health · family: it worked in the lab
blood tells everything,nothing else can
Continuous health monitoring requires blood draws — no wearable can measure clinically actionable biomarkers non-invasively
Problem statement
Managing chronic diseases (diabetes, autoimmune disorders, organ transplant rejection) requires frequent measurement of blood biomarkers — glucose, drug levels, inflammatory markers, immune cell counts — through venipuncture or fingerstick blood draws. ARPA-H describes continuous monitoring as "an important and evasive goal of biomarker sensing." Existing continuous glucose monitors (CGMs) measure interstitial fluid (not blood), require subcutaneous insertion, and can only measure one analyte (glucose). Tear fluid contains many of the same biomarkers found in blood (ARPA-H names hormones, vitamins, and proteins), but no sensor technology can simultaneously measure multiple tear biomarkers continuously, at clinically relevant concentrations, without interfering with normal tear film function or vision.
Why this matters
ARPA-H's first disease target is dry eye disease, an underdiagnosed condition that it says affects at least 20 million Americans. ARPA-H also says many treatments require routine monitoring to follow disease progression and to adjust medication and dosing. Diabetics perform fingersticks or wear CGMs; transplant patients require repeated blood draws for immunosuppressant drug levels; autoimmune patients need periodic inflammatory marker panels. A wearable tear-based monitoring system that could continuously track multiple biomarkers would enable real-time therapeutic dose adjustment (closed-loop drug delivery), early detection of disease flares, and reduced clinical visit burden.
What’s been tried and why it hasn’t worked
Smart contact lenses for glucose monitoring have been pursued by companies and academic groups. Challenges for that approach include tear glucose concentrations that are lower than blood glucose and lag behind blood levels, and reflex tearing (from irritation, emotion, or wind) that can dilute biomarker concentrations. Electrochemical sensors embedded in contact lenses face biocompatibility, sensor stability, and power challenges at contact lens scale. Tear collection for laboratory testing is episodic, not continuous, and tear sample volumes are small. ARPA-H says that in-office testing of tear biomarkers is the current standard of care for diagnosing dry eye disease, that treatment adjustments are made only with a full exam and laboratory processing of tears, and that there are no existing technologies that continuously sample tears to diagnose or treat disease.
What would unlock progress
A wearable tear-contact platform (punctal plug, contact lens, or conjunctival insert) with integrated multi-analyte biosensors that can: (1) continuously sample tear fluid without disrupting the tear film or causing irritation; (2) detect multiple biomarkers simultaneously at clinically relevant concentrations; (3) transmit data wirelessly to a smartphone or closed-loop drug delivery system; (4) maintain sensor stability and calibration for days to weeks in the ocular environment. The ARPA-H OCULAB program specifically envisions a system inserted into the tear duct, paired with closed-loop medication dosing. The cited ARPA-H pages do not compare this with contact lenses; a device in the tear duct would sit away from the corneal surface, which may avoid the vision-interference challenge of contact lens approaches.
Entry points for student teams
A student team could characterize the correlation between tear and blood concentrations for a panel of clinically relevant biomarkers (cortisol, CRP, immunoglobulin A) using paired tear and blood samples from healthy volunteers, establishing the validation data needed for a tear-based monitoring system. An engineering team could prototype a miniaturized multi-analyte electrochemical sensor array on a flexible substrate, testing stability and sensitivity in simulated tear fluid. Relevant disciplines: biomedical engineering, analytical chemistry, ophthalmology, electrical engineering, materials science.
Genes
Structural cousins: stuck the same way, in other fields
Sources
ARPA-H, "Ocular Laboratory for Analysis of Biomarkers (OCULAB)," ARPA-H press release, "ARPA-H launches program to develop a tear-based biomarker measurement platform," 2024; accessed 2026-02-23 go to source ↗
Working notes
Notes made while writing and checking this brief, shown as written. They use working shorthand.
Related briefs: `health-longterm-implantable-glucose-sensor` (continuous glucose sensing challenges — tear-based monitoring is an alternative approach to the same underlying need); `health-pulse-oximeter-skin-tone-bias` (wearable biosensor accuracy challenges in diverse populations). The `failure:ignored-context` tag reflects that previous smart contact lens attempts designed sensors for the corneal surface without adequately accounting for the ocular environment: tear film instability, reflex tearing, limited power harvesting, and the physical constraints of a contact lens form factor. The tear-duct approach (OCULAB's strategy) represents a reframing that addresses this context. Source-bias note: ARPA-H frames the tear-duct device as a breakthrough form factor; whether a foreign body in the tear drainage duct will be tolerated chronically without complications remains to be demonstrated.
Reconciliation 2026-09-29: Site review round 5 read the whole write-up against its two cited sources. Both were fetched in full on 2026-09-29: the OCULAB program page at https://arpa-h.gov/explore-funding/programs/oculab, and the press release at https://arpa-h.gov/news-and-events/arpa-h-launches-program-develop-tear-based-biomarker-measurement-platform. A later press release linked from the program page, "ARPA-H program turns your eyes into smart health monitors" (March 3, 2026), was also read, at https://arpa-h.gov/news-and-events/arpa-h-program-turns-your-eyes-smart-health-monitors. (1) The Source line dated the press release 2025. The page says "Published October 18, 2024", so the year now reads 2024. (2) The text said "Over 129 million Americans have at least one chronic disease requiring ongoing biomarker monitoring." That figure is not in either source. The sentence now gives the figure the sources do give: dry eye disease, the program's first target, affects at least 20 million Americans. (3) The text said "The global biosensor market exceeds $28 billion, driven by demand for continuous, non-invasive monitoring." Neither source mentions a market size, so the sentence was removed. (4) The text said tears contain "hundreds of biomarkers that correlate with blood levels" and listed glucose, cortisol, immunoglobulins, cytokines and drug metabolites. Neither cited source gives a count, says that tear levels track blood levels, or names those five. The March 2026 press release says tears "contain many of the same biomarkers found in blood", and the program page names hormones, vitamins and proteins; the sentence now says that. (5) The text said no wearable or implantable system can continuously measure such biomarkers non-invasively, and that continuous glucose monitors are "the only commercial success." The sources do not make either claim. That sentence now quotes the program page, and the words "the only commercial success" were removed. (6) These numbers, names and dates are in neither source and were removed: "2–4 daily" fingersticks; "monthly" blood draws; Google/Verily and "abandoned in 2018"; Samsung; tear glucose "~10×" lower with a lag of "10–30 minutes"; enzyme sensors that degrade "within hours"; Schirmer strips and capillary tubes; tear volumes of "5–15 μL"; and "picomolar-to-nanomolar" concentrations. The sentences that held them were kept in a softer form without the figures. (7) The text said the program envisions a "punctal-plug-based platform" that "avoids the corneal surface, potentially solving the biocompatibility and vision-interference challenges of contact lens approaches." The sources say only that the system is inserted into the tear duct. They do not use the term punctal plug and do not compare the device with contact lenses. The text now says that the cited pages make no such comparison, and the two mentions of the punctal plug as ARPA-H's approach in the notes above now say tear duct. (8) A sentence was added to the section on earlier attempts giving what the sources do say: tear testing in the clinic is the standard of care for diagnosing dry eye disease, treatment changes need a full exam and lab processing of tears, and no existing technology samples tears continuously. Confirmed against the sources and left as written: the program's name; continuous and simultaneous monitoring of tear biomarkers; closed-loop drug delivery. NOT supported by either source and left in softened form, with no source checked for them: the description of continuous glucose monitors; the examples of diabetes, transplant and autoimmune monitoring; and the general account of why smart contact lenses for glucose have struggled (lower and lagging tear glucose, dilution by reflex tearing, sensor stability, power, small tear volumes); and the remark that a device in the tear duct sits away from the corneal surface and may avoid interfering with vision. The H1 and the short title make a broader claim than the sources do, since the sources speak only about tears; they were left unchanged because no number or fact in them could be shown wrong from the sources. Genes untouched.