On Tuesday, STAAR Surgical (STAA.US) saw its premarket shares surge over 15% to $27.15. The catalyst behind this movement was Alcon's announcement that it has increased its acquisition offer for STAAR Surgical to approximately $1.6 billion in total equity value, up from the previous $1.5 billion.

Under the revised terms of the agreement, Alcon will purchase all outstanding shares of STAAR Surgical at $30.75 per share in cash, higher than the prior offer of $28 per share. Alcon stated that the revised deal now represents a 74% premium to STAAR Surgical’s 90-day volume-weighted average price and a 66% premium to its closing price on August 4, the day before the merger announcement.