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Sample size calculation per arm for an equivalence trial of operative intervention for severe vision loss in idiopathic intracranial hypertension (IIH).
| Equivalence limit of MRD | 80% power | 90% power |
|---|---|---|
| Alpha of 0.025 | ||
| 2.9° (25% of SD of treatment effect) | 336 | 416 |
| 5.8° (50% of SD of treatment effect) | 84 | 104 |
| Alpha of 0.05 | ||
| 2.9° (25% of SD of treatment effect) | 274 | 346 |
| 5.8° (50% of SD of treatment effect) | 64 | 87 |
MRD = mean radial degrees.
