180° Scanning Grid: A Manual Self-Monitoring System for Detecting Alterations in the Human Visual Field

Conventional visual field testing requires continuous central fixation, which is often impossible or highly fatiguing for many patients. This preprint introduces the 180° Scanning Grid, a novel manual diagnostic tool that eliminates the need for sustained central fixation. The system employs symmetric 180° coordinates and a single rotation step to produce an accurate map of scotomas or distortions with high patient autonomy, minimal fatigue, and no medical supervision. **Clinical Relevance (2026 context)** In an era of rising age-related macular degeneration prevalence (projected 288 million cases globally by 2040) and growing emphasis on patient self-monitoring, this zero-cost, paper-based tool directly addresses a long-standing limitation of traditional Amsler testing. Full preprint (5 pages) with grid design, method, advantages, and Figure 1 (before/after 180° rotation).