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Clinical Trial
. 2013 Jan 1;7(1):24-34.
doi: 10.1177/193229681300700104.

Blood glucose self-monitoring with a long-term subconjunctival glucose sensor

Achim Josef Müller  1 , Monika Knuth, Katharina Sibylle Nikolaus, Roland Krivánek, Frank Küster, Christoph Hasslacher, Gerd Uwe Auffarth
Affiliations
Clinical Trial

Blood glucose self-monitoring with a long-term subconjunctival glucose sensor

Achim Josef Müller et al. J Diabetes Sci Technol. .

Abstract

Background: To evaluate the feasibility of an implantable subconjunctival glucose monitoring system (SGMS) for long-term glucose monitoring, we investigated the in vivo performance of the system.

Method: The SGMS consists of an implantable ocular mini implant (OMI) and a handheld fluorescence photometer. A clinical study was performed on 47 diabetes patients split into two cohorts. Two different types of OMI were used, with and without a biocompatible surface coating. Duration of the study was 1 year. Correlation between capillary blood glucose and SGMS-derived interstitial fluid glucose was investigated during the first 6 months of the study.

Results: Both OMI types were tolerated well in the eyes of the patients. At the beginning of the study, the SGMS of both cohorts revealed a high accuracy with mean absolute relative difference (MARD) values of 7-12%. The performance of the uncoated OMIs deteriorated within 3 months of wearing time, exhibiting a MARD value of 20%. The performance of the surface-coated OMIs was preserved longer. Glucose correlation measurement with reasonable results (MARD of 14%) could be performed for up to 6 months of wear.

Conclusions: The biocompatible surface coating on the OMIs enabled a longer duration of action of up to 6 months compared with 3 months for uncoated implants in a clinical trial.

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Figures

Figure 1
Figure 1
Schematic view of the photometer. (A) Prototype photometer and ergonomically designed front shape as used in the clinical study. (B) Model of the final photometer to be marketed. The face support is formed like half a pair of eyeglasses.
Figure 2
Figure 2
Patient wearing an OMI. (A) The patient looks to the left; the OMI is visible as a light blue disk under the conjunctiva. (B) When the patient looks straight ahead, the OMI is not visible.
Figure 3
Figure 3
Consensus error grid analysis of cohort 1 (left) and cohort 2 (right) up to time points of 1 week, 1 month, 3 months, and 6 months (cumulative data).
Figure 4
Figure 4
Individual time courses of patients from cohort 1 (A) at 1 week and (B) 6 months of wearing time; and from cohort 2 (C) at 1 week and (D) 6 months of wearing time.
Figure 5
Figure 5
Comparison of in vitro physiological stability test data of a surface-coated OMI (cross signs) and in vitro measurements of the corresponding explanted OMI with (hollow triangle) and without (solid triangle) fibrous capsule after 1 year in vivo
Figure 6
Figure 6
Histopathological staining of OMIs in the surrounding fibrous capsule from (A,C) cohort 1 and (B,D) cohort 2.
See this image and copyright information in PMC

References

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