Healthcare developer Neuroptix raised $18.5 in second-round funding from Inventages Venture Capital, Launchpad Venture Group and several undisclosed investors. It plans to use the money to push an eye test that could be used to diagnose Alzheimer’s disease through the last phases of clinical trials. The post-money valuation of the round was $41 million.

Based on Acton, Mass., the company may raise another round of financing in order to commercialize its finished product. The system, called Neuroptix Sapphire, uses a device in tandem with an eye drop to check for the presence of certain proteins indicative of the disease. It is currently in pre-clinical testing, but has the potential to detect Alzheimer’s at very early stages, the company says.

Neuroptix last raised funds in 2007, receiving $1.6 million from Launchpad, Maine Angels and Quan Ventures. It also snagged a $1 million milestone payment last year for work it did with Merck.