Retinopathy of Prematurity (ROP)

INTRODUCTION

Retinopathy of Prematurity (ROP) is a retinal disorder of low birth weight premature infants. It can be mild with no visual defects, or it may become aggressive with new vessel formation and progress to retinal detachment and blindness. Nearly one third to half of neonates undergoing screening may show some degree of ROP which fortunately regresses on its own in majority of affected infants, in a few it progresses to the stage of retinal detachment and blindness. Timely screening and treatment of ROP can prevent blindness and minimise visual handicaps.

RISK FACTORS OF ROP

Various risk factors contribute to the development of ROP. They are:

1. Prematurity
2. Low birth weight
3. High exposure to oxygen for prolong period
4. Apnoea
5. Sepsis
6. Anaemia
7. Cardiac defects
8. Multiple blood transfusion
9. Respiratory distress syndrome
   Birth weight and gestational age – most important risk factors for development of severe ROP
10. infants with very low birth weight are at significantly higher risk of developing severe ROP that requires treatment. Similarly, the severity of ROP is inversely proportional to gestational age. Present evidence shows that low birth weight and gestational age are the most predictive risk factors for the development of ROP

In general, other risk factors are surrogate markers of sickness in the baby. Therefore, sicker the baby higher is the risk.

SCREENING OF ROP

1. whom to screen

Screening should be carried out for the infants with either of the following

1. Birth weight less than 2000 gm
2. Gestational age less than 34 weeks
3. Gestational age between 34 to 36 weeks but with risk factors such as:
   1. cardio-respiratory support
   2. Prolonged oxygen therapy
   3. Respiratory distress syndrome
   4. Chronic lung disease
   5. Fetal haemorrhage
   6. Blood transfusion
   7. Neonatal sepsis
   8. Exchange transfusion
   9. Intraventricular haemorrhage
   10. Apnoea
   11. Poor postnatal weight gain
4. infants with an unstable clinical course who are at high risk (as determined by the neonatologist or paediatrician).

2. When to screen

1. Should receive first screening at 4 weeks of birth.
2. Infants with period of gestation less than 28 weeks (gestation age) or less than 1200 grams birthweight should be first screened at 2-3 weeks after delivery.

To simplify, ROP screening should be done at 4 weeks after birth. However, if any baby was delivered earlier than 28 weeks of gestation or birth weight less than 1200 gm should have a ROP screening at 2-3 weeks after birth.

DURATION AND FREQUENCY OF SCREENING

Initial examination

1. Follow-up examinations are recommended by the examiningophthalmologist on the basis of retinal findings
2. In general, the screening examinations will continue at least every two weeks until:
   1. vascularisation of the retina reaches normal completion, or
   2. Until ROP regresses, or
   3. Until ROP requiring treatment develops.

PLACE OF EXAMINATION

1. Neonatal Intensive Care Unit (NICU)
2. Special Care Neonatal Unit (SCNU)
3. Ophthalmologist’s clinic for stable infant.

TYPE OF TREATMENT

1. Laser therapy.
2. Cryotherapy
3. Advance Retinal Surgery.

AIM OF TREATMENT

The aim of treatment is to reduce the incidence of retinal detachment and blindness.