AI Insight
This study characterized the bioimpedance properties of six major ocular tissues (sclera, corneal epithelium, iris, lens, vitreous, and retina) across a frequency range of 5 kHz to 1 MHz using intact ex vivo porcine eyes under simulated surgical conditions. The results showed that each tissue type displays distinct, reproducible, frequency-dependent impedance signatures, with 60–80% of tissue pairs being statistically separable at tested frequencies. The strongest tissue differentiation was observed at 50–100 kHz, where median pairwise effect sizes reached Cohen's d ≈ 1.04–1.06, and ROC-based separability was highest at 5 kHz (AUC = 0.91).
Why it matters
These findings lay the groundwork for using bioimpedance sensing as a real-time tissue identification tool during ophthalmic microsurgery, potentially improving surgical precision and reducing the risk of inadvertent tissue damage. The established reference dataset could support the development of smart surgical instruments capable of distinguishing tissue types autonomously.
⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Purpose: To characterize the frequency-dependent bioimpedance properties of major ocular tissues in intact ex vivo porcine eyes under simulated surgical conditions and evaluate tissue separability at discrete frequencies. Methods: Bioimpedance spectra were acquired from sclera, corneal epithelium, iris, lens, vitreous, and retina in intact ex vivo porcine eyes using a two-electrode probe and a precision LCR meter over 5 kHz to 1 MHz. Measurements were obtained under balanced salt solution and ophthalmic viscosurgical device conditions. Probe-tissue contact was verified by microscope visualization and optical coherence tomography. Tissue separability at 5, 50, 100, and 900 kHz was evaluated using global and pairwise statistical comparisons, effect sizes, and ROC-based separability metrics. Robotic-stabilized and handheld measurements were also compared. Results: Ocular tissues demonstrated distinct, frequency-dependent impedance magnitude distributions. Across sampled frequencies, 60% to 80% of tissue pairs showed significant differences after multiplicity correction. Median pairwise effect sizes ranged from Cohen’s d = 0.48 at 5 kHz to 1.04 to 1.06 at 50 to 100 kHz. Median ROC-based separability was 0.91 at 5 kHz and 0.76 to 0.77 at 50 to 900 kHz. Robotic-stabilized measurements showed lower variance than handheld measurements, although tissue-specific impedance ranges and frequency-dependent trends were preserved across acquisition modes. Conclusions: Major ocular tissues exhibit reproducible, frequency-dependent bioimpedance signatures in intact ex vivo eyes under simulated surgical preparation. These findings establish a physiologically relevant ocular impedance reference dataset and support bioimpedance as a complementary modality for tissue differentiation in ophthalmic microsurgery.