Retinopathy of prematurity
| Retinopathy of prematurity | |
|---|---|
| Classification and external resources | |
| Specialty | ophthalmology |
| ICD-10 | H35.1 |
| ICD-9-CM | 362.20, 362.21 |
| OMIM | 133780 |
| DiseasesDB | 11442 |
| MedlinePlus | 001618 |
| eMedicine | oph/413 ped/1998 |
| MeSH | D012178 |
Retinopathy of prematurity (ROP) or Terry syndrome, previously known as retrolental fibroplasia (RLF), is a disease of the eye affecting prematurely born babies generally having received intensive neonatal care, in which oxygen therapy is used on them due to the premature development of their lungs. It is thought to be 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 it may lead to blindness in serious cases. As such, all preterm babies are at risk for ROP, and very low birth-weight is an additional risk factor. Both oxygen toxicity and relative hypoxia can contribute to the development of ROP.
By the fourth month of pregnancy, the foetal retina has begun to develop vascularization. Such formation of blood vessels appears to be very sensitive to the amount of oxygen supplied, either naturally or artificially. In rare cases ROP has been found in some patients with a mutation in the NDP gene, which is normally associated with the more formidable Norrie disease.
Various risk factors contribute to the development of ROP. They are:
During development, blood vessels grow from the central part of the retina outwards. This process is completed a few weeks before the normal time of delivery. However, in premature babies it is incomplete. If blood vessels grow normally, ROP does not occur. If the vessels grow and branch abnormally the baby develops ROP. These abnormal blood vessels may grow up from the plane of the retina and may bleed inside the eye. When the blood and abnormal vessels are reabsorbed, it may give rise to multiple band like membranes which can pull up the retina, causing detachment of the retina and eventually blindness before 6 months.
Normally, maturation of the retina proceeds in-utero, and at term, the medial portion(Nasal retina)of the retina is fully vascularized, while the lateral portion(Temporal retina) is only incompletely vascularized. The normal growth of the blood vessels is directed to relatively low-oxygen areas of the retina, but the vessels remain in the plane of the retina and do not grow into the vitreous humor. If excess oxygen is given, normal blood vessels degrade and cease to develop. When the excess oxygen environment is removed, the blood vessels rapidly begin forming again and grow into the vitreous humor of the eye from the retina.
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