Charts & Drums Archives - Hospital Services Limited

LogMar Chart

admin_hsl — Tue, 15 Feb 2022 09:10:11 +0000

Wall mounted and floor mounted charts also available. Only available in ROI

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Human Eye Chart

admin_hsl — Tue, 15 Feb 2022 09:09:17 +0000

This chart covers the detailed anatomy of the human eye, including the structure of the retina, the anterior and posterior chambers and lacrimal apparatus. In addition, the visual and pupillary pathways, the muscles of the eye and their functions. Only available in ROI

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Eye Chart

admin_hsl — Tue, 15 Feb 2022 09:08:27 +0000

This chart is anatomically correct and covers most aspects/features of the human eyeball. 50 x 67 cm. Only available in ROI

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Catford Drum

admin_hsl — Tue, 15 Feb 2022 08:38:58 +0000

It has been problematical to decide how much a baby or young child can see; a subject for speculation for many years. In the young, where subjective results are unobtainable or unreliable, a method of objective examination must be used.

Optokinetic nystagmus was observed by Purkinge in 1825 and evaluated by Von Helmholtz in 1867. The eyes of a normal subject fix and follow the movement of an object to the periphery of the field and quickly jerk back to take up fixation on the next object.

It has been found that targets of decreasing size may be presented until they become too small to be fixed and nystagmus is no longer elicited. Use of this phenomenon is made with the present technique.

The apparatus consists of a hand held screen with a central aperture, a drum with targets consisting of a horizontal black line five minutes of arc thick offset by one minute placed around this aperture. The drum is rotated by a motor which oscillates the appropriate target across the aperture with a slow phase and quick return.

Only available in ROI

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