optical appliance

(redirected from optical aid)

appliance, optical 

Any optical system which is used in conjunction with the eye. Optical appliances include spectacles, contact lenses to correct sight and/or anomalies of binocular vision and also telescopes or microscopes to magnify an object. Syn. optical aid. See optical dispensing; ptosis.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
According to the centre, the crescent can be seen using optical aid on August 30 in select countries in North and South America, whereas it can be seen with the naked eye in most countries in the world on August 31.
The crescent is expected to be seen by optical aid only from the areas located under blue and magenta colour.
Diamonds is sprinkled with the perspective and history of the indigenous peoples of the region, beginning with a naked-eye primer on what is visible without optical aid from the country's national parks.
Binoculars can be a very helpful optical aid when observing at home.
Do not use optical aid like telescopes or binoculars - you will be blinded before you can even blink.
If the specimen being inspected is located a distance from the magnifier equal to its focal length, and 550nm light is again used for observation, equation (9) reveals this optical aid's diffraction-limited resolution to be about 1.1[micro]m.
Lyra's other two stars near Vega are also double: Zeta ([zeta]) Lyrae, difficult to split in binoculars but easy in a telescope, and colorful Delta ([delta]) Lyrae, wide and easy with any optical aid at all.
Twist-up eyecups, an oversized center-focus wheel with integrated adjustable diopter for instant focus capabilities, a padded aircell neck strap and a padded case with shoulder strap complete this precision elk-locating optical aid.
Be careful though, don't look at the sun directly with or without optical aid as permanent eye damage may result, wait until the sun has completely disappeared.
In other words, in terms of brightness the star and the planet would have appeared as a single, very faint star almost at the threshold of visibility without optical aid.