| 摘要 |
<p>The retina is illuminated the sclerotic and observed through the lens. This gives even illumination across most of the image, but over-brightness at the edges. Correction is by selective masking of the image. The masking is pref. by moving blinds inwards from the sides of the field of observation to cover approximately the over-bright areas. A motor drive can be used, and the movements synchronised with those of a camera shutter. Illumination is pref. by two bundles of optical fibres. An existing ophthalmoscope with only a single light source can be adapted by switching the light alternately from one fibre bundle to the other. This, too, can be motorised and synchronised with the movements of the blinds and the camera shutter.</p> |
