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Spectacles (glasses) to correct refractive errors of the eye; not invasive Contact lenses: to correct refractive errors of the eye; a little invasive Phoropter: used in refraction testing Tonometers: used to determine the intraoccular pressure (IOP) - useful in glaucoma; video link for various types of tonometers. Speculum:
Optical glass refers to a quality of glass suitable for the manufacture of optical systems such as optical lenses, prisms or mirrors.Unlike window glass or crystal, whose formula is adapted to the desired aesthetic effect, optical glass contains additives designed to modify certain optical or mechanical properties of the glass: refractive index, dispersion, transmittance, thermal expansion and ...
Eyeglasses work as an added lens of the eye serving to bend the light to bring it to focus on the retina. Depending on the eyeglasses, they serve many functions. [37] Reading glasses These are general over-the-counter glasses which can be worn for easier reading, especially for defective vision due to aging called presbyopia.
Adjustable focus eyeglasses have one focal length, but it is variable without having to change where one is looking. Possible uses for such glasses are to provide inexpensive eyeglasses for people from low-income groups , developing countries , third world countries or to accommodate for presbyopia.
A photochromic eyeglass lens, part of the lens darkened after exposure to sunlight while the other part remained covered. A photochromic lens is an optical lens that darkens on exposure to light of sufficiently high frequency, most commonly ultraviolet (UV) radiation. In the absence of activating light, the lenses return to their clear state.
Comparison of an ideal image of a ring (1) and ones with only axial (2) and only transverse (3) chromatic aberration. There are two types of chromatic aberration: axial (longitudinal), and transverse (lateral). Axial aberration occurs when different wavelengths of light are focused at different distances from the lens (focus shift ...
A monochrome [1] or monochromatic image, object or palette is composed of one color (or values of one color). [2] Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog).
A case history using the X-Chrom lens for a rod monochromat is reported [60] and an X-Chrom manual is online. [61] Tinted glasses (e.g. Pilestone/Colorlite glasses) apply a tint (e.g. magenta) to incoming light that can distort colors in a way that makes some color tasks easier to complete.