Does disability impact on prospects of employment in academia? The impression I get in my field of research (theoretical chemistry) is that candidates for postdoc and more permanent research positions are judged partly upon their publication record. I suspect this is true of other fields, particularly the sciences.

I suffer from a long term chronic illness which means currently I cannot work full-time. I manage 75% of full-time hours  working on my PhD currently, so while I am well enough to do research, I am not well enough to do as much as I'd like. I am concerned that, should my health not improve, this will prove problematic as I try to move from being a student to an employee. My academic output would likely be less than an able-bodied person in the same position. While it may be of the same quality, there would be less of it. 

There is legislation in many places that prevents discrimination against disabled people, but I suspect this would not apply where candidates are being judged based on previous academic output. My worry is that because academic employment seems so performance/output-oriented, I will be left behind, even if my work is of good quality. 

Thoughts and experiences regarding how disability is treated in academia, particularly with regards to selecting candidates for a new position, would be greatly appreciated. I would also welcome advice on how to mitigate the possible issues arising from this.

I was initially unsure whether to post this, as it would be possible for potential employers to identify me from this posting. However, I think this topic is important to discuss and there are potentially other PhD students in the same situation as me.
Self-identifying a disability at some stage during the interview process is usually in your best interest. Being upfront with a potential employer can make all the difference, especially because of the legal protections it affords you in most academic settings. It's also important because then expectations are properly set at the beginning of the process, rather than having to "adjust" later on.

Additionally, many application processes (at least in the EU) allow for self-identification of illnesses and handicaps that could "slow down" one's career. This allows one to "lengthen" the eligibility clocks for many programs. This helps to ameliorate the problems you mentioned of being judged against a cohort that has had more time to work.