Many premature babies are affected by lung problems

Babies born before they reach full-term often have under-developed lungs, and need to be given oxygen.

But the oxygen can cause the over-production of blood vessels in the eyes, leading to blindness - a condition called retinopathy of prematurity (ROP).

However, US scientists say a protein found in placenta could protect babies' eyes.

This is a way of expanding our understanding of the disease Professor Alistair Fielder, Imperial College

And in separate research, UK scientists are developing computer software to help identify ROP.

Currently, babies have to be seen by specialists before the condition can be diagnosed.

Around 200 premature babies are affected by the condition every year in the UK.

But experts say figures are higher in areas including Latin America and Eastern Europe, where neonatal care is less advanced.

Blindness

In ROP, exposure to high levels of oxygen destroy immature retinal blood vessels.

But when children return to breathing normal air, the body overcompensates and creates far too many new vessels, which can leak blood.

This can cause the retina to become detached and even lead to blindness.

The US research team, from Harvard Medical School and Children's Hospital in Boston carried out tests on mice.

They looked at a protein called VEGF - vascular endothelial growth factor - which has been shown to protect retinal blood vessels from being destroyed by oxygen therapy.

Scientists had hoped it could be used as a basis for a treatment for ROP.

But VEGF also causes the abnormal growth that leads to leaky vessels.

The researchers discovered a different growth factor found in placenta called PlGF-1 appeared to protect blood vessels against oxygen damage without the same side effects.

The team, led by Dr Lois Smith, suggest PIGF-1 could be the basis of a treatment to prevent premature babies developing ROP.

'Short window'

In the UK study, researchers from Kingston University are developing computer software to help doctors spot problems early.

Babies who have ROP have very narrow blood vessels in their eyes, which only specialists can spot.

It is hoped developing software which can analyse eyes automatically will make it easier for nurses and other healthcare staff to spot the condition as early as possible.

Dr Sarah Barman, who is leading the research, said: "There is only a short window of opportunity to treat infants who are suffering from retinopathy of prematurity.

"If it has gone too far, it cannot be cured.

"The improvements we can achieve in retinal imaging will ensure that doctors can detect problems early and decide whether or not to stop the abnormal growth of the blood vessels."

Alistair Fielder, professor of ophthalmology at Imperial College London, said both pieces of research could help premature babies affected by ROP.

He told BBC News Online: "The US work is very exciting and could herald a way of helping babies.

"We can't control VEGF, so this is a way of expanding our understanding of the disease and doing something about it."

The research was published in the Journal of Clinical Investigation.