Abstract
Purpose :
This study proposes the application of micro-force sensing tools as a solution to the physical challenges associated with retinal microsurgery. A quantitative assessment of performance in participants of various skill levels is presented for free-hand and robotic use.
Methods :
We conducted retinal microsurgery simulations with a microforceps enabled to measure forces applied to both the instrument tip, and the point of contact between the sclera and the tool shaft. Five participants with increasing levels of surgical experience repeated standardized freehand movements (ten trials), by gently and accurately touching four points on the retina of an eye model. The experiment was repeated using a steady-hand eye robot with cooperative control. The force data was correlated with the distance of the tool to the retina, and the time spent by each participant to complete the experiment. We used generalized estimating equations to compare the differences among subjects
Results :
Tremor was damped by the stiff robot structure in all cases. The scleral forces were significantly higher in robot-assisted experiments (100.79 ± 32.81) as compared to free hand procedures (64.36 ± 26.58, p < 0.001) in all subjects. Higher tip forces were measured in procedures performed by participants with no prior experience in performing retinal surgery (4.32 ± 1.70) compared to free hand measurements (3.61 ± 1.74, p < 0.001). In addition, the tip force was inversely proportional to the degree of experience among surgeons (p < 0.001). Tool insertion position was maintained deeper (closer to the retina) for experienced surgeons (21.36 ± 1.01) as compared to the non-experienced group (20.68 ± 1.44, p = 0.001) in the free hand experiments. Procedure time was inversely correlated with tip force, shaft forces and depth of insertion.
Conclusions :
The robot stiffness eliminates tremor and attenuates contact sensation at the point of scleral entry. Increased tip forces are neutralized in experienced users. Experienced surgeons work closer to the retina and complete the task by performing shorter tip excursions. Surgical experience also correlates with procedures involving less applied forces and shorter overall times to task completion. These results support the concept of force-sensing tools as promising technology for the study and performance of retinal microsurgical procedures.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.