Which body parts warrant the biggest biotech venture investments?

Dow Jones writer Brian Gormley set out to find out the answer to that question, reviewing the venture data for biotech and med tech in Dow Jones' VentureSource database. He concluded that eye diseases warranted the biggest single wager on any particular organ, with a total of $849 million in venture bets on ophthalmology startups in the field. And $442.7 million more came in the first half of this year, indicating that there's been no letup in the action.

The eye represents one of those contained systems that investigators love to research. And anything related to sight is provided a very high value among patients. Ahead of its acquisition by AbbVie ($ABBV), Shire's new CEO Flemming Ornskov began to expand the company's ophthalmology pipeline. And Regeneron's ($REGN) success with Eylea has helped inspire new plays for gene therapies and more.

The ears are next on the most-popular list, warranting $114 million in investments for the first half after seeing $76.2 million for all of last year.

That's not a huge portion of the total, but ear ailments are getting some additional investments as more venture players focus on a better understanding of a very specific field. Tinnitus and other diseases are seeing some initial bets.

Cardiovascular bets are big--accounting for $709 million of VC's money last year--but that figure was well off an earlier pace. In 2011, the number was $1.1 billion.

Cardiovascular drugs require enormous trials for FDA regulators, who aren't about to let new drugs into the market without a very clean bill of health. The bigger the studies, as venture players found out with diabetes some years ago, the bigger the risk of blockbuster failure. And without much leverage for taking these drugs into Phase III, cardio drugs have a tougher case to make. Still, with a big market awaiting any heart drug that can appeal to an aging society, the $709 million investment in this field still ranks as a sizable piece of the overall pie.

The spine and orthopedics in general are also losing their luster with investors. Last year VCs bet a total of $479 million in the field, after seeing $1.14 billion in 2006. Regulatory delays have created a serious hurdle for this area of R&D, Gormley writes, making it harder to reach an approval and cooling down the earlier zeal. -- John Carroll, FierceBiotech (email | Twitter)