Renowned Professor John Marshall, Frost Professor of Ophthalmology at the Institute of Ophthalmology, University College London, is celebrated for inventing the Excimer laser and revolutionising refractive disorder correction with over 70 million procedures worldwide. Co-founder of the first FDA-approved laser refractive surgery company, he pioneered the Diode laser for diabetic eye issues and developed the 2RT laser for dry AMD treatment. Marshall, with 500+ research papers and numerous awards, chairs medical advisory boards, led initiatives against laser weapon use, and plays key roles in industry, startups, and charitable organisations. His impactful career spans six decades, marked by innovations, honours, and global influence.