Epsom Handicap favourite Happy Clapper has firmed from $4 to $3.80 after drawing barrier four in the 14-horse field but second elect Egg Tart is in doubt with an eye irritation.

The Chris Waller-trained mare firmed from $5 to $4.80 after drawing gate one but failed an examination on Tuesday by Racing NSW veterinarian Dr Craig Suann.

He said at this stage the mare is not fit to race on Saturday and he will inspect her again on Wednesday to see if the problem has improved.

The dual Oaks winner is one of five Waller-trained acceptances for the Epsom with Comin' Through drawing barrier 12.

Comin' Through, to be ridden by Hong Kong champion Joao Moreira from gate 12, eased from $7 to $8 after firming on Monday from $11 when the TAB took a large bet on the four-year-old.