Ciena (CIEN) narrowed its third-quarter loss on Thursday but fell short of expectations, as higher sales that merely met the Street couldn’t offset continued macroeconomic headwinds that caused customers to delay orders.

Shares of the Linthicum, Md.-based maker of communications networking equipment opened Thursday’s session down about 11% to around $14.95.

The maker of optical switches for voice, video and data traffic that is used by telecom carriers like AT&T (T) and Verizon Communications (VZ) posted a loss of $29.8 million, or 30 cents a share, compared with a year-earlier loss of $31.5 million, or 33 cents.

Excluding one-time items, Ciena lost $4.1 million, or 4 cents a share, two cents worse than average analyst estimates in a Thomson Reuters poll.

“We are experiencing the effects of ongoing macroeconomic challenges and slower than expected roll-outs of new design wins,” Ciena CEO Gary Smith said in a statement. “However, our approach to the market is working … and our view of the long-term opportunity is unchanged.”

Revenue for the three months ended July 31 was $474.1 million, up 8.9% from $435.3 million, matching the Street’s view. By segment, sales grew across all but one of its four primary business segments, led by packet-optical transport.

Looking toward the current fiscal fourth quarter, Ciena sees revenue either falling or remaining flat quarter-over-quarter in the range of $455 million to $480 million, which is below the consensus of $499.7 million.

Ciena earlier this year said that it expected business to improve in the second half of 2012.

Follow Jennifer Booton on Twitter at @Jbooton