Phoropter — an ophthalmic measuring device
The modern medical industry has a very large number of various technological devices in its arsenal – for example, a phoropter. Their main task is to facilitate the work of doctors, as well as to achieve the most accurate and best results in treatment, correction of ametropias, and solving accommodation problems for each patient. It is worth noting that the above-mentioned device is a special apparatus that replaces the inconvenient case with various trial lenses.
Phoropter somewhat resembles a large helmet placed at the patient's eye level. It comes with a sign projector that projects optotypes onto the wall. The examination itself proceeds in exactly the same way as when using trial frames, the only difference being that the device itself will change the trial lenses. Its use is simply indispensable when determining addition, selecting progressive lenses, and so on.
Simply put, it is a device for correctly selecting glasses. It allows measuring refractive errors, phorias, vertical and horizontal vergence, amplitudes of accommodation, and so on. The use of such a complex but important device significantly speeds up the examination process. At the same time, the possibility of errors is completely eliminated.
This device is used as a set of trial lenses during an objective check of visual acuity. The device itself is mounted on a special bracket at the ophthalmologist's workstation and is located directly in front of the patient. Inside the device there are disks with trial lenses that can be replaced using a control panel. Thus, an analogue of corrective glasses with absolutely any characteristics within the range is assembled.
Such a high-quality device from DongYang is usually used by ophthalmologists and optometrists to examine eyes, measure refractive error, and determine a prescription for glasses. The patient sits in front of the device and looks through it at a special chart located at optical infinity (six meters), then near (40 centimeters) if he needs reading glasses. After that, lenses and some settings are changed, and the patient's reaction to the adjustments is clarified.
Sometimes, to determine the initial settings, an autorefractor or retinoscope may be used. The main components of the device: cylindrical, minus and plus lenses, Risley prisms for measuring vergence and phorias, Jackson cross cylinder used for correction of astigmatism.
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