The International Orthoptic Association is deeply saddened to learn of the passing of Professor John Sloper on 19 October 2025, peacefully at home among his family.
Professor Sloper was a leading figure in the field of pediatric ophthalmology and strabismus, and a long-standing supporter of orthoptists worldwide. After earning his D.Phil. in neuroanatomy at the University of Oxford, he dedicated his career to understanding the neural mechanisms underlying binocular vision and amblyopia. His early work on the visual cortex of primates helped define how abnormal visual experience alters cortical connectivity, a foundation for decades of amblyopia research.
At Moorfields Eye Hospital in London, where he served as Consultant Ophthalmologist and later Honorary Consultant, he combined meticulous clinical practice with scientific inquiry. His studies using visual evoked potentials and psychophysics demonstrated fundamental differences between early- and late-onset strabismic amblyopia and revealed that both eyes, not only the amblyopic eye, undergo functional changes. He later extended this work to the role of binocular function and visuomotor coordination in children, helping to shape a more holistic understanding of visual development and recovery.
As President of the European Strabismological Association (ESA) from 2013 to 2023, Professor Sloper led with integrity and foresight, strengthening international collaboration, advancing education, and overseeing the establishment of the EBO subspecialty examination in Strabismus and Pediatric Ophthalmology. His calm authority, scientific curiosity, and generosity as a mentor inspired many within both the ophthalmology and orthoptic communities.
Professor Sloper will be remembered as an eminent scientist, respected clinician, and kind colleague whose contributions profoundly influenced how we understand and manage disorders of binocular vision.
Our thoughts are with his wife Myra, his children, and their families.
May he rest in peace.
International Orthoptic Association
