It’s neither our practice nor our inclination to write about health tech developers who abandon projects or new tech attempts that fail. Because Google’s health tech division Verily and Novartis’ Alcon eye-care division are the primary participants in the glucose monitoring smart contact lens project, this article differs from our normal coverage. We’re not picking on Google, Verily, Novartis, or Alcon. However, Verily’s recently announced hold on further developments in the heavily publicized project is a significant shift.

The joint effort between Verily and Alcon to embed sensors in contact lenses to monitor blood glucose levels began in 2014 as one of the Google health group’s initial projects. In the intervening years, according to Verily, the joint project developed new technologies. For example, the team demonstrated ways to to integrate electronics and sensors on contact lenses. Two projects with Alcon involved developing smart lenses for people with presbyopia — the loss of the ability to focus on close objects — and for implanting after cataract surgery. Over time, however, the group realized their work on glucose measurement using tears was based on a faulty premise. Verily and Alcon’s clinical studies showed inconsistent correlations between tear glucose and blood glucose readings. Interference from the biomolecules in tears and difficulties obtaining reliable tear measurements were just two of the significant challenges uncovered by the research.

So from this point, Verily intends to focus on developing miniaturized continuous glucose sensors with Dexcom, to continue work with Sanofi on technology for diabetes Type 2 patient management, and to work with Alcon on smart lens programs. But for now, it appears that non-invasive glucose measurement using tears may be a dead-end.