As medical science has evolved, ever younger and smaller babies born prematurely have been saved.
In the 1940’s and 1950’s many premature babies were presenting with blindness due to damaged and detached retinas. This condition was named “retrolental fibroplasia”.
During the late 1950’s studies were performed which identified oxygen as a particularly troublesome factor in causing the disease. It was believed that due to the fact that the relative state of low oxygenation experienced by a fetus in the mother’s womb was required for normal retinal development which takes place during the last 12-14 weeks of pregnancy.
The name of the disease was later changed to Retinopathy of Prematurity, which is translated into a simple language that we can all understand means “damage to the retina suffered by babies born prematurely”.
ROP is caused by disorganized growth of retinal blood vessels which may result in scarring and retinal detachment. ROP can be mild and may resolve spontaneously, but may lead to blindness in serious cases. As such, all preterm babies are at risk for Retinopathy of Prematurity. Low birth weight an gestational age and exposure to oxygen therapy are additional risk factors.
If diagnosed properly through regular eye examinations and treated timeously ROP does normally not lead to blindness.
Oxygen
Oxygen is administered to a premature baby either via a tube inserted into the lungs via the throat (intubation), headbox or CPAP (nasal prongs). Health workers are required to constantly monitor oxygen concentration levels in the gas /air administered to the baby as well as in your baby’s blood (this is done by way of pulse oximeter (a device placed on the skin which measures various things in your blood – and provides a reading of oxygen saturation (measured as a percentage – %)) and also by drawing and analyzing blood samples (giving a reading of oxygen – blood/gas tension).
Although it is often contended that oxygen is not the only risk factor related to ROP and that there are no definitive “safe” levels of oxygen that should be maintained in a baby’s blood, it has been proven in an overwhelming number of studies that oxygen is the predominant factor in causing ROP and that very high levels of oxygen saturation and oxygen–blood/gas tension must be avoided to prevent ROP.
Treatment of the eyes
In the late 1980s studies were performed in the United States in which babies presenting with ROP were constantly monitored and treated at various stages of the development of ROP. The result of this study was the following:
- An international classification of the progressive stages of the disease;
- A universally accepted screening and treatment protocol (an indication of when and how the eye should be treated at various stages of the disease’s development)
- A responsibility to refer high-risk babies to an ophthalmologist
- A responsibility to examine young eyes and perform certain procedures to save eyes at risk of developing blindness.
- An indication of which babies are at high risk of developing ROP
There are various authorities that differ on the risk profile of various babies. The current internationally accepted regimen is that all babies born at a postmenstrual age of fewer than 33 weeks or weighing less than 1500g or above the aforementioned criteria but who have received prolonged supplemental oxygen or had a stormy neonatal course should be examined referred to and examined by an ophthalmologist for the development of ROP in order to enable timely treatment to prevent blindness. The South African National Department of Health has adopted this policy.