Methodology used in calculating model outputs using Age Related Eye Disease Study (AREDS) and other data
| Simplified model calculations: |
| (1) Multiplying: (census data)×(incidence/prevalence)×(life expectancy). This gives the annual surviving prevalence and incidence numbers. |
| These numbers were then multiplied by: |
| (Incremental AREDS visual acuity events figure)×(calculated utility figure). This gives annual incremental utilities, enabling quality adjusted life years (QALYs) to be calculated. |
| (Incremental AREDS neovascular events figure)×(% of lesions applicable for treatment estimate)×(% actually treated estimate)×(unit cost). This gives the annual incremental laser or PDT cost saving associated with the reduced use of the relevant therapy. |
| (2) The total number of people screened by optometrists was calculated from census and unit cost data and accrued to the treatment arm alone. |
| (3) The cost of ongoing antioxidant and zinc treatment for all AREDS category 3 and 4 was calculated on an annual basis from screened survivors and accrued to the treatment arm alone. |
| (4) Final cost utility output = relevant cost/QALY. |