A phoropter contains different lenses used for refraction of the eye
... The working distance lens being one which has a focal length of the examiner's distance from the patient (e.g. +1.50 dioptre lens for a 67 cm working distance) ...
... The working distance lens being one which has a focal length of the examiner's distance from the patient (e.g. +1.50 dioptre lens for a 67 cm working distance) ...
Uses a magnetic field to bend beams of electrons
... Electron Microscope • Uses a magnetic field to bend beams of electrons; instead of using lenses to bend beams of light. ...
... Electron Microscope • Uses a magnetic field to bend beams of electrons; instead of using lenses to bend beams of light. ...
Medieval eyeglasses Originally intended to be for
... Originally intended to be for temporary wear, to correct permanently the focus of the eyes, spectacles, as they were then known, or eyeglasses, were invented sometime between 1280 A.D. and 1300 A.D. in Italy (they seem to have been invented independently, by two different persons, in a very short pe ...
... Originally intended to be for temporary wear, to correct permanently the focus of the eyes, spectacles, as they were then known, or eyeglasses, were invented sometime between 1280 A.D. and 1300 A.D. in Italy (they seem to have been invented independently, by two different persons, in a very short pe ...
eye healthcare - McCrystal Opticians
... cling film and therefore are very comfortable to wear. They are larger in diameter (approx 14mm) than their rigid counterparts (approx 9mm), covering all of the eyes cornea. This most popular type of lens can be worn on a daily, monthly or extended wear basis. ...
... cling film and therefore are very comfortable to wear. They are larger in diameter (approx 14mm) than their rigid counterparts (approx 9mm), covering all of the eyes cornea. This most popular type of lens can be worn on a daily, monthly or extended wear basis. ...
Corrective lens
A corrective lens is a lens worn in front of the eye, mainly used to treat myopia, hyperopia, astigmatism, and presbyopia. Glasses or ""spectacles"" are worn on the face a short distance in front of the eye. Contact lenses are worn directly on the surface of the eye. Intraocular lenses are surgically implanted most commonly after cataract removal, but recently for purely refractive purposes. Myopia (near-sightedness) requires a divergent lens, whereas hyperopia (far-sightedness) requires convergent lens.