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Strabismus surgery (also: extraocular muscle surgery, eye muscle surgery, or eye alignment surgery) is surgery on the extraocular muscles to correct strabismus, the misalignment of the eyes. [1] Strabismus surgery is a one-day procedure that is usually performed under general anesthesia most commonly by either a neuro- or pediatric ...
A wooden tripod holding an optical level is set up firmly on the ground. Levelling or leveling (American English; see spelling differences) is a branch of surveying, the object of which is to establish or verify or measure the height of specified points relative to a datum.
Isaac Newton (1643–1727) investigated the refraction of light, demonstrating that a prism could decompose white light into a spectrum of colours, and that a lens and a second prism could recompose the multicoloured spectrum into white light. He also showed that the coloured light does not change its properties by separating out a coloured ...
Principle of the periscope. The periscope on the left uses mirrors whereas the right uses prisms. a Mirrors b Prisms c Observer's eye Principle of the lens periscope. The two periscopes differ in the way they erect the image. The left one uses an erecting prism whereas the right uses an erecting lens and a second image plane. a Objective lens b ...
The unwanted interference effects are suppressed by vapour-depositing a special dielectric coating known as a phase-compensating coating on the roof surfaces of the roof prism. These phase-correction coating or P-coating on the roof surfaces was developed in 1988 by Adolf Weyrauch at Carl Zeiss [6] Other manufacturers followed soon, and since ...
The image formed on this ground glass can be observed directly, giving a waist-level reflex finder, or through a redressing optical device (set of mirrors or prism) for eye-level viewing, giving an eye-level reflex finder. With a reflex finder, a photographer may focus the image on the ground glass and frame the picture at the same time.
An occluder is placed over the eye that is not being tested (e.g.: over the left eye, to test the right eye's vision). A pinhole occluder is then placed before the patient's eye, and their vision is then tested again (each eye separately) to determine if the patient's poor visual acuity is a result of optical irregularities, or pathological issues.
Group of original deck prisms. A deck prism, or bullseye, is a prism inserted into the deck of a ship to provide light down below. [1] [2] [3]For centuries, sailing ships used deck prisms to provide a safe source of natural sunlight to illuminate areas below decks.