Gentex ( GNTX), a maker of automatic-dimming rearview mirrors and fire-protection products, said Thursday that its second-quarter earnings rose nearly 5% from the year-ago period. The Zeeland, Mich., company earned $27.2 million, or 18 cents a share, in the quarter, compared with $26.0 million, or 17 cents a share, a year ago. Adjusted for stock option expenses, earnings were $28.6 million, or 19 cents a share. Analysts polled by Thomson First Call were expecting earnings of 17 cents a share in the most recent quarter. Second-quarter revenue rose 7.6% from a year ago, in line with analysts estimates, to $142.4 million. ''The automotive industry continues to be very challenging, and it is a difficult area to predict future sales and unit shipment volumes, particularly given the current macroeconomic environment," Gentex said. "We currently expect unit shipment growth in the third quarter to be about flat to up 5% compared with the third quarter of 2005, and expect about 5% to 10% unit shipment growth for all of calendar year 2006." Shares of Gentex were trading at $13.53, up 48 cents or 3.7%.