Clinical Ophthalmology (May 2016)
Validation of sensor for postoperative positioning with intraocular gas
Abstract
Frank L Brodie,1 Kelly Y Woo,2 Ashwin Balakrishna,2 Hyuck Choo,2 Robert H Grubbs2 1Department of Ophthalmology, University of California San Francisco, San Francisco, 2Department of Medical Engineering, California Institute of Technology, Pasadena, CA, USA Purpose: Surgical repair of retinal attachment or macular hole frequently requires intraocular gas. This necessitates specific postoperative positioning to improve outcomes and avoid complications. However, patients struggle with correct positioning. We have developed a novel sensor to detect the position of the gas bubble in the eye and provide feedback to patients in real time. In this paper, we determine the specificity and sensitivity of our sensor in vitro using a model eye. Methods: We assessed the reliability of our sensor to detect when a gas bubble has deviated off a model retinal break in a model eye. Various bubble sizes representing the intraocular kinetics of sulfur hexafluoride gas and varying degrees of deviation from the correct position were tested using the sensor attached to a mannequin head with a model eye. Results: We recorded 36 data points. The sensor acted appropriately in 33 (91.7%) of them. The sensor triggered the alarm every time the bubble deviated off the break (n=15, sensitivity =100%). However, it triggered the alarm (falsely) 3/21 times when the bubble was correctly positioned over the retinal break (specificity =86%). Conclusion: Our device shows excellent sensitivity (100%) and specificity (86%) in detecting whether intraocular gas is tamponading a retinal break in a model eye. Keywords: postoperative positioning, intraocular gas, vitrectomy, retinal detachment, macular hole, pneumatic retinopexy
