Well, it's time to check in once again with one of my favorite investment themes for the long-term. I don't specifically look for investment opportunities only within a favored investment theme, but when I come across new companies that look attractive, their ratings are bolstered if they fall into one of my preferred industries.

If you didn't already know, one of my favorite long-term investment themes is the eye care business. We're not trying to find a handful of "ten-baggers" here (although that would be nice). We're trying to identify great companies with long-term wealth creating potential.

Among them that have been written about in this column are LCA-Vision (NASDAQ/LCAV), IntraLase (NASDAQ/ILSE), Luxottica Group (NYSE/LUX), and Coastal Contacts (TSX/COA).

The smallest of these companies is Coastal Contacts. This great company sells contact lens supplies over the Internet. Every quarter, the company is able to acquire new customers, and it boasts a very high customer retention rate for its products. This signals to me that customers really like dealing with this company.

Luxottica Group is based in Italy, but operates around the world. This company manufactures eye glass frames, operating in both the wholesale and retail markets. The company is licensed to manufacture most of the top branded eyewear, and even owns many eyewear retail chains so it can control distribution and prices. This larger company is one of the best in the world at what it does.

LCA-Vision is all about laser eye surgery. More and more people are opting for this surgery, and from an investment standpoint, the industry can't be ignored as part of the broader eye care investment theme.

Finally, IntraLase is a high-tech manufacturer of lasers that are used in laser eye surgery procedures. This mid-sized company is growing fast, but the stock hasn't done anything for the last two years. This is because it was too expensively priced when it listed on the stock market. I think that, in the not-too-distant future, the company's business operations will catch up to the stock's valuation on the market, and there will be some wealth creation going forward.

There are lots of great companies to consider for investment in the eye care investment theme. If I was creating an equity portfolio with a ten year time horizon for investment, I would most certainly include a few picks from the eye care industry. The positive demographics for this industry are indisputable.