ABSTRACT
Different methods of correction of refractive errors with glasses were discussed in the paper. The problem of the use of antireflection coating and tinting or color coating of the lenses was also presented.
Subject(s)
Computer Terminals , Eyeglasses , Refractive Errors/rehabilitation , Equipment Design , HumansABSTRACT
Three variants of a new anomaloscope principle are described. This principle is distinguished by the fact that for generation of the mixed color and the reference color three interference filters with narrow band widths are used instead of an expensive dispersion prism. In the first variant the brightness of the mixed color field and the reference field is determined by three detectors (silicon diodes) and kept constant taking the relative spectral response into consideration. The degree of anomalous color vision present is indicated digitally by a microprocessor whose interface also permits data processing equipment to be connected. The second variant uses only one detector which sequentially pulses the three light sources and distributes the results to different signal channels for further processing. In the third variant, measurement is performed in the same way as in the second variant but with only one light source. Fiber optic bundles illuminate of the mixed color and reference fields and also permit adaptation of the eye to neutral. In this case additional optical attenuators are required to keep the luminance of the fields constant. An advantage shared by all three variants is that they have virtually no moving parts, employing monochromatic filters and cemented prism blocks with high-quality electronics. This has made it possible to produce a compact, rugged and efficient new-generation anomaloscope, which renders the considerable calibration and maintenance work previously necessary superfluous.
Subject(s)
Color Perception Tests/instrumentation , Color Vision Defects/diagnosis , Computers , Microcomputers , Color Perception , Humans , Visual FieldsABSTRACT
The principle of construction of a keratometer is explained which shows digitally the radii of curvature of the cornea obtained by automatic optical measurement and processed by an inbuilt computer.
Subject(s)
Cornea/anatomy & histology , Computers , Contact Lenses , Eyeglasses , Humans , Methods , Optics and Photonics/instrumentation , Photography/instrumentationABSTRACT
Description of the new Polaroid positive/negative film type 105. This film produces within 30 seconds a brilliant positive and a negative for high quality prints. The new camera-back 405 for the use of 8.5 x 10.5 cm Polaroid packfilms fits to any 4 x 5 inch cameras with international back.
