High Index materials will crack or chip around the drill mount of rimless frames. Maybe not today, maybe not tomorrow, but they will eventually crack. Avoid high index materials in drill mount frames. We know a reputable lab that claims the Seiko 1.67 is less prone to this problem, but we still steer our patients who need high index lenses into semi-rimless frames.
Trivex is your best option for rimless drill mount frames. Wont crack or chip around the drill mount.
Polycarbonate is probably your second best bet, but even it will eventually crack like high index lenses, just not as quickly. Another possible issue with polycarbonate is that the drilled hole can be prone to stretching over time, making the drill mount loose.