Complementary Visual Assessment: Validation of a High-Precision Eye-Tracking Kinetic Perimetry in the Evaluation of Visual Field Deficits in Hemianopia.

Vision is a multicomponential system where different aspects of visual processing rely on distinct neural circuits. This fundamental characteristic has profound implications for how we assess visual field defects. Classical gold standard perimetry focuses primarily on contrast detection. However, the size of the scotoma could be different when measured with kinetic perimetry since motion detection relies on different neural networks. Therefore, we developed and validated a high-precision eye-tracking kinetic perimetry as a complementary tool for evaluating visual field deficits in hemianopia. We emphasized methodological transparency and precise measurement of the transition zone between sighted and blind areas. Thirty-seven participants (17 with retrochiasmal lesions and 20 healthy controls) underwent test-retest evaluation using a kinetic perimetry system integrated with a Tobii Pro Spectrum eye tracker (0.03° RMS precision, 0.3° accuracy, 600 Hz sampling rate). Results demonstrated excellent test-retest reliability with adjusted ICC values exceeding 0.90 across all conditions. The application of an algorithm (LOESS) for noise reduction further improved measurement stability, with ICC increasing to 0.996 for controls and 0.988 for patients, while reducing standard deviation of errors from 4.69° to 1.52° in the affected visual field of patients. Based on these findings, we propose that a visual field enlargement exceeding 5° can be considered a meaningful change beyond the measurement variability of our perimetry. By embracing methodological transparency, including detailed disclosure of eye-tracking specifications and error measurements, and recognizing the multicomponential nature of vision, we aim to contribute to the understanding of visual field defects and their potential for recovery.