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More recent equipment in the museum tends to be big. Sometimes we can only collect part of it, as in this instance. The object is a computerised videokeratoscope / topographer with laser aperture and would have come originally with an attached computer to enhance its images for easier and more accurate diagnoses. You could use it to collect information about the shape of the cornea and its refractive characteristics. Pictorial records of patient examinations could be stored in the optional Bernoulli drive that was considered to have a huge capacity of 90MB. Made by Computed Anatomy Inc around 1989-1993 the TMS-1 was the first of a popular international range and its mapping function was based on the Corneal Modelling System (CMS) pioneered at the New York Eye and Ear Infirmary. Even though computer technology has allowed keratoscopy to become more widely accepted and more clinically friendly, the basic principles underlying the new technology are the same as those articulated by Gullstrand a century before. The example illustrated is a late model of its type and you're looking at the part the operator would have used. The integral monitor was for checking the alignment of the instrument with the patient's eye whilst the patient attempted to fixate on a blinking white light. A cone reflected 25 concentric rings on to the surface of the eye where curvature measurements would be taken automatically. The cone could be replaced with one containing 31 rings for the purpose of precise fitting of RGP contact lenses. This particular device was used by a Harley Street ophthalmic surgeon. It is to be hoped that his consulting rooms were spacious since practitioners were advised to place the unit well away from other instruments to avoid distractions during an examination. A low power laser beam was used to position the patient's corneal axis. For safety's sake the instrument had an automatic cut-out after sixty seconds but it was reckoned that normal examination should require no more than fifteen seconds.
Learn more about the history of RGP contact lenses.