Development of an augmented virtual reality simulator for training ophthalmologists in phacoemulsification cataract surgery

Cataract is categorised as a common vision illness that is diagnosed in a large group of eye patients every year. The majority of such patients affected by this illness suffer from aging, diabetes or overexposure to ultraviolet radiation. Phacoemulsification cataract surgery is the surgical techniq...

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Bibliographic Details
Main Author: Lam, Chee Kiang
Format: Thesis
Language:English
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Online Access:http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/44124/1/p.1-24.pdf
http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/44124/2/full%20text.pdf
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Summary:Cataract is categorised as a common vision illness that is diagnosed in a large group of eye patients every year. The majority of such patients affected by this illness suffer from aging, diabetes or overexposure to ultraviolet radiation. Phacoemulsification cataract surgery is the surgical technique that has been currently used to remove the cataract from the patients' eye and restore their vision by implanting an artificial lens. The traditional master-apprentice teaching method has been commonly used in phacoemulsification cataract surgery training to transfer the surgical skills from a professional ophthalmologist to a medical practitioner. This teaching method includes wet-lab surgical training on animals and human cadavers. However, differences in the anatomy and mechanical properties between animals and humans may lead to lethal errors during a real surgical operation. In addition, experimentation on animals and humans in medical research, testing and education has been a controversial issue due to the ethical concerns in medical research. Existing simulators are somewhat incomplete and unable to provide virtual surgical training and supervision for the main procedures of phacoemulsification cataract surgery. An augmented virtual reality simulator, which is capable of providing a controlled virtual environment for medical trainees and ophthalmologists to conduct surgical training on virtual human subjects, is proposed to solve these constraints. The proposed simulator consists of a virtual surgical platform, which is formed by a haptic interface, graphical user interface (GUI), virtual surgical instruments and three dimensional (3D) eye models. The four main procedures of phacoemulsification cataract surgery, namely corneal incision, capsulorhexis, phacoemulsification, and intraocular lens (IOL) implantation, are simulated by using different types of topological modifications on the anatomy of the human eye. The proposed simulator is also capable of providing supervision to users via the graphical surgical guidance system without the presence of a human instructor and performance parameters are applied into the virtual surgical training system to increase the surgical awareness and skill of the medical trainees. A pair of Phantom® Omni haptic devices is used in the proposed simulator as a human-computer interface for users to manoeuvre the virtual surgical instruments in the 3D environment. The view and the 3D models of surgical tools and anatomy of eyeball can be selected and changed by using the interactive GUI. The four main procedures of phacoemulsification cataract surgery were successfully simulated at the minimum haptic feedback rate of 1 kHz and a graphical rendering rate of 30 frames per second. The graphical surgical guidance system, which is designed in the simulator, was able to react and respond interactively to the action and performance of the users throughout the procedures. The results indicate that medical trainees were able to improve their performance with the supervision that was provided by the guidance system. An experimental study on a set of performance parameters was conducted by a group of medical residents and ophthalmologists. The experimental results highlight the difference in actual surgical experience between ophthalmologists and medical trainees. The awareness and performance of the medical trainees progressively improved throughout the surgical training trails. The proposed simulator was compared with other existing simulators and the results indicate high plausibility in the virtual training of phacoemulsification cataract surgery.