Retinopathy of prematurity is an acquired abnormality which appears on premature infants (cases that gestation is less than 35 weeks) weighing below 1500gr at birth. In general, when the birth weight is less than 2500gr the infant is at risk of developing retinopathy of prematurity.
In high weight premature (birth weight greater than 1500gr) and more than 32 weeks of gestation the disease’s incidence is rare. The lower the birth weight, the higher risk for this type of retinopathy according to ophthalmologists.
Nowadays, advances and progress at neonatology are very high, both in terms of medical knowledge, but also in terms of equipment as well. Thus, newborns who have premature birth weight of 600gr or 700gr can survive. However, the risk of developing retinopathy of prematurity is greater. Apart from weight and duration of pregnancy, there are also other factors, which play an important role in the appearance of the disease.
The main factor is the oxygen supply. The premature infants are placed in an incubator because they have an immediate need of oxygen to survive. The oxygen supply in these cases avoids any brain damage.
On the other hand, oxygen supply may increase the risk of retinopathy of prematurity. Thus, the main issue is to maintain the oxygen in adequate levels for the infant’s survival, as far as possible without affecting their eyes. Studies have shown that if the pressure of the arterial oxygen is always at 90mmHg or higher, then we may notice contraction of retinal blood vessels, especially those in the region, in which they are not well developed yet, due to prematurity.
The development of technology as well as doctors and nurses’ knowledge and education, in both public and private hospitals in Greece, may achieve a balance that ensures the survival of very low weight premature to have least disturbance in their eyes.
Moreover, the administration of cortisone by the obstetrician in case of imminent birth and the administration of a relatively new drug (surfactant factor) by the neonatologists to premature infants who have respiratory problems in the first days of their life, help to improve their lung function. As a result, this is a way to limit the duration and the level of the administered oxygen, so that we can avoid the disease’s development.
Retinopathy of prematurity predisposing factors
- High levels of oxygen supply at incubators
- Apnea
- Intracranial hemorrhage
- Transfusions
- Sepsis
Retinopathy of prematurity diagnosis & treatment
Retinopathy of prematurity is characterized by abnormal development of blood vessels (neovascularization) and fibrous tissue in the retina (photosensitive tissue where the image is depicted and the signal is transferred to the brain). These conditions may lead to retinal detachment and blindness.
At initial stages ophthalmologists observe the condition without interfering, because in many cases the disease is self-treated. If the disease does not regress, we can administer vitamin E intramuscularly, although it is not generally accepted that helps to inhibit the disease’s progression.
In advanced stages of the disease the ophthalmologist may diagnose tractions that may appear at eye’s fundus. At this stage there is a high risk of retinal detachment. The ophthalmologist can then intervene surgically or by laser (photocoagulation) or cryotherapy. Each of the surgical treatments has both advantages and disadvantages, so the doctor has to decide which therapy is more appropriate in each case. In general photocoagulation is more preferable because of fewer complications.
Overall we can understand how necessary is the presence and examination of an ophthalmologist in a premature infant in order to prevent serious problems. We have to notice that premature infants have to be examined also after leaving the hospital, even if they don’t have serious ophthalmological problems, because in these cases the risk of strabismus or some refractive errors (such as myopia) is higher, in comparison with full-term children.