Campaigners claim that 20,000 people will be condemned to blindness each year following a "cruel" and "appalling" decision by the health watchdog.
The National Institute for Health and Clinical Excellence (NICE) has come under intense pressure to approve the drugs Lucentis (ranibizumab) and Macugen (pegaptanib), which are known as anti-VEGF drugs, for use on the NHS.
The drugs treat wet age-related macular degeneration (AMD), which affects around a quarter of a million people in the UK.
NICE has issued draft guidance recommending that Macugen should not be used at all on the NHS.
It also only recommends Lucentis for about one in five patients with wet AMD, who have a particular type called predominantly classic subfoveal choroidal neovascularisation (CNV).
It recommends Lucentis for use only when both eyes are affected, and only for use in the better-seeing eye.
Campaigners said this effectively means patients will only be treated once they have gone blind in one eye.
The Royal National Institute of Blind People (RNIB) said it is "outraged" by NICE's ruling, which is still open to consultation. A final ruling on the drugs is expected in September.
RNIB's head of campaigns Steve Winyard said: "This preliminary guidance is worse than we ever imagined it could be.
"Anti-VEGF drugs have the potential to halve the number of people going blind each year and patients in the UK who can benefit from them must all have them - and quickly."