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The complexity of spectacle lenses has increased enormously over the last three decades. The advent of aspheric lenses for the normal power range and the, now commonplace, progressive lenses for the correction of presbyopia, are just two examples of 21st Century technology. Freeform surfaces are now employed to personalize lenses to wearer’s needs and these may be both progressive and atoroidal in nature. At the same time, optometry has taken a sideways step from optics and physics into a more general primary health care profession with an ever-increasing amount of biological and medical content added to an already brimming curriculum, hence the need for persons without optometry training to undertake the study of spectacle lenses. Some years ago a post-graduate course was designed for opticians who had a good grasp of mathematics and the ability to pay close attention to detail in the lengthy trigonometric ray-tracing techniques employed in lens design calculations. The year-long course, is undertaken by distance learning, and has been undertaken via the internet by students from many countries around the world. Final assessment is by means of examination held by the Association of British Dispensing Opticians and takes the form of two three-hour papers, Paper One consisting of the determination of the aberrations of a spectacle lens by accurate trigonometric ray tracing and the second, a general paper on the optics of ophthalmic lenses. It leads to the professional qualification, ABDO (Hons) SLD.
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