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Corrective lens. A corrective lens is a transmissive optical device that is worn on the eye to improve visual perception. The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia. Glasses or "spectacles" are worn on the face a short distance in front of the eye.
Abbe number. In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of V indicating low dispersion. It is named after Ernst Abbe (1840–1905), the German physicist ...
Reactive arthritis. Rheumatoid arthritis. Ehlers-Danlos Syndrome. Sarcoidosis. Scleroderma. Systemic lupus erythematosus. Temporal arteritis. Relapsing polychondritis. Granulomatosis with polyangiitis 50-60% have ophthalmologic manifestations, which can be a presenting feature in a minority of patients.
Chromatic aberration. Focal length of lens varies with the color of light. In optics, chromatic aberration ( CA ), also called chromatic distortion, color aberration, color fringing, or purple fringing, is a failure of a lens to focus all colors to the same point. [ 1][ 2] It is caused by dispersion: the refractive index of the lens elements ...
Aberrations of the eye. The eye, like any other optical system, suffers from a number of specific optical aberrations. The optical quality of the eye is limited by optical aberrations, diffraction and scatter. [1] Correction of spherocylindrical refractive errors has been possible for nearly two centuries following Airy's development of methods ...
When an object is located close to the eye, the rays of light from this object no longer approach the eye parallel to each other. Consequently, the eye must increase its refractive power to bring those rays of light together on the retina. This is called accommodation, and is accomplished by the eye thickening the lens. [11]
Aphakia. Aphakia is the absence of the lens of the eye, due to surgical removal, such as in cataract surgery, a perforating wound or ulcer, or congenital anomaly. It causes a loss of ability to maintain focus ( accommodation ), high degree of farsightedness ( hyperopia ), [ 1] and a deep anterior chamber. Complications include detachment of the ...
Uveitis. Uveitis ( / ˌjuːvi.aɪtɪs /) is inflammation of the uvea, the pigmented layer of the eye between the inner retina and the outer fibrous layer composed of the sclera and cornea. [1] The uvea consists of the middle layer of pigmented vascular structures of the eye and includes the iris, ciliary body, and choroid.