A population-level post-screening treatment cost framework to help inform vision screening choices for children under the age of seven.

Purpose/background: Visual acuity (VA) screening in children primarily detects low VA and amblyopia between 3 and 6 years of age. Photoscreening is a low-cost, lower-expertise alternative which can be carried out on younger children and looks instead for refractive amblyopia risk factors so that early glasses may prevent or mitigate the conditions. The long-term benefits and costs of providing many children with glasses in an attempt to avoid development of amblyopia for some of them needs clarification. This paper presents a framework for modeling potential post-referral costs of different screening models once referred children reach specialist services.

Methods: The EUSCREEN Screening Cost-Effectiveness Model was used together with published literature to estimate referral rates and case mix of referrals from different screening modalities (photoscreening and VA screening at 2, 3-4 years and 4-5 years). UK 2019-20 published National Health Service (NHS) costings were used across all scenarios to model the comparative post-referral costs to the point of discharge from specialist services. Potential costs were compared between a) orthoptist, b) state funded ophthalmologist and c) private ophthalmologist care.

Results: Earlier VA screening and photoscreening yield higher numbers of referrals because of lower sensitivity and specificity for disease, and a different case mix, compared to later VA screening. Photoscreening referrals are a mixture of reduced VA caused by amblyopia and refractive error, and children with amblyopia risk factors, most of which are treated with glasses. Costs relate mainly to the secondary care providers and the number of visits per child. Treatment by an ophthalmologist of a referral at 2 years of age can be more than x10 more expensive than an orthoptist service receiving referrals at 5 years, but outcomes can still be good from referrals aged 5.

Conclusions: All children should be screened for amblyopia and low vision before the age of 6. Very early detection of amblyopia refractive risk factors may prevent or mitigate amblyopia for some affected children, but population-level outcomes from a single high-quality VA screening at 4-5 years can also be very good. Total patient-journey costs incurred by earlier detection and treatment are much higher than if screening is carried out later because younger children need more professional input before discharge, so early screening is less cost-effective in the long term. Population coverage, local healthcare models, local case-mix, public health awareness, training, data monitoring and audit are critical factors to consider when planning, evaluating, or changing any screening programme.