SQL optimization - WHERE SomeField STARTING WITH ...

The SQL database servers I have worked with cannot use and index for a
SELECT of the form

SELECT * FROM ATABLE
WHERE AFIELD LIKE ?

because there is no way to know the location of the wild card until the
parameter value is known. InterBase and Firebird allow

SELECT * FROM ATABLE
WHERE AFIELD STARTING WITH ?

which is equivalent to LIKE  'ABC%' and will use an index on AFIELD. Is
there a similar syntax in PostgreSQL?

Bill