12-month workload estimates for cataract surgery in Theni population (≥40 years) in hypothetical scenarios based on goals of reducing cataract burden
| Scenario | Goal | Current utilisation % (A) | Additional utilisation to achieve goal % (B) | Overlap between current and additional utilisation % (C) | Net utilisation % (D=A+B−C) | Number of persons to be treated (E=D×population of 540 078) | Estimated CSR based on 2021 projected population of 1.319 million (F) |
| 1 | Meet current demand | 3.10 | 0 | 0 | 3.1 | 16 742 | 12 689 |
| 2 | Meet current demand and eliminate present burden of PVABE<3/60 | 3.10 | 0.34 | 0.20 | 3.24 | 17 517 | 13 276 |
| 3 | Meet current demand and eliminate present burden of PVABE<6/60 | 3.10 | 0.64 | 0.41 | 3.33 | 18 001 | 13 643 |
| 4 | Meet current demand and eliminate 1/5th of present burden of PVABE<6/12 | 3.10 | 1.98 | 1.63 | 3.46 | 18 667 | 14 148 |
Column A: Based on last row of table 4.
Column B: Based on last row of table 2. In particular, the 1.98 in scenario four is obtained as 1/5×(1.51+7.77+0.30+0.34).
Column C: Of the 221 study participants who obtained cataract surgery in the last 12 months (table 4), data on PVABE was available for 149. Of these, 14 (0.20% of 7127) had PVA<3/60, 29 (0.41% of 7127) had PVA<6/60, and 116 (1.63% of 7127) had PVA<6/12, where 7127 is the study sample size.
Column D: Since participants in column C are included in both columns A and B, we remove the duplication by subtracting.
Column E: Theni district population (≥40 years) is projected to grow to 540 078 in 2021 from the 2011 level of 425 376. This is done by applying the 10-year growth rate of 26.96% of Tamil Nadu population (≥40 years) obtained from https://main.mohfw.gov.in/sites/default/files/PopulationProjectionReport2011-2036-upload_compressed_0.pdf.
Column F: Theni district population for 2021 based on 10-year Tamil Nadu population growth rate of 5.9% applied to 2011 population of 1 245 899.
PVABE, presenting visual acuity in the better eye.