DES MOINES, Iowa—So close and yet so far. It’s a frustration being felt by Americans who thought the finish line to their working life was almost in sight.

The financial crisis that toppled major Wall Street banks and snarled credit markets around the world has also taken a toll on nest eggs, forcing people to rethink when—and even if—their savings will allow them to retire.

More than half of people surveyed in an Associated Press-GfK poll released Wednesday said they worry that they will have to work longer because the value of their retirement savings has declined.

Denise Edwards, 62, now expects to work for at least another decade selling condominiums because of the damage to her and her husband John’s retirement savings.

“We just have to work for as long as possible. And we’re going to have to count on our (two) daughters,” said Edwards, who lives in a Virginia suburb of Washington.

In the last four years, Edward’s IRA has hovered at about the same level, and the couple’s other savings of less than $1 million have taken a double-digit hit this fall. They also still owe $425,000 on a house with a market value of $650,000.

The meltdown in the markets comes as pensions are being eliminated. The burden is increasingly on individuals to manage their own 401(k) plans and invest in the market.

In 1980, 60 percent of workers were covered by defined-benefit pension plans and just 17 percent relied on defined-contribution plans, such as a 401(k), according to the Center for Retirement Research at Boston College.

By 2004, the numbers had changed dramatically: 11 percent of workers were covered by defined-benefit plans and 61 percent were covered by defined-contribution plans.

“I think what this catastrophe in the financial markets highlights is how vulnerable this approach to retirement makes people,” said Alicia Munnell, director of the center. “Their welfare depends on market gyrations. They can be very responsible and still end up being hurt.”