from her tabloids provide a significant part of the structure of the narrative during her illiteracy. She can read, she just can't read the intellectual things that she used to, which suggests a deeper problem. Similar to this is her supposed inability to sleep. She insists that she's not sleeping, but if she had actually gone for the number of nights that she claims with no sleep she would be dead.

"'I can't sleep. . .'
They interrupted me. 'But the nurse says you slept last night.' I looked around the crescent of fresh, strange faces.
'I can't read.' I raised my voice. 'I can't eat.' It occurred to me I'd been eating ravenously ever since I came to."
All of her complaints about her body failing her are ill-founded. I think that she perceives these physical issues because the bell jar is messing with her perception. Interestingly, it's actually messing with her perception of herself, not the outside world as the metaphor of a piece of glass between her and everything else would seem to suggest. Although, I suppose, in a sense, anything physical and removed from her conscious mind (like these problems seem to be) could be blocked out by the bell jar. 
Adding to the list of Esther's strange ideas under the influence of depression:
eating raw eggs and ground beef is acceptable, personal hygiene is too habitual to be worth it, slitting your wrists would be perfect if it didn't involve ruining your beautiful wrists. 

Esther's illness doesn't seem to manifest in ways as serious or concrete as straight up hallucination, but it certainly effects her opinions of others, normalcy and even herself.