A force-sensing microsurgical instrument that detects forces below human tactile sensation

Sarah Sunshine, Marcin Balicki, Xingchi He, Kevin Olds, Jin Kang, Peter Gehlbach, Russell Taylor, Iulian Iordachita, James T. Handa

Research output: Contribution to journalArticle


PURPOSE:: To test the sensitivity and reproducibility of a 25-gauge force-sensing micropick during microsurgical maneuvers that are below tactile sensation. METHODS:: Forces were measured during membrane peeling in a raw egg and the chick chorioallantoic membrane models (N = 12) of epiretinal membranes. Forces were also measured during posterior hyaloid detachment and creation of retinal tears during vitrectomy in live rabbits (n = 6). RESULTS:: With the raw egg model, 0.5 ± 0.4 mN of force was detected during membrane peeling. In the chorioallantoic membrane model, delaminating the upper membrane produced 2.8 ± 0.2 mN of force. While intentionally rupturing the lower membrane to simulate a retinal tear, 7.3 ± 0.5 mN (range, 5.1-9.2 mN; P < 0.001) of force was generated while peeling the upper membrane. During vitrectomy, the minimum force that detached the posterior hyaloid was 6.7 ± 1.1 mN, which was similar to the force of 6.4 ± 1.4 mN that caused a retinal tear. The rate of force generation, as indicated by the first derivative of force generation, was 3.4 ± 1.2 mN/second during posterior hyaloid detachment, compared with 7.7 ± 2.4 mN/second during the creation of a retinal tear (P = 0.04). CONCLUSION:: Force-sensing microsurgical instruments can detect forces below tactile sensation, and importantly, they can distinguish the forces generated during normal maneuvers from those that cause a surgical complication.

Original languageEnglish (US)
Pages (from-to)200-206
Number of pages7
Issue number1
StatePublished - Jan 1 2013

ASJC Scopus subject areas

  • Ophthalmology

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