The Light Sensitivity Epidemic in Modern India: Convergent Epidemiological, Photobiological, and Environmental Factors Driving Photic Discomfort in the World's Most Populous Nation

India faces a convergent light sensitivity epidemic driven by five simultaneous factors: (1) 1.1 trillion annual smartphone-hours with 450-490 nm spectral peaks (EY 2024), (2) rapid LED lighting transition with unregulated spectral profiles, (3) 213 million migraine cases with 80-90% photophobia prevalence (GBD 2019), (4) 25.7% insomnia prevalence (medRxiv meta-analysis 2023), and (5) 50%+ population exposure to light-polluted skies. This narrative review synthesises epidemiological, photobiological, and environmental data to characterise the scope and mechanisms of India's light sensitivity burden. We evaluate limitations of current optical interventions (generic blue-light coatings, dark sunglasses) and present a three-tier wavelength-selective optical intervention framework: FL-41 dual-band filtration (NeuroCalm FLX+, Patent IN 202521094370) for migraine photophobia, amber filtration (Circadian560, Patent Pending IN 202521120977) for circadian disruption, and HEV-selective filtration (DayActive) for daytime screen comfort. 6 pages, 4 tables, 25 peer-reviewed references. Authors: Dubey S, Choudhary MAffiliation: Sleepaxa Private Limited, Mumbai, IndiaDPIIT Recognised | CTRI Registered | Wikidata: Q138837663 | ORCID: 0009-0003-7510-9254