Sir,

Retinopathy of prematurity (ROP) is a potentially avoidable cause of childhood blindness, the stages of which have been defined by the International Classification of Retinopathy of Prematurity.1 In the United Kingdom, screening of at-risk babies (birth weight <1500 g or <32 weeks gestational age) occurs until vascularization is complete, or until disease progression mandates treatment.2, 3 It has been shown internationally that infants with different characteristics can develop severe ROP, associated with the level of the country's development, emphasizing that ROP screening programmes need to be appropriate for the local population.4 In light of this, we wished to evaluate if a pattern existed for ROP screening and treatment for our population, which could be affected by NHS work patterns.

It is commonly recognized that there is a steady monthly increase in the general population birth rate from January, with a peak in August and then a gradual decline to December. This has also been the pattern in Glasgow. We reviewed our theatre logbook and identified 129 ROP laser procedures from 1994 to 2010. In this time period we discovered a peak of treatment in September, with a lesser peak in February and June. This pattern was mirrored by the average screening events in the past 2 years (see Figure 1). This seasonal pattern of ROP has not been described before with reference to the NHS workforce, with peaks around the times of widespread junior doctor changeover in all specialties at the start of August and February.

Figure 1
figure 1

Graph illustrating average episodes of ROP screening per month and ROP treatment. Note the seasonal peaks—around the two time periods for widespread changeover of junior medical staff (and summer leave periods for senior staff).

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This seasonal trend may have implications for service provision and maintaining safe continuity of care at times of junior staff turnover (for referral and communication) and senior staff leave (for service delivery). Severe ROP requiring treatment is infrequent in the United Kingdom, yet this treatment is specialized, and should be performed by ophthalmologists with appropriate training and competence. It is the view of the Guideline Development Group for ROP that once identified, treatment should occur within 48 h.3 Clinicians providing ROP treatment should be aware that their workload will have seasonal variation, with peak times of service delivery for their population, and plan accordingly.