Use this URL to cite or link to this record in EThOS:
Title: The assessment of visual behaviour and depth perception in surgery
Author: Nicolaou, Marios
ISNI:       0000 0004 2674 6994
Awarding Body: Imperial College London (University of London)
Current Institution: Imperial College London
Date of Award: 2007
Availability of Full Text:
Access from EThOS:
Access from Institution:
The purpose of this thesis is to identify new methods of improving the delivery and assessment of minimally invasive surgery (MIS), particularly under the constraint of monoscopic MIS visualisation. In this thesis, the role of visual spatial ability in the acquisition of surgical skills is first investigated. A psychometric test is used to elucidate the correlation between spatial ability and complex tasks, and highlight the need for more quantitative assessment of visuomotor behaviours in laparoscopic procedures. To this end, a wavelet-based analysis framework for instrument trajectory analysis is developed for extracting intrinsic motion behaviours. This is used to provide an insight into subconscious integration of the visual and motor axes in a depthless operative field. The issue of monoscopic visualisation of the operative field in MIS is also addressed and a method of improving depth perception by digitally enhancing a "weak" shadow cast by a secondary light source is proposed. By performing experiments on MIS novices, significant improvements in depth perception by the use of the proposed technique are demonstrated. Finally, eye tracking is used to study the difference in visual behaviour between laparoscopic novices and experts. A distinct visual behaviour of instrument tool-tip tracking during instrument manoeuvring is observed among the novices but not the experts, and this behaviour is shown to be repeatable in both groups. These results provide an important insight into how the cognitive, motor and visual stimuli are integrated during MIS surgery, as well as how the surgeons compensate for the depthless operative field. These findings can be used for the development of more focussed training curricula and the development of improved MIS instruments for its safe practice.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available