Seeability's link with the RNIB allows it to make use of the bigger charity's clout.
Recent figures show that the largest charities are pulling away from their smaller counterparts with less well-known brands. Income is becoming concentrated right at the top of the sector and medium-sized charities are feeling the squeeze.
Some middle-ranking charities have been swallowed up by larger ones, but there is a co-operative path that plays to the strengths of both kinds of organisation.
Seeability's partnership with the RNIB capitalises on the national clout of the latter's brand and thrives on the smaller partner's specialist knowledge and traditions. The two are collaborating to create an information service for people with learning disabilities, who are 10 times more likely to have sight problems than the rest of us.
Seeability says about 100,000 people with learning disabilities in the UK are suffering as a result of preventable sight loss.
The RNIB runs projects in Scotland through its Visual Impairment and Learning Disability Services, but recognised that these needed to be expanded across the UK. It chose to work with Seeability, a 205-year-old charity that specialises in helping blind and partially sighted people who have other disabilities.
The two charities will work on a national information service comprising a separately branded website, a telephone advice line and an email forum. They will also raise awareness with optometrists and hope to help as many as 30,000 people over the next three years.
"Both organisations recognised that there was a very big job to do out there and we could do it much better if we worked together," says Lucy Sargent, campaigns director at Seeability. "We are a very old charity and we bring great expertise in matters of multiple disability and visual impairment.
"RNIB can help us with brand leverage and its expertise with campaigning - which is where we want this project to be going in the long term."
Two information officers will be appointed, one at each charity. "We have a dual responsibility to raise awareness of this service," says Linda Mitchell of RNIB Scotland. "But the RNIB is recognised nationally as a provider of services and information for blind people. This is a powerful marketing tool."