What happened

Shares of Glaukos (NYSE:GKOS), a medical-device company focused on glaucoma, fell 12% as of 3:25 p.m. EST on Tuesday on heavy volume. However, there wasn't any news that can help to explain the move. 

So what

Glaukos shares have been under pressure ever since management knocked down the company's growth projections in September.

Once upon a time, management was projecting that full-year sales would land between $162 million to $167 million. That range implied growth of 44% at the midpoint. However, the company later stated that changes in the reimbursement environment, hurricanes, and competitive pressure were going to make it hard for the company to hit that number. As a result, they dialed back their revenue guidance range to $155 million to $160 million. While that still represents strong year-over-year growth, Wall Street didn't take the update well.

With Glaukos expected to report third-quarter earnings results later today, it's possible that some traders believe that another downward revision to guidance could be on the way. That worry could be the source of today's carnage.

Business man looking worried at his laptop

Image source: Getty Images.

Now what

Glaukos' iStent put up impressive growth numbers since its launch a few years ago. However, that growth mostly came in the absence of competition. Now that Novartis' CyPass Micro-Stent is on the market, Glaukos is squaring off against a well-financed competitor.

Can the company keep its high growth rate going, or will investors be in for another round of disappointing news? We'll know more after the company reports its third-quarter earnings later today.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.