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. 2014 Jul;28(7):880-7.
doi: 10.1038/eye.2014.99. Epub 2014 May 9.

Indentation and needle insertion properties of the human eye

A Matthews  1 , C Hutnik  2 , K Hill  3 , T Newson  4 , T Chan  5 , G Campbell  6
Affiliations

Indentation and needle insertion properties of the human eye

A Matthews et al. Eye (Lond). 2014 Jul.

Abstract

Purpose: Characterization of the biomechanical properties of the human eye has a number of potential utilities. One novel purpose is to provide the basis for development of suitable tissue-mimicking material. The purpose of this study was to determine the indentation and needle insertion characteristics on human eye globes and tissue strips.

Methods: An indenter assessed the elastic response of human eye globes and tissue strips under increasing compressive loads. Needle insertion determined the force (N) needed to penetrate various areas of the eye wall.

Results: The results demonstrated that globes underwent slightly greater indentation at the midline than at the central cornea, and corneal strips indented twofold more than scleral strips, although neither difference was significant (P=0.400 and P=0.100, respectively). Significant differences were observed among various areas of needle insertion (P<0.001). Needle insertion through the anterior sclera (adjacent to the limbus) and posterior sclera (adjacent to the optic nerve) required the greatest amount of force (0.954 and 1.005 N, respectively). The force required to penetrate the central cornea (0.518 N) was significantly lower than all other areas except the midline sclera (0.700 N) CONCLUSION: These data form the basis for further research into the development of a tissue-mimicking human eye construct with potential utility as a model for use in ophthalmology research and surgical teaching.

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Figures

Figure 1
Figure 1
(a) Indentation of a human eye globe at the midline sclera. (b) Needle insertion through the central cornea.
Figure 2
Figure 2
Typical indentation response of human eye globe at the midline sclera. The grey line indicates the line of best fit from which the slope was derived.
Figure 3
Figure 3
(a) Typical needle insertion curve through the posterior sclera of a human eye. (b) Mean force (N) required to penetrate various areas of the human eye. (c) Schematic illustration of needle insertion sites on a human cadaveric eye. A=central cornea (0.518 N), B=corneoscleral limbus (0.788 N), C=anterior sclera (0.954 N), D=midline sclera (0.7 N), E=posterior sclera (1.005 N).
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