Annex 2

Screening for severe retinopathy of prematurity

The following guidelines for screening for severe ROP are proposed.

1. What is severe ROP?
Severe ROP is stage 3 or 4 acute ROP, which does not usually regress. The threshold for treatment is stage 3 disease, involving 5 or more contiguous or 8 or more cumulative clock hours.

2. Which babies?
Severe ROP is almost completely confined to the following groups:
(a) birth weight < 1500 g
(b) £ 31 weeks gestational age at birth
(c) no sickness criteria, e.g., apparently healthy, but falling into one of the above groups

3. When to examine?
Infants of 25 weeks or less gestational age at birth should be examined:
(a) 7 weeks postnatally,
(b) every 2 weeks thereafter until 36 weeks post-menstrual age, and after this only if indicated by clinical appearance.

Infants of 26 weeks or more gestational age at birth should be examined:
(a) 7 weeks postnatally
(b) at 36 weeks post-menstrual age, or within a week or so of this age if to be discharged from hospital around this time. For many in this group, one examination will suffice.

The timing of screening is critical, particularly since the time window for treatment is only about 2-4 weeks. The normal examination undertaken very early may have no screening value and once the infant has been discharged it may be too late for treatment.

4. Examination technique
(a) Pupillary dilatation
(b) Indirect ophthalmoscopy.

SELECTED WHO PUBLICATIONS OF RELATED INTEREST

Guidelines for programmes for the prevention of blindness. 1979 (47 pages)

Strategles for the prevention of blindness In national programmes. A primary health care approach. 1984 (88 pages)

Methods of assessment of avoidable blindness. WHO Offset Publication, No 54, 1980 (42 pages)

The provision of spectacles at low cost. 1987 (30 pages)

Field guide to the detection and control of xerophthalmia. 2nd ed Sommer, A 1982 (58 pages)

Vitamin A supplements: a guide to their use In the treatment and prevention of vitamin A deficiency and xerophthalmia. 1988 (24 pages)

Guide to trachoma control. Dawson, C R. et al 1981 (56 pages)

Conjunctivitis of the newborn: prevention and treatment at the primary health care level. 1986 (31 pages)

Accidents In childhood and adolescence. The role of research. 1991 (224 pages)

Further information on these and other WHO publications can be obtained from Distribution and Sales, World Health Organization, 1211 Geneva 27, Switzerland