Dear Editor,

On the recommendation of a number of authors, our department aims to follow up children born prematurely for at least two years [1-3]. Those children who are screened as infants for retinopathy of prematurity (ROP) receive an appointment for review with our orthoptists at six months of age. The orthoptic department until two years of age then follows them up. At this point they receive an appointment at a consultant ophthalmologist’s clinic for cycloplegic refraction. The intention of this is to screen children for treatable ocular abnormalities such as amblyopia and myopia, which have been shown to be more prevalent in this group of children [3,4].

Cases

We examined the records of 92 children assessed as requiring screening for ROP, born at our hospital from June 1998 to February 2002. 57% were male, 27% were twins, average gestational age was 29.5 weeks and average birth weight was 1.224kg. 26% showed intra-ventricular haemorrhage on cranial ultra-sound scan and 3% had evidence of peri-ventricular leukomalacia.

Any stage of ROP was recorded in 14% of which one child required treatment.

Of note was the poor attendance for follow-up in this affluent city. Although the intention was to follow all these children for at least two years, 36% had been lost to follow-up by 18 months of age.

Also of note was the relatively low pick-up rate of treatable ocular abnormalities. Six cases of amblyopia were detected, however five of these were associated with a manifest squint, for which the parents may well have sought attention even without screening. Only one case was secondary to anisometropia and therefore treated with glasses. That child was a twin born at 28 weeks gestation and intra-ventricular haemorrhage was noted on cranial ultra-sound scanning. No retinopathy of prematurity was noted, but final refraction, at 5 years, was Right eye: -0.50/+1.50x90, Left eye: - 3.00/+0.75x90 and visual acuity was Right eye: +0.20, Left eye +0.30.

Comment

We ask the question whether the hospital resources we use, at this district general hospital, to follow up these children, are justified for early identification of essentially one case of anisometropia, which would normally be identified at routine visual screening in this region.

The children we included met the criteria set out by the Royal College of Ophthalmologists for screening for ROP [5]. However, we are aware that in comparison to a tertiary referral centre our sample would include fewer children of exceptionally low birth weight. This may in part account for the relatively low prevalence of ocular abnormalities, which we found.

References

1. Schalij-Delfos NE, de Graaf MEL, Treffers WF, et al. Long term follow up of premature infants: detection of strabismus, amblyopia, and refractive errors. Br J Ophthalmol 2000;84:963-967.

2. Holmström G, el Azazi M, Kugelberg U. Ophthalmological follow up of preterm infants: a population based, prospective study of visual acuity and strabismus. Br J Ophthalmol 1999;83:143-150.

3. Darlow BA, Clement RS, Horwood LJ, et al. Prospective study of New Zealand infants with birth weight less than 1500g and screened for retinopathy of prematurity: visual outcome at age 7-8 years. Br J Ophthalmol 1997;81:935-940.

4. Saunders KJ, McCulloch DL, Shepherd AJ, et al. Emmetropisation following preterm birth. Br J Ophthalmol 2002;86:1035-1040

5. Williams C. Retinopathy of prematurity. The Royal College of Ophthalmologists of London – Focus 2000;15.