Workers at Bausch + Lomb in Waterford have been urged by the company owner to accept the proposed cost-cutting deal.
Workers have also been told that if they accept the deal they will not be asked for more concessions.
Michael Pearson, CEO of Valeant, issued a letter to each of the 1,100 employees this afternoon.
Union members at the Waterford facility are due to vote on the company's proposals this weekend.
In the letter, Mr Pearson said that two weeks ago he sent them a note stressing their preference as a company to keep the Waterford plant open and to continue to invest in the facility.
He praised the breadth and depth of the expertise of staff, the contributions that Waterford has made to Bausch + Lomb's contact lens business but said to achieve certain goals required a step change reduction in labour and other costs so that the company can be competitive.
"I believe we have a deal on the table that will enable management to fulfill our commitment to keeping Waterford open and viable for the long term.
Through long days and nights your union leaders, and our team on the ground, engaged in intense but constructive negotiations to develop a deal that works for us and will hopefully work for you," he said.
The CEO of Valeant said the company's proposed changes meet the minimum threshold laid out at the outset of their discussions and it was now up to staff to make their decision.
"If you agree to the terms laid out, I reaffirm our commitment that we will not ask for more concessions, and that we will continue to invest in Waterford in the long term. We also expect the Government/IDA to honour their commitments as part of this agreement," he said.
The company says their plans indicate that if employees take a 7.5% pay cut on €41,000 (the standard basic rate at the plant), they will be down €3,075 per annum.
They will also lose a bonus payment equivalent of 4% foregone (on this salary this would be €1,640 pa).
The annual gross loss between pay cut and lost bonus would be €4,715. Twice the annual gross loss is €9,430.
Valeant say they are committed to giving employees on such a salary €9,430 each as a net-after-tax lump sum, with half paid now and half within 12 months.
The company says this is equivalent to not being affected by pay and bonus cuts for nearly four years.