# User Friendliness of a Wearable Visual Behavior Monitor for Cataract and Refractive Surgery
## 4 Discussion  
In today's world, visual acuity is not only becoming more and more important, but the demands on the visual system have increased significantly, whether at work or in leisure time. Various studies have shown that 61% of the patients prefer an explicit decision by the physician regarding the cataract surgery [21; 22]. This strong dependency and importance of the physician's decision-making must be compared to the importance of patient involvement in order to maintain high patient satisfaction [23; 24]. Previous studies show that the improving patients' perceived level of understanding is an important factor for the high level of patient satisfaction with the results of a cataract surgery [1; 25; 26; 27]. There is an increasing demand to understand patient needs and expectations when planning cataract and refractive surgeries. It is generally accepted that understanding patient behavior and expectations and including this information in the planning process results in better surgical outcomes. Psychometric tests in the form of cataract surgery outcome questionnaires have been developed, identifying the limitations of performing daily tasks due to an individual's vision, a trait known as visual functioning [15; 16]. The use of questionnaires and visual assessments in measuring patient outcomes is effective; however, the subjectivity of these methods is questionable. Nevertheless, questionnaires are very important in addition to objective measurement, because they reflect the important subjective part of the patient's feelings. Its importance and introduction have been used in the literature for a long time where specific questionnaires have been developed for specific questions [23], as we have used it in our study. Current psychometric measures may be subject to systematic error such as recall bias and could cause judgment errors resulting in patient discontent with surgical outcomes [19; 20]. Integrating technology, such as the wearable VBM, which collects objective visual behavior data for pre-operative patient assessments, has shown improvement in the current understanding of patient visual behavior. It was very gratifying to note that the application of the VBM was, in the vast majority of cases, problem-free. Thus, the VBM measuring device could be installed with reasonable effort and be reliably used by the patient. In this sense, the goal was achieved to design a VBM in a way that not only works reliably but is also easy to use. Most of the study patients stated that they had severe to very severe visual problems before the surgery. None of the patients who reported very great difficulties in their daily tasks reported troubles in attaching the clip to the spectacles frame or VBM to the clip. The results of the analysis of the patients' visual performance based on their responses to the questionnaire showed that the group that was not satisfied with the user-friendliness had, on average, a higher visual acuity and a lower LOCS score, with the exception of one question related to the presentation of the information on the screen. This effect of the higher reported usability problems of patients with better vision can be attributed to the higher demands of patients with clear natural lenses. The feedback from patients on the system handling was mostly related to the adaptation to a specific spectacle frame, the correct  
Figure 9: Post-operative Cat-Quest 9 results showing that surgical results met or exceeded patients’ expectations. alignment of the VBM and clip, and the strength of the magnetic attachment. This feedback has been considered in the development of the next generation of the system. The size of the clip has been adapted to make it easier to handle, and the shape of the clip and wearable has been redesigned to visually match each other to make the attachment more intuitive. The clip has a defined arrow shape that points forward to indicate the direction of attachment.