A terrified doctor feared she had been blinded when liquid was squirted in her face as she cycled along the seafront.
It was one of two similar attacks in two weeks and police are linking both attacks.
The GP told police and ambulance staff she had been squirted in the eyes with a pepper-based liquid.
She said the liquid was burning her eyes and that she could barely see.
The attack happened in Kingsway, Hove, on Saturday shortly after 5pm.
The doctor told police a man spat at her as she cycled past the end of Langdale Road.
Inspector Mark Powles said: "She stopped and turned to ask the man what was wrong.
"He produced a syringe and squirted a pepper-based liquid in her face and then ran off along Langdale Road."
An ambulance crew treated the victim at the scene by washing her eyes thoroughly and she did not need hospital treatment.
Police said the attack followed another on a 19-year-old woman cyclist who was riding a bike in Davigdor Road, Hove on September 1, when a man used a water pistol to squirt a similar pepper-based liquid into her eye.
She recovered her sight after receiving treatment at the scene from an ambulance crew.
In both cases, the attacker was described as aged 40-50 years old, with greying white hair and about 5ft 6ins.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article