keratoscope

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Related to Placido disc: retinoscopy, Placido disk

keratoscope

 [ker´ah-to-skōp″]
a device consisting of alternate black and white concentric circles and used for examining corneal curvature.

ker·a·to·scope

(ker'ă-tō-skōp'),
An instrument marked with lines or circles by means of which the corneal reflex can be observed.
[kerato- + G. skopeō, to examine]

ker·a·to·scope

(ker'ă-tō-skōp)
An instrument marked with lines or circles by means of which the corneal reflex can be observed.
Synonym(s): Placido da Costa disc.
[kerato- + G. skopeō, to examine]

keratoscope

An instrument from which bright concentric circles can be reflected by the CORNEA so as to reveal optical irregularities of the surface.

keratoscope

Instrument for examining the front surface of the cornea. It consists of a pattern of alternately black and white concentric rings reflected by the cornea and seen through a convex lens mounted in an aperture at the centre of the pattern. Such an instrument gives a qualitative evaluation of large corneal astigmatism, and is useful in cases of irregular astigmatism as in keratoconus, for example (Fig. K3). Syn. Placido disc. See corneal topography; photokeratoscopy; videokeratoscope.
Fig. K3 Keratoscopeenlarge picture
Fig. K3 Keratoscope
References in periodicals archive ?
The Sirius topography instrument is an anterior segment analysis system combining a monochromatic 360-degree rotating Scheimpflug camera with a 22-ring Placido disc. Twenty-five radial sections are acquired from the cornea and anterior chamber.
One of the most common methods is Placido disc imaging.
a) Blue filter for sodium fluorescein assessment of the tear film b) Placido disc filter for assessment of corneal shape c) A filter for assessment of tear osmolarity d) Grid filter for measurement of non-invasive tear break-up time (NIBUT)