Retinopathy of prematurity (retinopathia praematurorum) is a vascular proliferation of the retinal tissue (retina) that can occur in premature babies, especially babies born before 32 weeks’ gestation (SSW). Retinopathy of prematurity is classified into type 1 and type 2 and can be detected and treated early using screening tests.
What is retinopathy of prematurity?
Retinopathy of prematurity is a disease of the eye. In this case, there is damage to the retina that occurs only in premature infants. During pregnancy, the blood vessels of the retina form from the 15th week of gestation. Due to premature birth (before the 32nd week of pregnancy), the oxygen supply to the blood vessels changes. Due to this, excessive growth can occur in the vessels, which can result in changes in the retina as well as its detachment. Depending on the type of retinopathy of prematurity, the children may later need glasses or contact lenses (often because of myopia). However, retinopathy of prematurity can also result in more severe visual impairment or even blindness. Premature babies before 32 weeks gestation are particularly at risk. Babies whose birth weight is less than 1500 g or who require artificial ventilation for more than three days also have an increased risk of developing retinopathy of prematurity.
Causes
The cause of retinopathy of prematurity is insufficient development of the retina. Because the retina and its blood vessels do not begin to grow until the 15th/16th week, maturation is not complete until birth in the 40th week of gestation. Before birth, the baby is supplied with oxygen via the mother’s blood supply, so the oxygen content in the blood is much lower than after birth. In premature babies, the partial pressure of oxygen increases when the baby begins to breathe on its own. In case of breathing problems, the premature baby may need to be artificially ventilated, which increases the partial pressure of oxygen even more. Due to this excess oxygen, the sensitive, immature retina is damaged, blood vessels begin to proliferate and can sometimes even grow into the vitreous body, causing severe bleeding. Another danger in retinopathy of prematurity is detachment of the retina.
Symptoms, complaints, and signs
Retinopathy of prematurity caused by increased partial pressure of oxygen during oxygen ventilation of premature infants is divided into five stages. Up to stage II, these are mild forms of retinopathy that can also regress. However, if the retinal change is more advanced, irreversible damage can occur that can only be prevented by timely treatment. In stages I and II of retinopathy of prematurity, a demarcation line or raised border wall between the mature and immature retina is formed. From stage III of the disease, new vessels and connective tissue growths form at the edge of the boundary wall. The newly formed vessels grow from the retina into the vitreous. In stage IV, partial retinal detachment occurs. Stage V is characterized by complete retinal detachment. Without treatment, retinopathy of prematurity can lead to blindness. However, even with treatment or mild courses, later complications are possible. For example, defective vision may develop, in which distant objects are seen only blurred (myopia). Furthermore, the balance of the eye muscles may be disturbed, leading to strabismus (strabismus). The development of glaucoma is also possible, since the growths of connective tissue increase the intraocular pressure. In very rare cases, late retinal detachment occurs even years later.
Diagnosis and course
Retinopathy of prematurity is diagnosed by an ophthalmologist or pediatrician. Here, atropine is administered as drops into the eyes, resulting in pupil dilation. Once the dilation of the pupil is complete, further eye drops containing an anesthetic are administered. The eye is kept open with a so-called eyelid block. By means of a so-called ophtalmoscopy (ophthalmoscopy), the retina of the child is now examined. The examination is usually performed on premature infants from the 6th week of life.This examination should be checked several times. The course of retinopathy of prematurity can be described as good. If the disease is detected and treated in time, it has a good prognosis. Type 2 retinopathy of prematurity usually heals completely; in exceptional cases, small scars may remain on the retina, possibly leading to myopia. Type 1 retinopathy of prematurity can result in a so-called secondary retinal detachment in the further course – sometimes years later. If not treated in time, affected individuals may become permanently blind. To rule out late effects of retinopathy of prematurity, annual checkups with an ophthalmologist are mandatory at least until the child is 8 years old.
Complications
In retinopathy of prematurity, technically also called retinopathia praematurorum, the still immature retina suffers damage due to the too early increase of oxygen in the bloodstream. The vessels contract, causing the retina to be insufficiently supplied with nutrients and growth factors. If the constriction is not corrected, the vessels may close completely. As a result of retinopathy, there is an excessive proliferation of connective tissue outside the retina, which in some cases also involves the release of too many growth factors. These lead to proliferation of vessels into the vitreous body of the eye, which can cause retinal detachment. If retinal detachment is not treated in time, it can lead to blindness. Normally, both eyes are affected by retinopathy of prematurity. However, it is possible that the disease manifests differently in the eyes. The course of the disease also varies, but the greatest expression of symptoms is always around the calculated date of birth. Even if the course of the disease is only mild and there is no retinal detachment, the disease can have late consequences. In addition to glaucoma, strabismus, amblyopia or myopia may develop. In rare cases, delayed retinal detachment with subsequent blindness may also occur years later. However, to treat the disease, the administration of growth inhibitors would be necessary, but this would also stop the growth of the remaining organs.
When should one go to the doctor?
Premature infants are usually examined extensively by nursing and hospital staff shortly after delivery. In these routine examinations, all the developmental stages of the various human systems are closely examined and treated, since they are not yet fully mature. Usually, these measures detect retinopathy of prematurity at an early stage. If, nevertheless, changes are noticed in the newborn that have not been explicitly pointed out by treating physicians, discussion with the pediatrician should be sought. If the child’s visual disturbances are noticeable or the premature baby’s behavior is unusual, this is considered a cause for concern. If parents notice that the child’s reactions to visual stimuli are absent, they should pass on this observation. Contoroll examinations are necessary to determine the cause. If relatives can perceive abnormalities on the retina of the child’s eye, especially discoloration, these should be reported to the staff of the pediatric ward in the hospital. Bleeding from the eye or unusual fluids leaking from the eye must be medically examined and cared for. If there are deformities or other abnormalities of the retina or eye, asking a doctor is advisable. If the retina detaches or tears of the retina are evident, these perceptions should be reported to a physician.
Treatment and therapy
Treatment of retinopathy of prematurity depends on several factors. First, it is necessary to determine which type is present in retinopathy of prematurity and the stage of retinal damage. Type 1 is also referred to as retinopathy of prematurity plus desease. If this plus desease is not present, retinopathy of prematurity is classified as type 2. In type 2 retinopathy of prematurity, initially only regular check-ups are performed at very short intervals, as active therapy is not necessary in this case. If type 1 is diagnosed in retinopathy of prematurity, treatment must be started immediately.Depending on the severity of the retinal damage, it is treated under general anesthesia by cryocoagulation (icing) or by laser coagulation (laser treatment). In case of a very severe course or in case of secondary retinal detachment, which already results in blindness, surgery is rarely performed nowadays. Retinopathy of prematurity requires a complex and long follow-up. Regular follow-up examinations must be performed until the disease has been successfully treated (in type 1) or until the blood vessels and retina have fully matured (in type 2 retinopathy of prematurity).
Outlook and prognosis
If left untreated, retinopathy of prematurity can lead to complete blindness. If surgical measures are taken when retinal detachment has already occurred, they have moderate success. For a good prognosis, the disease should be detected and treated as early as possible. However, even with initially successful treatment, late effects can still occur in adulthood. Mild forms of retinopathy, in which no retinal detachment has occurred, may regress completely. However, many affected individuals remain severely myopic due to disease-related scarring in the retina. Distortion of the retinal vessels and displacement of the macula (point of sharpest vision) may also cause the patient to squint. Abnormal, rapid eye movements (nystagmus) may also occur. Possible late effects of retinopathy of prematurity include early-onset cataracts (clouding of the lens of the eye) and glaucoma (pressure damage to the eye). Scarring shrinkage of the entire eye can also lead to complete blindness on the affected side. Stress on the retina can cause holes or detachment even years after the disease. Retinal folds can also form or other changes to the retina can take place. Regular checkups by an ophthalmologist are recommended so that possible late effects can be detected and treated early.
Prevention
Preventive measures cannot be performed in retinopathy of prematurity. In the case of artificial ventilation, it is important to check the blood oxygen level regularly. However, with the help of ophthalmologic screening, a severe course of retinopathy of prematurity can be prevented. The screening is carried out on all premature babies born before the 32nd week of gestation. Thus, retinopathy of prematurity can be detected in time and treated successfully.
Follow-up
Regular ophthalmologic examinations are necessary both in mild forms of the disease that do not require therapy and after therapy has been performed for retinopathy of prematurity. These are performed at approximately weekly intervals until a clear regression of the disease is observed. However, the number and intervals of the examinations must be adapted to the individual course of the disease. If the course of the disease is satisfactory, the close-meshed examinations are usually completed when the retinal vessels have matured and the calculated date of birth has been reached. In addition, control examinations are performed at intervals of a few months until at least the age of six. Here, objective refraction determinations (objective determination of the refractive power of the eye) and orthoptic examinations are important (orthoptics belongs to the specialty of strabismus). However, late sequelae and complications of retinopathy of prematurity may still occur in adolescence or adulthood. These include pseudostrabismus (apparent strabismus), high myopia (severe nearsightedness), scars and holes in the retina, retinal detachments, pigmentation of the retina, glaucoma (glaucoma) and cataract (cataract). Without timely and adequate therapy, these late effects can possibly lead to blindness of the patient, which is why lifelong regular ophthalmologic care is necessary. Therapy for any late effects can be difficult and should therefore be provided at specialized treatment centers.
What you can do yourself
Parents should keep a close eye on their premature infant and consult the attending ophthalmologist or clinic as soon as possible if there are any changes in his or her (visual) behavior. Older premature infants who can already talk should also be watched closely by caregivers. It may be that the child describes a change in vision.Just as well, it may not because, for example, retinal detachment has happened to the amblyopic bad eye and the better eye has already taken over. Because retinal detachment from retinopathy of prematurity can happen later in childhood, adolescence, or adulthood, the warning signs of retinal detachment should be heeded. The processes in the eye due to retinopathy of prematurity cannot be prevented or controlled. The risk of retinal detachment can be reduced by avoiding pressurized breathing, heavy lifting, the risk of severe concussions, and falls as in some sports or fairground rides. Depending on the outcome of the retinal reattachment surgery, several options are available. If a child remains visually impaired, early intervention is advised. This will help to strengthen the child’s personality overall and provide strategies for playing and learning. Extensive information on this topic can be found in the “Ratgeber für Menschen mit Behinderung” (Guide for people with disabilities) published by the BMAS.