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A pinhole occluder is an opaque disk with one or more small holes through it, used by ophthalmologists, orthoptists and optometrists to test visual acuity. The occluder is a simple way to focus light, as in a pinhole camera, temporarily removing the effects of refractive errors such as myopia. Because light passes only through the center of the ...
Pinhole glasses, also known as stenopeic glasses, are eyeglasses with a series of pinhole-sized perforations filling an opaque sheet of plastic in place of each lens. Similar to the workings of a pinhole camera , each perforation allows only a very narrow beam of light to enter the eye which reduces the size of the circle of confusion on the ...
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.
Pinhole see Pinhole occluder and Visual_acuity#Legal_definitions: PHNI Pinhole No Improvement see Pinhole occluder and Visual_acuity#Legal_definitions: PHVA Pinhole Visual Acuity: PL Perception of light POH / PrOH Previous ocular history PPA Peri-papillary atrophy Pt Patient RAPD Relative afferent pupillary defect OD Right eye (oculus dexter) Ret.
The abbreviation PH is followed by the visual acuity as measured with a pinhole occluder, which temporarily corrects for refractive errors such as myopia or astigmatism. PHNI means no improvement of visual acuity using a pinhole occluder. So, distant visual acuity of 6/10 and 6/8 with pinhole in the right eye will be: DscOD 6/10 PH 6/8.
Wide-field micrograph of a damaged 80 μm pinhole Natural pinholes formed by tree leaves – Solar eclipse of August 21, 2017 in Washington state. A pinhole is a small circular hole, as could be made with the point of a pin. In optics, pinholes with diameter between a few micrometers and a hundred micrometers are used as apertures in optical ...
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Folding set of Lorgnette spectacles, Bedford Museum, Bedford. Lorgnette used by David Scott Mitchell. A lorgnette (/ l ɔː ˈ n j ɛ t /) is a pair of spectacles with a handle, used to hold them in place, rather than fitting over the ears or nose.
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