The rebate has been slashed by 5 per cent under changes introduced on January 1, with a goal to save about $90 million over the next four years.

Optometry Tasmania director of education Andrew Hogan said the federal government had also lifted a fee cap, so optometrists could charge whatever they wanted.

"That's great because it gives optometrists freedom to set their own fees, to look at their own cost structures and look at their own business," Mr Hogan said.

"But the net result is going to be that bulk billing will drop and more patients will face out-of-pocket costs because essentially optometrists are going to have to charge above the scheduled fee to recover that income they're not getting from Medicare anymore."

Mr Hogan said people under 65 without symptoms would only be eligible to claim a Medicare rebate for an eye examination every three years, instead of every two.

He was concerned that people would delay eye checks under the changes, and the opportunity for early intervention would be lost.

"Going to the optometrist and having a general check-up is one of the absolute best ways of saving the health budget, because for pretty much every eye condition there is, early detection makes it easy to fix," Mr Hogan said.

A federal health department spokeswoman said the revenue from the initiatives would be invested in the Medical Research Future Fund.

The spokeswoman said there was a provision for patients under 65 to have a second or subsequent consultation within three years if it was needed.