The Gherkin will be overtaken by the weird and wonderful characters of Alice in Wonderland for the cause later this week.
A Mad Hatter themed event to raise funds for the charity Fighting Blindness will take place on Thursday night with organisers seeking more help from firms with supplying raffle prizes.
More tickets are up for grabs too.
Cathi Harrison, founder and director of Para-Sols, has put together the fundraising party for pal Matt Levington, who was diagnosed with a degenerative eye disease, which left him unable to read or drive.
Mr Levington, in his early 20s, and who works for Cofunds, has Lebers Hereditary Optic Neuropathy. The disease, a relatively unknown condition, suddenly took hold, apparently out of the blue.
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Cathi said: "Everyone has been very supportive and we already have a number of brilliant raffle prizes.
"But I would like to encourage more people to buy tickets, both on the night and beforehand, any other available prizes would be very welcome.
"Fighting Blindness is a relatively small charity and is one of the few that actively help to support LHON sufferers.
"They are also leading pioneering research into potential cures for some strains of LHON and the ability to support this and the potential impact it can have on peoples lives is an amazing cause.
"It's great to be involved with a smaller charity where you can see the direct impact the fundraising can achieve."
Of the event, she said: "Its' a great opportunity to visit the top of the Gherkin and support an amazing charity at the same time.
"All will be revealed on the evening but it is a Mad Hatter theme - not at all a reflection on the organiser."
For more and to donate visit these sites www.eventbrite.co.uk/e/mad-hatter-champagne-tea-party-tickets-11969498091 and www.justgiving.com/CathiandVicky