The S&P 500 was up 0.5% in midday trading to 2,415.77

The Dow Jones Industrial Average was up 0.4% to 21,087.02.

The NASDAQ was up 0.8% to 6,210.86.

The yield on a 10-year Treasury bond fell 0.5% to 2.26%.

The price of gold was up 0.2% to $1,259.

HEALTHCARE

Aerie Pharmaceuticals Inc. in Irvine was up 30% to $52.30 and a $1.8 billion market cap. The development-stage company said a phase-3 clinical trial on an eye drop for glaucoma showed positive results.

Presbia PLC in Irvine was down 11% to $2.58 and a $44 million market cap. The Ireland-chartered company sells a refractive lens implant to treat farsightedness in CE Mark countries in Europe, but the product is not yet approved in the U.S.

RETAIL

Tilly’s Inc. in Irvine was up about 5% to $10.18 and a $294 million market cap in a second day of share price growth after a positive quarterly report.