# User Friendliness of a Wearable Visual Behavior Monitor for Cataract and Refractive Surgery
## 2 Materials and Methods  
Patients presenting for cataract surgery or refractive lens exchange were randomly selected to take part in this feasibility study to evaluate the VBM. Patients who met the inclusion criteria were recruited consecutively for the study. Upon enrolment, patients completed a modified Cat-Quest 9 questionnaire. For German-speaking sites, the questionnaire was modified to improve readability in German. Patients were trained and fitted with the VBM and instructed to wear the device for at least 36 h. Patients then returned a week later to complete a questionnaire on the user friendliness of the device and schedule surgery. In our study, we used a modified CATQ-9 questionnaire, which refers to the patient's ability to perform certain tasks. The questionnaire consists of 9 questions, with each question being rated on a scale of 1-4--from 1 for \"no problems\" to 4 for \"very big problems.\" In general, it is asked whether the patient has problems with vision in everyday life and how satisfied the patient is with his or her vision. In particular, the questions ask how well the patient sees on the computer, how well he/she recognizes faces, how well he/she recognizes prices when shopping, how well he/she walks on uneven ground, how he/she watches television with subtitles, and what is his/her favorite gastime and hobbies. This covers a large part of daily life. The following inclusion criteria are applied: Age over 18 years old, participants considering IOL procedures, participants considering refractive laser procedures, and participants willing and able to participate. As exclusion criteria, we have defined the following points for the study: Unwillingness to participate, manifestation of macular disease based on OCT(Optical Coherence Tomography) /fundus photography, corneal scar or sign of corneal decompensation, standard surgery exclusion criteria, inability to make all postoperative visits, history or manifestation of other pre-existing ocular conditions and comorbidity (amblyopia, monophthalmia), other predisposing sight-threatening ocular conditions (uveitis, diabetic retinopathy, ARMD, macular dystrophy, retinal detachment, neuro-ophthalmic disease, abnormal pupils [deformation] and iris), history of corneal or retinal surgery, evidence of iris or choriorentinal neovascularization, history of anterior segment pathology (aniridia), any scar from corneal endothelium damage (chemical burn, herpetic keratitis, cornea guttata), any medical history contraindicative of standard cataract surgery including those taking medications known to potentially complicate cataract surgery (e.g., \(\alpha\)1a-selective alpha blocker), and participating in another clinical trial. The primary endpoint of the study is testing the design and usability of the wearable and the station. The Visual Behavior Monitor is a wearable device to continuously monitor visual behavior of the user. During the study, two functionally equivalent versions of the system were used, called Mark II and Mark III. The description below focuses on the latest system, Mark III. The VBM is fixed on the spectacles frame with help of an adapter. Multiple adapters are provided to patients to allow attachment on all spectacles used by the patient. Patients can easily move the device from the adapter on one spectacle to the adapter on another when changing spectacles. The VBM is configured to start and stop measurements automatically when attached and detached from the adapter, as well as when spectacles are taken off. After the VBM measurement was carried out, the respondent was asked the following questions: 1. Is it easy to attach the magnetic clip to the spectacles frames? 2. Is it easy is to attach the wearable to the magnetic clip? 3. Do you always feel comfortable using the wearable? 4. Is it easy to use the wearable? Regarding the station, the following questions were asked. 5. Is the connection between the station and the wearable always working? 6. Is the information provided on screen always clear to you?