Retinopathy of prematurity (ROP) is a disease where unwanted blood vessels grow on a premature baby’s retina. A baby is premature when born before 31 weeks. The usual gestation period lasts 38-42 weeks. The growth of blood vessels in the eye is usually complete a few weeks before birth.
The retina is tissue located at the back of the eye. It sends signals to the brain after sensing light to enable vision. The growth of abnormal blood vessels on the retina can later lead to significant loss of vision or even blindness. Both eyes are usually involved in ROP which is a leading cause of vision loss in children.
ROP falls into 5 stages. Babies in stage I and II are called ‘prethreshold’ while those in stage III to V are called ‘threshold.’
- Stage I - The abnormal growth of blood vessels is mild. The infants recover without treatment and the disease does not progress.
- Stage II - The abnormal growth of blood vessels is moderate. Like those in stage I, these children eventually regain normal vision as soon as ROP disappears.
- Stage III - In this stage, the abnormal blood vessel growth is severe as the vessels grow away from their normal path along the retina’s surface. They grow towards the middle of the eye. The disease will resolve on its own without treatment in some children. Nevertheless, those with plus disease (blood vessels enlarge and get twisted) need treatment. Treatment may prevent a retinal detachment.
- Stage IV - A partial retinal detachment occurs when the abnormal blood vessels tug away at the retina. This action dislodges the retina from its usual position on the wall of the eye.
- Stage V - At this stage, the retina has wholly detached and the disease has reached its final stage. Without treatment, the baby may develop severe visual impairment or even blindness.
Also Known As
- Retrolental fibroplasia (obsolete)
Causes and Risk Factors
The causes of ROP have not yet been established. One school of thought holds that ROP develops when abnormal blood vessels grow in the retina. The eye usually grows rapidly in the last 12 weeks of pregnancy. Growth of the retina is complete about a month after a baby is born.
It is also thought that exposure to different agents like oxygen, bright lights, temperature changes and medicine can contribute to the development of the blood vessels in the eye.
The following are the risk factors that might contribute to ROP:
- Babies with a low birth weight of three pounds or less
- How soon the birth occurs. For example, a baby born at 28 weeks is likely to develop ROP than a baby born at 32 weeks
- Premature infants with health issues such as anemia, breathing problems, lack of Vitamin C and have had blood transfusions
Signs & Symptoms
ROP signs are invisible to the naked eye. They are located deep inside the eye. Only an ophthalmologist is trained to recognize and treat ROP. He/she will use special instruments to spot the signs.
Eye care professionals usually examine newborn babies for ROP soon after birth. However, the disease may not manifest immediately after birth. It may become visible several weeks after birth. For this reason, the professional will recheck a premature baby 4 to 6 weeks after birth.
Treatment of ROP is directed towards stopping the growth of abnormal blood vessels in the retina.
The eye doctor will initially allow the disease to go away on its own. Even then, the baby will be monitored closely. If, however, the abnormal blood vessels continue to grow, several medical treatment options can be pursued. One way is to inject the eye with medication to stop the unwanted blood vessel growth.
The doctor can also use cryotherapy to destroy part of the retina. The surgeon uses a freezing cold instrument to try and stop the growth of the abnormal blood vessels.
In scleral buckle, a band made of silicone is placed and tightened around the eye. The band prevents the vitreous gel from tugging at the scar tissue. This action allows the retina to resume its normal position. This treatment is offered to stage IV and V babies. The scleral band will be removed months or years later to prevent myopia.
ROP that results in a partial retinal detachment may not need treatment. It may resolve on its own. However, the doctor may recommend treatment for severe cases that might threaten to proceed to stage V.
Laser surgery (laser photocoagulation) can help to burn away the vessels on the edges of the retina.
In ROP stage V, the surgeon performs vitrectomy to remove the vitreous and in its place put a saline solution.
ROP usually goes away on its own as the infant grows. Those who develop stage I and II of the disease (about 90% of those born with ROP) recover entirely without permanent damage. Otherwise, the child can have severe vision loss or even go blind without treatment.
Frequent check-ups by an ophthalmologist are necessary for babies with ROP.
Patients with ROP can develop myopia (nearsightedness). They also face a risk of retinal detachment, strabismus or amblyopia. Glaucoma is another likelihood in ROP patients. Administering eye drops, wearing sunglasses, using an eye patch and surgery may help to treat these conditions.
Both laser treatment and cryotherapy can destroy some side vision in the process of treating ROP.
Though challenging to attain, the prevention of ROP involves preventing premature births.