SOME SEVEN OR eight million children under the age of 5 die every year, in developing countries, from drinking polluted water. Thirty or 40 million people in those countries are blind -- some from vitamin deficiencies, some from infection. While unemployement is rising in the rich industrial countries, in the Third World unemployment and underemployment are already in the hundreds of millions. What can be done about that?

Then there is the less visible damage done to poor nations by the constant sense that their destinies are being managed from somewhere else. The real decisions always seem to be made by large institutions, public and private, with headquarters in another country -- usually to the north. When the South's grievances go unheard by them, there is no further appeal. What can be done about that?

The case for development aid, and the sharing of international power, is essntially a moral one. But it has always been sharply reinforced by the self-interest of the rich. The industrial countries know that poverty in the South eventually threatens prosperity in the North. People who live in North America, Japan and Europe understand the threat to stability, and even to peace, in the politics of impotence and desperation. They understand it, but they don't always pay much attention. Currently, preoccupied with oil and Afghanistan, they are paying very little attention. The Brandt Commission now strongly and urgently reminds them.

"Our report is based on what appears to be the simplest common interest: that mankind wants to survive, and one might even add has the moral obligation to survive," writes Willy Brandt, the former chancellor of West Germany and holder of the Nobel Peace Prize. His commission is 21 people, all of wide experience in public policy but none representing a government. They come from every continent and reflect a great variety of political views. Remarkably, they were able to agree on a substantial list of recommendations.

This report comes at a time when the rich countries, harassed by inflation and deficits, are not likely to respond quickly to its proposals for more generous aid. The prospect for a world agreement on oil pricing is poor. As for disarmament, the present trend is, lamentably, the other way.

And yet the Brandt Commission's description of the rising danger is correct and widely accepted. Its plan for an oil-pricing agreement, for example, was originally conceived to head off, in effect, the destructively rapid doubling of prices that has just taken place. If economies now stagnate in the Third World because of it, jobs will evaporate in the industrial countries, including this one, for which the Third World is a crucial export market.But there is a more pressing menace.

Americans have generally assumed that what counted in foreign policy was the strategic balance with the Russians and the alliances with Europe and Japan. If they were maintained, this assumption went, other responsiblities could be left to a lower priority or none at all. But the Iranian revolution is demonstrating the speed with which upheaval in the developing world can draw into it the great powers and their highest interests. It also suggests the vulnerability of a great power -- the United States -- to a smaller country's accumulated suspicions and resentments. For the doubters, Iran demonstrates the consequences of neglecting the claims that the Brandt Commission has addressed.