The Royal National Institute of Blind People says its concerned that proposed changes to Disability Living Allowance (DLA) could mean that some people with poor sight will have their benefits cut.
The consultation on the regulations for the new DLA closes today.
But the RNIB says that those who use a guide dog will automatically be given the full amount of mobility allowance. However those who choose to use a long cane instead, will not - even though they have exactly the same issues.
The charity also says it hopes the government will listen to their concerns about the draft legislation.
And it says that there is also a suggestion that people who have been visually impaired for longer would receive less benefit than those recently diagnosed.
The final regulations on Disability Living Allowance are expected to be revealed in the autumn.
A spokesperson for the Department of Work and Pensions said:
"Under PIP support will be focused on those who need it most, with a greater proportion getting the higher rates compared to DLA.
"We will introduce a new face to face assessment and regular reviews which will look at an individuals needs, rather than labelling them by their health condition or impairment.
"In the past DLA has been poorly managed so we now have a situation where there are hundreds of millions of pounds of overpayments and underpayments and the vast majority of people get the benefit for life without systematic checks to see if their condition has changed."