| Variable | Cost per patient (range) (£) | Distribution for sensitivity analysis |
| Level 1 manual grading (D-grade nurse) | 1.48 (1.14–2.11) | Gamma (α 10.95, β 0.135) |
| Additional QA costs (manual grading) | 0.20 (0.15–0.25) | Gamma (α 16, β 0.0125) |
| Level 1 automated grading | 0.14 (0.07–0.29) | Uniform (min 0.07, max 0.29) |
| Level 2 grading (E-grade nurse) | 1.41 (1.12–1.98) | Gamma (α 9.95, β 0.142) |
| Level 3 grading (consultant ophthalmologist) | 3.08 (2.57–3.85) | Gamma (α 47.43, β 0.065) |
| Slit-lamp grading (F-grade nurse) | 4.42 (3.16–5.69) | Gamma (α 130.24, β 0.034) |
| 6 month re-screen (manual system) | 13.95* | |
| 6 month re-screen (automated system) | 12.70* | |
| Ophthalmology referral | 65.00† |
*Based on fixed screening cost plus grading costs per patient in Grampian.
†Average cost for an ophthalmology outpatient visit in Scotland (http://www.isdscotland.org/isd/files/Costs_R044X_2005.xls).