Sql Isnull()

I have the following Select statement:

select CustomerID, Name,

CASE
  WHEN (CONVERT(varchar(10),(ISNULL(BuyDate, '')), 110)='01-01-1900') THEN (' ')
   ELSE (CONVERT(varchar(10),(ISNULL(BuyDate, '')), 110))
END as BuyDate

from Customers;

BuyDate --it's datetime field in the Customers table

ISNULLL(BuyDate, '')  returns 01-01-1900 if BuyDate contains NULL.

Is there BETTER WAY to re-write the below piece of my sql sttement ???

CASE
  WHEN (CONVERT(varchar(10),(ISNULL(BuyDate, '')), 110)='01-01-1900') THEN (' ')
   ELSE (CONVERT(varchar(10),(ISNULL(BuyDate, '')), 110))
END as BuyDate


Thanks