You can apply for Disabled Students’ Allowances (DSAs) to cover some of the extra costs you have as a student because of a mental health problem, long term illness or any other disability.
You can get the allowances on top of your other student finance. You will not need to repay DSAs.
Please see the UK Government website, here.
There is a handy guide available for students with impaired vision about applying for DSA from Disability Rights UK, here.