The investigators study aims to evaluate the utility of eye vergence, an eye-tracking measure, as an indicator of visuo-spatial attention in children aged 4-17 years and adults, using computer-based eye-tracking tasks. Eye vergence, a binocular movement crucial for depth perception, has recently been linked to attentional control and neurodevelopmental conditions (NDCs) like ADHD and ASD. The investigators will work with children and adults from the CAN and Beckenham clinical centres to explore the relationship between eye vergence and diagnostic categories, potentially identifying subgroups with specific or overlapping attentional differences. This research may aid in the early detection of attention deficits, informing targeted treatments. The investigators will compare neuropsychological and behavioural data from routine clinical sessions with neurophysiological data collected via eye-tracking in a large sample of children aged 7-17 and adults with ADHD and ASD. These clinical measures are well-validated. The study will assess the modulation of eye vergence, pupil size, and head movements across tasks that target different attentional processes, such as orienting, disengaging, inhibiting, and sustaining attention. These tasks will be adapted from both Braingaze's battery and other validated eye-tracking tasks. Additionally, the investigators will explore whether AI can enhance the accuracy of rating scales and questionnaires used to measure ADHD and ASD symptoms in children and adults. With consent, the investigators will use data from previously diagnosed patients collected during routine assessments at the CAN and Beckenham centres. The investigators will also test the accuracy of using a smartphone selfie camera as an eye tracker. In a subset of 50 children (25 clinical and 25 controls), the investigators will evaluate this technology for its ability to measure eye vergence and identify attentional differences. This study qualifies as basic science because it aims to explore fundamental mechanisms of eye vergence and its relationship with attention, rather than evaluating or marketing a medical device for diagnosis or treatment. The primary objective is to understand how eye vergence, as a neurophysiological measure, correlates with attentional processes in individuals with ADHD and ASD. Although the study utilizes an eye-tracking device, it does so as a research tool to collect data on visual and cognitive processes. The focus is on expanding the knowledge of cognitive function and attention regulation in neurodevelopmental conditions, not on testing or validating the device for clinical use. This distinction makes the study appropriate for review by the receiving REC as basic scientific research, rather than as a clinical trial of a medical device.