Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Ciena (Nasdaq: CIEN) dropped 16% in intraday trading today after reporting a disappointing earnings miss and issuing a disappointing outlook.

So what: Investors disconnected from Ciena's network after the company reported non-GAAP EPS for the second fiscal quarter of -$0.24, well short of the consensus estimate of -$0.11.  GAAP EPS was -$0.66. Revenue of $418 million grew 65% year over year, largely because of the acquisition of part of Nortel Networks (OTC: NRTLQ.PK), but was at the low end of guidance and missed the consensus forecast of $429 million.

Now what: The CEO blamed the weakness on expenses related to entering new geographies and serving new industries. Several senior management changes were announced as the company turns its focus from integrating Nortel to a "drive toward sustained profitability." The phrase "drive toward" suggests red ink will continue to flow in the near term and analyst estimates are overly optimistic. For the current quarter, management expects revenue of $435 million to $455 million, less than the consensus forecast of $456 million, and adjusted gross margin in the "low 40s," an improvement from 39.7% in the just-reported quarter.

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Fool contributor Cindy Johnson does not own shares of any company named above. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.