http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed

VISX Clinical Trials

Understanding pre-market approval and labeling differences of two leading customized ablation platforms: a call for reform at the FDA.

Wachler BS, Hiatt JA. J Refract Surg. 2004 Sep-Oct;20(5):S588-92. Excerpt from the full text:

VISX reported that 97.7% (84/86) of eyes had UCVA of 20/20 or better at 12 months. These 86 eyes represent only 24.5% of patients. Accountability is reported to be 95.6%, despite the fact that 70.7% (248/351) of patients were labeled “not yet eligible” for analysis at 12 months.

In the VISX trial, 13 eyes were excluded from the data analysis because they required retreatments (12 within the study, 1 outside the study) as these 13 eyes had UCVA of 20/32 or worse. Adding these eyes to the 12-month data, UCVA of 20/20 can be recalculated to be 84.8% of eyes (84/99) at 12 months; this is in contradistinction to the 97.7% reported with exclusion of these 13 eyes that saw 20/32 or worse without correction.

The addition of these 13 eyes still only accounts for 28.2% (99/351) of 12-month results from patients enrolled in the clinical trial; the refractive outcomes for >70% of the study population are not reported.