Table.
Cases of visual field defect attributed to treatment with vigabatrin in prescription event monitoring study 1991-4 and long term follow up study 1998-9
| No (%) cases | |
|---|---|
| Prescription event monitoring study | |
| Questionnaires sent | 17 307 (100) |
| Questionnaires returned | 11 769 (68) |
| Questionnaires with clinical data | 10 178 (59) |
| Questionnaires with clinical data, for living patients | 10 033 (58) |
| In these 10 033 living patients:- | |
| Patients with objective evidence of visual field defect | 4 (0.04) |
| Long term follow up study | |
| Questionnaires sent for patients taking vigabatrin at end of prescription event monitoring study | 7 228 (100) |
| Questionnaires returned | 6 809 (94) |
| Questionnaires with clinical data* | 5 074 (70) |
| Questionnaires with clinical data, for living patients | 4 741 (66) |
| In these 4741 living patients: | |
| Objective evidence of visual field defect | 36 (0.8) |
| Visual field defect “probably” associated with vigabatrin | 14 (0.3) |
| Visual field defect “possibly” associated with vigabatrin† | 16 (0.3) |
*
Patients no longer registered with general practitioner=1136; blank questionnaires or duplicate patients=599.
†
Includes one case from the prescription event monitoring study.