Table 1.
Summary of outcome measures reported in the Collaborative Normal-Tension Glaucoma Study (CNTGS) (1998a/b) under the intention-to-treat (ITT) and post hoc (per-protocol) analytic frameworks
| Measure | Control group | Treatment group | Notes |
|---|---|---|---|
| Randomized eyes (ITT population) | 79 | 66 | |
| Progression events under ITT | 31/79 (39%) | 22/66 (33%) | All events included, time zero = randomization |
| Eyes progressing before IOP reduction target was reached | N/A | 11 | Excluded from per-protocol analysis after baseline shift |
| Number of eyes used in per-protocol survival curves | 79 | 61 | Treatment arm excludes early progressors and eyes not achieving 30% reduction |
| Progression events after baseline shift (per-protocol) | 28/79 (35%) | 7/61 (12%) | Time zero = IOP stabilization in treatment arm |
| Eyes developing cataract during follow-up | 11 (14%) | 23 (38%) | Treatment substantially more affected |
| Progression events counted after cataract censoring | 21/79 (27%) | 8/66 (12%) | Cataract-related visual decline censored from analysis |
All values are taken from published CNTGS reports. The table is intended to clarify how changes in baseline definition and censoring rules affected the number of progression events counted in each arm