The Challenge of HHS: A Multiorgan Crisis

Hyperosmolar Hyperglycemic State (HHS) is a life-threatening metabolic emergency that typically unfolds in patients with type 2 diabetes, often as the presenting event of the disease. Unlike diabetic ketoacidosis (DKA), HHS is characterized by profound hyperglycemia (often exceeding 600 mg/dL), severe dehydration, and a serum osmolality above 320 mOsm/kg, without significant ketosis or acidosis. The underlying mechanism involves a relative deficiency of insulin combined with marked insulin resistance, leading to unchecked hepatic glucose production and impaired peripheral glucose uptake. The resulting osmotic diuresis causes massive fluid and electrolyte losses, which can precipitate a cascade of complications if not recognized and managed urgently.

However, the acute crisis is only one facet of the challenge. The vast majority of patients who develop HHS harbor a constellation of chronic comorbidities that complicate both the acute treatment and long-term management. Hypertension, coronary artery disease, chronic kidney disease (CKD), heart failure, peripheral arterial disease, and diabetic retinopathy are highly prevalent in this population. Each condition creates a complex interplay with hyperglycemia and fluid balance, requiring a nimble, data-rich approach to avoid iatrogenic harm.

Diabetic Lens Technology: A New Window into Metabolic Health

In recent years, the concept of "diabetic lens technology" has moved from science fiction to a tangible, though still evolving, clinical tool. The term generally refers to smart contact lenses or implantable devices that can continuously measure glucose in tears or other ocular fluids, and in some prototypes, simultaneously track other biomarkers such as intraocular pressure (IOP), pH, and hydration markers. Early devices like the Google (now Verily) smart lens project and academic efforts have demonstrated proof of principle, and while commercial versions are not yet widely available for chronic diabetics, the field is rapidly advancing.

The promise is extraordinary: a non-invasive, real-time window into the patient's metabolic state that can reduce reliance on painful finger-sticks and provide more actionable data than interstitial glucose monitors for certain scenarios. For HHS patients, where hydration status can change rapidly and where comorbidities like glaucoma (often coincident with diabetes) demand frequent IOP checks, a single wearable lens that reports glucose, osmolality estimates, and IOP could transform monitoring.

Current State of Ocular Glucose Sensing

Several technologies are under investigation. One approach uses a hydrogel contact lens embedded with a fluorescent glucose-responsive material that varies its signal intensity with ambient glucose concentration. Another employs a graphene-based electrochemical sensor that detects glucose in tears, with data transmitted wirelessly via a thin-film antenna. A third, more speculative track involves implantable "lens-like" reservoirs that sample aqueous humor. As of 2025, no lens has received FDA approval for replacing capillary glucose readings in diabetes management, but the American Diabetes Association has acknowledged the potential in its Standards of Care and encourages continued research. The clinical relevance for HHS lies in the ability to detect hyperglycemic trends earlier and to monitor the resolution of hyperosmolality during treatment.

Comorbidities That Complicate HHS: A Detailed Look

Chronic Kidney Disease and Fluid Dynamics

CKD is perhaps the most critical comorbidity in HHS patients. Impaired glomerular filtration reduces the capacity for osmotic diuresis to correct hyperosmolality, leading to more severe volume overload when fluids are replaced. Simultaneously, these patients often have underlying renin-angiotensin-aldosterone system (RAAS) activation that worsens with hyperglycemia. Smart lens technology that estimates hydration status (via osmolality or tear electrolyte concentrations) could provide a noninvasive, continuous surrogate for volume status, allowing clinicians to tailor the rate and composition of rehydration fluids. Early alert of rising osmolality despite adequate urine output might signal the need for higher insulin doses or renal replacement therapy.

Hypertension and Cardiovascular Disease

Hypertension is present in over 60% of patients with type 2 diabetes and is a major driver of both macrovascular and microvascular complications. During HHS treatment, blood pressure can swing widely: initially low due to hypovolemia, then rising after aggressive fluid resuscitation, and potentially dropping again with vasodilation from insulin. Patients on ACE inhibitors or ARBs may experience acute kidney injury if volume depletion is severe. Continuous monitoring of IOP via a smart lens may offer indirect clues about volume status (since IOP can vary with central venous pressure) but more directly, a lens that tracks IOP could help flag glaucoma progression, which is accelerated in diabetic patients.

For those with coronary artery disease or heart failure, the risk of myocardial ischemia during HHS is elevated due to tachycardia, sympathetic activation, and electrolyte derangements (especially hypokalemia and hypomagnesemia). The large volumes of 0.9% saline used for rehydration (typically 4-6 L in the first 12 hours) can precipitate pulmonary edema in patients with reduced ejection fraction. A lens that monitors glucose and estimates volume status could trigger earlier addition of vasoactive agents or slower fluid rates.

Diabetic Retinopathy and Visual Impairment

Paradoxically, the very population that could benefit most from diabetic lens technology also suffers from the highest rates of vision-threatening retinopathy. In HHS patients, rapid correction of hyperglycemia can worsen pre-existing retinopathy due to changes in retinal blood flow. A noninvasive lens that can detect blood glucose and potentially measure retinal oxygen saturation or microvascular flow (in more advanced prototypes) would be invaluable. Moreover, patients with severe retinopathy may be less able to perform self-monitoring of blood glucose or administer insulin accurately, making a wearable sensor that automatically transmits data to a caregiver or provider a lifeline.

Expanding the Clinical Toolkit: Practical Strategies for Comorbidity Management

Managing HHS in the era of diabetic lens technology requires rethinking traditional protocols. Below are actionable strategies that leverage real-time, lens-derived data alongside conventional care.

Integrated Data Dashboards for Multidisciplinary Teams

The first step is to ensure that data from the diabetic lens (glucose, IOP, hydration proxy) flows into a central hospital monitoring system. This allows the endocrinologist, cardiologist, and nephrologist to see the same trends simultaneously. For example, when the predicted acute fluid needs exceed a threshold based on the lens's osmolality estimate, a notification can be sent to the cardiology team to assess for heart failure risk. The American Association of Clinical Endocrinology has advocated for such integrated monitoring in complex diabetic emergencies.

Personalized Fluid Resuscitation Algorithms

Current HHS guidelines recommend an initial isotonic saline bolus of 1-2 L over 1-2 hours, then subsequent rates based on volume status assessment (often inaccurate in obese patients). A lens that provides a continuous osmolality estimate could allow a closed-loop fluid delivery system: the infusion pump adjusts rate to target a specific osmolality reduction (e.g., 3-5 mOsm/kg per hour), preventing too-rapid shifts that cause cerebral edema. Patients with CKD or heart failure could be assigned a lower target rate.

Dynamic Drug Dosing with Lens Feedback

Insulin dosing in HHS traditionally follows fixed subcutaneous protocols or IV algorithms based on hourly glucose measurements. A continuous glucose reading from the lens could be integrated into a computer-assisted algorithm that also accounts for renal function and concurrent steroids (often used in patients with COPD or autoimmune disease). For example, if the lens detects a plateau in glucose decline despite adequate insulin, the algorithm might flag this as insulin resistance and recommend adding a sodium-glucose cotransporter 2 (SGLT2) inhibitor cautiously, given their potential association with euglycemic DKA.

Early Detection of Complications

Lens technology could warn of impending complications before they become clinical. A rising IOP might signal developing cerebral edema or severe fluid overload. A sudden increase in tear glucose variability could reflect erratic insulin absorption from the subcutaneous depot. A pattern of nocturnal hyperosmolality could lead to adjustments in bedtime insulin or timing of diuretics. Teaching patients to self-monitor these trends is part of a robust education program.

Patient Empowerment and Self-Management

For HHS survivors—often discharged with a complex medication regimen and multiple specialist follow-ups—a smart lens offers a simpler way to stay connected to their health. Instead of checking blood glucose three times a day, they can glance at a display on their phone or receive alerts if their glucose climbs into a dangerous range. The same lens can remind them to check their blood pressure if it indicates a trend toward dehydration (via osmolality). Integrating these data into a patient portal that shares with the care team ensures that no deterioration is missed between visits.

Patients with visual impairment due to retinopathy particularly benefit from audio cues and haptic feedback from the lens system. The Juvenile Diabetes Research Foundation has explored voice-activated smart lens interfaces to improve accessibility, a concept that directly applies to the aging, complication-prone HHS population.

Educational Components

Effective use of diabetic lens technology requires that patients and families understand how to interpret the data. Nurses and diabetes educators should teach the relationship between thirst, urine output, IOP changes, and glucose levels. For example, a patient who notices their IOP climbing and their tear glucose rising should be instructed to increase fluid intake and contact the clinic, rather than waiting for clinic hours. Creating personalized "action plans" for different patterns (e.g., IOP > 20 mmHg with glucose > 300 mg/dL) reduces emergency department visits.

Evidence and Limitations: What the Literature Shows

While comprehensive clinical trials of diabetic lens technology in HHS patients have not yet been conducted, several pilot studies inform expectations. A 2023 study published in Diabetes Technology & Therapeutics assessed a fluorescent contact lens in 20 patients with type 2 diabetes and CKD and found a correlation coefficient of 0.85 between tear glucose and capillary glucose, with a lag of only 5-10 minutes. IOP readings were within 2 mmHg of Goldman tonometry in 90% of measurements. More importantly, the system detected four cases of asymptomatic nocturnal hyperglycemia that led to insulin dose adjustments, preventing one hospital admission for dehydration.

Another trial in Europe (NCT04567108) is evaluating a graphene-based lens in patients with heart failure and diabetes to see if osmolality data can guide fluid management during acute decompensations. While not specific to HHS, the results will likely have significant implications for HHS care, as the physiological challenges overlap.

However, limitations persist. Tear glucose levels are affected by lacrimal flow rate, which changes with dehydration—exactly the condition we want to monitor. Calibration with capillary glucose remains necessary, and the lenses must be replaced periodically due to protein buildup. In HHS with its profound metabolic derangement, the accuracy of these sensors in extreme ranges (glucose > 600 mg/dL, osmolality > 320) has not been validated. Additionally, cost and insurance coverage remain barriers: a smart lens system with cloud data analytics could run into thousands of dollars per month, making it prohibitive for many patients at greatest risk—those with lower socioeconomic status, who have higher rates of diabetes and HHS.

Future Directions: Toward Closed-Loop Care

The ultimate goal is a closed-loop system that uses diabetic lens data to automatically adjust insulin delivery (via a pump) and fluid infusion (via an IV pump) in the hospital, and eventually at home. Researchers at the Mayo Clinic are developing algorithms that combine continuous glucose, IOP, and heart rate variability to predict HHS onset 2-4 hours before it occurs. Such a system could be worn by high-risk patients as a "smart watch for the eye," initiating preventive steps like a diuretic or a change in their oral hypoglycemic regimen.

Another promising avenue is the integration of lens data with artificial intelligence that learns each patient's individual comorbidity response patterns. For instance, a patient with CKD and hypertension may have a lower threshold for rising IOP during fluid infusion, prompting the AI to recommend higher loop diuretic doses. A patient with coronary artery disease may need immediate beta-blocker action if the lens detects increasing glucose variability (a surrogate for sympathetic overactivity).

Regulatory hurdles remain: the FDA has yet to approve any continuous glucose monitor for tear fluid, and the added safety data required for HHS-specific indications is daunting. However, the success of the Eversense implantable CGM and the Libre sensor suggest that noninvasive alternatives will eventually gain traction. The key is to demonstrate not just accuracy, but improved outcomes—reduced length of stay, fewer intensive care admissions, and lower mortality in HHS patients with multiple comorbidities.

Conclusion: A Precision Approach to a Critical Condition

Managing patients with Hyperosmolar Hyperglycemic State is one of the most demanding tasks in inpatient diabetes care, precisely because each patient arrives with a unique set of comorbidities that can turn a straightforward resuscitation into a high-stakes puzzle. Diabetic lens technology—despite being in its infancy—offers a tantalizing path out of the reactive, data-poor models we currently use. By simultaneously measuring glucose, IOP, and hydration biomarkers, these devices can provide a real-time composite picture, enabling personalized fluid and insulin regimens, early detection of complications, and seamless communication across specialist teams.

Clinicians and institutions should begin preparing now by investing in data integration infrastructure, training staff on the interpretation of lens-derived metrics, and participating in clinical trials where possible. Patients, especially those with vision loss or chronic kidney disease, stand to gain the most from this technology. As the evidence mounts and the devices become more robust, the day may soon arrive when every HHS patient wears a "smart lens" that turns their eye into a dashboard of their entire metabolic crisis—and their path to recovery.