Promising High-Tech Devices in Dry Eye Disease Diagnosis

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TL;DR

This narrative review examines several high-tech diagnostic devices for dry eye disease (DED), including TearLab, IDRA, Keratograph 5M, and LipiView II. The main finding is that while these tools offer non-invasive, objective assessments, their reliability is limited and they cannot replace the comprehensive TFOS DEWS II diagnostic algorithm. The clinical significance is that these devices may aid in screening and monitoring, but clinicians should not rely on any single device for diagnosis.

Full summary

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**Background:** Dry eye disease (DED) is a common, multifactorial condition affecting 5–50% of the population, with symptoms ranging from minor discomfort to significant impairment of quality of life. The TFOS DEWS II diagnostic algorithm requires positive symptom questionnaires (DEQ-5 ≥6 or OSDI ≥13) plus at least one clinical sign (NIBUT <10 s, tear osmolarity >308 mOsm/L, inter-eye osmolarity difference >8 mOsm/L, or ocular surface damage). However, this algorithm is time-consuming and challenging in busy clinical settings. This narrative review evaluates several high-tech devices that aim to simplify and standardize DED diagnosis.

**Methods:** A literature review of articles published in the last 15 years on dry eye syndrome and innovative diagnostic devices was conducted using the National Library of Medicine, without language restrictions. The review focused on 11 devices: TearLab Osmolarity System, DEvice Hygrometer, IDRA, Tearcheck, Keratograph 5M, Cornea Dome Lens Imaging System, I-PEN Osmolarity System, LipiView II interferometer, LacryDiag Ocular Surface Analyzer, Tearscope-Plus, and Cobra HD Camera. Peer-reviewed randomized clinical trials, meta-analyses, systematic reviews, and observational studies were evaluated.

**Key Results:** - **TearLab Osmolarity System:** Measures tear osmolarity from a 50 nL sample. Szalai et al. found significant overlap between groups: mean osmolarity was 296.77 ± 16.48 mOsm/L in non-Sjögren dry eye (NSSDE), 303.36 ± 17.22 mOsm/L in Sjögren dry eye (SSDE), and 303.52 ± 12.92 mOsm/L in controls (p = 0.018), indicating poor discrimination. Szczesna-Iskander recommended at least three consecutive measurements for reliable values. - **IDRA Ocular Surface Analyzer:** Assesses NIBUT, tear meniscus height (TMH), lipid layer interferometry, blink quality, and meibography. A prospective study (75 patients) reported an AUC of 0.868 (95% CI: 0.809–0.927) for detecting DED. However, Lee et al. found IDRA had significantly lower meibomian gland dropout (45.36 ± 21.87) and higher partial blink rate (0.23 ± 0.27) compared to LipiView II (36.51 ± 17.53 and 0.51 ± 0.37, respectively). - **Keratograph 5M:** Measures NIBUT, meibography, bulbar redness, TMH, and lipid layer. Tian et al. (42 DED, 42 controls) found coefficient of variation ≤26.1% and ICC ≥0.75 for all measurements, with better reliability for NIKBUT than TMH in DED. However, Sutphin et al. concluded keratographic measures are not interchangeable with clinical tests, and Pérez-Bartolomé et al. found it overestimates ocular redness. - **I-PEN Osmolarity System:** Portable device measuring tear osmolarity via electrical impedance of palpebral conjunctiva. Shimazaki et al. found no significant difference between DED (871 eyes, 294.76 ± 16.39 mOsm/L) and non-DED (51 eyes, 297.76 ± 16.72 mOsm/L; p = 0.32). Alanazi et al. reported I-PEN values (294–336 mOsm/L in high-BMI group) were significantly higher than TearLab (278–309 mOsm/L), with poor accuracy. - **LipiView II Interferometer:** Measures lipid layer thickness (LLT) up to 100 nm and records blinking dynamics and meibography. Wong et al. found LVII had significantly lower meiboscores (1.43 ± 0.78) than Keratograph 5M (1.90 ± 0.81; p = 0.001) in 20 subjects. - **LacryDiag Ocular Surface Analyzer:** Assesses TMH, tear film interferometry, and NIBUT. Ward et al. (30 healthy subjects) found good relationship with Keratograph 5M but low intra-observer agreement (p = 0.0003 and p < 0.0001 for NIBUT). - **DEvice Hygrometer:** Measures tear film evaporation via relative humidity changes. A pilot study (8 patients: 2 DED, 6 healthy) showed higher RH in DED, but larger studies are needed. - **Tearscope-Plus:** Evaluates lipid layer patterns using Guillon’s classification. García-Resúa et al. noted significant correlation between experienced observers but potential misinterpretations. - **Cobra HD Camera:** Dedicated meibography module. Pult et al. (112 participants) reported mean MG loss of 30 ± 17% in asymptomatic and 45 ± 18% in symptomatic individuals. Iphra and Gantz found good inter-session repeatability and inter-examiner reproducibility.

**Clinical Implications:** Despite the promise of these devices for non-invasive, objective, and rapid assessment, the literature reveals inconsistent results, poor interchangeability, and limited reliability. No single device can replace the TFOS DEWS II algorithm. Clinicians should use these tools as adjuncts for screening and monitoring, but not as standalone diagnostic instruments. Further research with larger sample sizes and standardized protocols is needed to establish their clinical utility.