A sub-millimetric, 0.25 mN resolution fully integrated fiber-optic force-sensing tool for retinal microsurgery

Area of Science:

• Biomedical Engineering
• Ophthalmology
• Surgical Technology

Background:

• Retinal microsurgery demands high precision due to the delicate nature of eye tissues.
• Existing tools lack the sensitivity to detect subtle tool-tissue interactions crucial for preventing damage.
• Sclerotomy interactions complicate direct force measurement at the surgical tool tip.

Purpose of the Study:

• To design and analyze a force measurement device for microsurgical instruments.
• To enable sensing of forces directly at the tool tip within the sclera.
• To overcome challenges posed by tool shaft interactions with the sclerotomy.

Main Methods:

• Integration of 1-cm long, 160 micrometer diameter Fiber Bragg Grating (FBG) strain sensors into a 0.5 mm tool shaft.
• Development of an algorithm to compensate for environmental temperature fluctuations.
• Design and analysis of a distal force sensing prototype.

Main Results:

• The prototype achieved a force resolution of 0.25 milliNewtons (mN) in 2 degrees of freedom (DOF).
• The developed system demonstrated insensitivity to temperature variations.
• Successful distal force sensing interior to the sclera was achieved.

Conclusions:

• Sub-millinewton resolution force sensors are feasible for integration into microsurgical instruments.
• This technology has significant potential for enhancing both robotic and freehand retinal microsurgery.
• Improved force feedback can lead to safer and more precise surgical interventions.