Oftalmologia Pediátrica e Estrabismo

Retinopathy due to prematurity

Retinopathy of prematurity is a developmental disease of retinal vascularization, which
in prematurely-born babies is incomplete. The development outside the uterine environment may be anomalous, leading to alterations capable of destroying the eyeball structure and consequently to blindness.

The shorter the gestation time and the lower the weight at birth, the greater is the risk of appearance of this disease, and potentially the greater is its severity. All premature babies with less than 31 weeks of gestation and/or with less than 1250g of weight at birth are especially at risk. The risk is also increased in preterm babies with greater cardio-respiratory unstableness during neonatal period.
With the improvement of neonatal care, the survival of premature babies with less and less weight and gestation time has significantly increased. This fact leads necessarily to an increase not only of the incidence of retinopathy, but also of the more severe forms of this disease, capable of causing serious alterations in sight.

Retinopathy of prematurity is one of the main causes of blindness in children worldwide: it is the second cause in the USA and the first in some developing countries, such as China and countries of Latin America, where the increase of the survival of underweight newborn babies is accompanied with a relevant increase of the incidence of this disease. Among the treatable causes of blindness, retinopathy of prematurity is in the second position, after cataract.

The clinical characteristics, the factors of risk, the evolutional stages and the natural history of retinopathy of prematurity (ROP) are perfectly known owing to several multi-centre studies, from which the more relevant are “Cryo-ROP Study” and “ETROP”.
In these studies it was clearly proved that the treatment with cryotherapy or with laser is effective when applied in time.
Therefore, it is very important to create a system that ensures the examination and monitoring of all the infants at risk during critical periods, until the moment when the risk of blindness disappears.

In Portugal, about 1020 children are born with very low weight, every year, and with a high risk of developing this disease. Until the year 2000 only about 50% of these infants were examined by an ophthalmologist, but the last data indicate a progress to nearly 74%. The incidence of retinopathy observed is 20.4% in a population with an average weight of 1157g at birth.

These data lead to several considerations. First, this coverage is clearly insufficient and unacceptable in a country of Western Europe, ranked in the 28th position in the statistics of the “Human Development Report”. The main causes of this deficient coverage are the necessity of multiple examinations of each premature infant, implying time availability, associated with the lack of qualified human resources in the hospitals with neonatal units. Second, the tendency for an increasing incidence of this disease in Portugal, and to the appearing of more and more severe forms, leads to the necessity of more human resources and technical means to avoid the consequences of this. Thus, it is fundamental to implement a national plan for screening, recording and treating this disease.

The rules to carry out an effective screening, monitoring and treatment are well defined internationally: ophthalmological examinations and monitoring are obligatory for all the children born with less than 32 weeks of gestation and/or with less than 1500g of weight. The non-observance of this rule may imply, besides ethical issues, medico-legal problems to those responsible for childbirth health units.
Therefore, it is necessary to create in Portugal effective structures that ensure that all newborn babies are properly diagnosed, monitored and treated in due time.

The recent digital systems capable of recording images of the eye fundus and of sending them through a computer network, to observation centres with ophthalmologists experienced in the evaluation and treatment of this disease, facilitate the conception of a national plan for screening, recording and treating retinopathy. The quality and reliability of the last models of these equipments, with a wide-angle camera, make them a precious help to save time and to avail of qualified human resources, in shortage in our country.

In Portugal, nearly 20 hospitals have a neonatal care unit, where more than 20 underweight premature babies are born every year. The setting up of 20 digital recording units and the establishing of 3 observation centres strategically situated would enable to create an efficient national network that would ensure the examination of all the children at risk.

The existence of this type of equipments is recommended in neonatal care units with children at risk, in order to guarantee that examinations and treatment decisions are undertaken by qualified ophthalmologists.

Developed by Sistemas do Futuro