What happened? Tuesday is shaping up to be a good day for shareholders of STAAR Surgical (NASDAQ: STAA), which manufactures implantable lenses, and Prestige Consumer Healthcare (NYSE: PBH), which markets over-the-counter (OTC) healthcare products. As of 1:30 p.m. EST today, STAAR Surgical stock was up by 14.7%, while Prestige Consumer's stock was up by 7.7%. The catalyst was recently announced changes to two market indexes involving both companies. So what Starting on Jan. 29, STAAR Surgical will replace Prestige Consumer in the S&P MidCap 400, an index that tracks 400 mid-cap companies in the U.S. equity market. It is one of the most widely followed mid-cap indexes, and eligibility requirements include a certain level of liquidity and financial viability. Meanwhile, on the same day, Prestige Consumer will take the place of Foundation Building Materials (NYSE: FBM) in the S&P SmallCap 600. Image source: Getty Images. While changes to more-famous indexes such as the S&P 500 tend to attract more attention, new additions to smaller ones like the S&P SmallCap 600 and the S&P MidCap 400 can also generate some excitement among investors, and that seems to be what's happening today with STAAR Surgical and Prestige Consumer. Now what For long-term investors, these changes mean little in the grand scheme of things, and so does the boost that STAAR Surgical and Prestige Consumer are experiencing as a result. The important thing to focus on is the prospects of both these healthcare companies. 10 stocks we like better than STAAR SurgicalWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and STAAR Surgical wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of November 20, 2020 Prosper Junior Bakiny has no position in any of the stocks mentioned. The Motley Fool recommends STAAR Surgical. The Motley Fool has a disclosure policy.Source