If your mother is over 65, she can claim Attendance Allowance for help with personal care due to poor eye sight. Details here;
http://www.direct.gov.uk/en/Disabled...rt/DG_10012425
Disability Living Allowance is claimed by those under 65 for help with poor mobility and/or personal care. Details her;
http://www.direct.gov.uk/en/Disabled...rt/DG_10011731
You can claim other benefits as a carer if you stop work. This is more complecated to advise about here and so you should contact your local CAB for a interview and benefits advice.