# A Review of Training and Guidance Systems in Medical Surgery
## 3 Methods
### Synthesis of the Selected Works
#### 3.8.5 Ophthalmology  
Ophthalmology simulators have been previously analyzed by the authors [42]. However, some of these training environments neither provide evaluation nor guidance modules. Cataract surgery involves replacing the cloudy lens inside the eye with an artificial one. As people grow, eye lenses start to become frosted, which disturbs the sight. [PERSON] investigated the feasibility of a virtual surgery simulator with evaluation capacities [81]. He programmed an application for phacoumulsification in cataract surgery. The solution consists of a monitor for visual orientation, and it uses a Geomagic Touch haptic device for interaction purposes. This application can be considered as a tool to monitor learning progress and assess skill competency. It collects data such as completion time of cross-shape trench creation, the number of tissues removed from the lens, the width and depth of the cut and the crossing angle, and the path of the phaco tip and the forces applied during sculpting to measure the operation.  
In a study carried out by [PERSON] et al., an extracapsular cataract extraction simulator was developed [82]. The authors developed an in-house pen-shaped haptic device. This device is used with a head-mount display model, the Aurora electromagnetic tracking device, a foot pedal, and a fake lens physical model to navigate a 3D virtual environment implemented using Unity. In the simulator, the user observes scenes through the head-mount display and control his/her view utilizing the foot pedal. The eye model was created using 3 DMax, and a 3D virtual model of a syringe with a bent tip needle was to interact with the virtual eye.  
On the other hand, [PERSON] et al. designed and developed a 2D environment for cataract surgery [83]. The Virtual Mentor Training Program software provides an interactive cognitive simulator for teaching hydro dissection. The software was used in seven academic departments of Ophthalmology in the Medical School of Harvard University. Decision-making and error recognition are features that a virtual mentor gives as feedback to students. Additionally, it provides help and references during the lesson. Pre-test, post-test, and satisfaction surveys were applied to students of the course. This data showed that residents enjoyed the experience and commented that this type of didactic resources encourage self-learning and could enhance performance on their education.  
Feasible training and assessment tools are also found in this area. The Eyesi surgical simulator manufactured by VRMagic is one of them. [PERSON] et al. used this simulator to measure the performance of trainees in intraocular operations [84]. A practice trial followed by three scored trials were performed. The time limit of each task was twenty minutes, which is considered normal in this type of surgery. Eyesi counts with a tracking system that captures the movement of the instruments and eye and the biomechanical reaction of the tissue. Eyesi provides users the ability to manipulate instrument settings, which lets them experience a real operation set-up. It has an instructor station that allows real-time performance monitoring. The system provides session recording and video playback to review the virtual process. Finally, Eyesi can also generate reports to evaluate individual performance data.  
Physical applications that allow guidance are described in researches as the one conducted by [PERSON] et al. [85]. In the system developed by these authors, a robot-assisted technique was applied in ophthalmic surgery. It consists of VFs to pivot around the remote center of motion (RCM), which is the incision point in this type of surgery. Five sub-micron precision piezo actuators provide VFs. The system's novelty is that VFs can be adjusted before or during the procedure, which enhances orientation and safety during surgeries. However, one of the points that should be considered in systems that use adjustability is that this action should be done automatically during the process to avoid the surgeon's distraction.