Back of the eye mirror

Synonyms in a broader sense

Ophthalmoscopy, Retinal endoscopy, Funduscopy, Ophthalmoscopy English: ophthalmoscopy

Definition ophthalmoscopy

The ophthalmoscopy is the most frequently used examination method at the ophthalmologist. Here, a so-called ophthalmoscope is used to illuminate the rear area of the eye, i.e. the inner surface of the eye, which is not visible from the outside without the aid of an aid. This enables a precise assessment of the retina, vessels and the optic nerve head in particular, whose changes can quickly provide information about certain clinical pictures.

History

The direct ophthalmoscope was invented in 1850 by Hermann von Helmholtz (*1821) who studied in detail the processes of seeing and hearing. In his later life he also invented the ophthalmometer (an instrument for determining the curvature of the cornea). Two years later, monocular (i.e. performed with one eye) ophthalmoscopy was developed.

The further development to binocular (performed with two eyes) ophthalmoscopy took place much later, around the 1950s. Indirect ophthalmoscopy/back of the eye also allows the patient to fixate in the distance. In one hand, the doctor holds a light source, which can be either an ophthalmoscope or a simple flashlight, and uses it to illuminate the patient’s eye.

With the other hand, the doctor places a magnifying glass in front of the patient’s eye at a distance of approx. 13 cm with his arm outstretched, supporting himself best on the patient’s forehead to enable him to work more stably. The image now visible to him is, depending on the magnifying glass, magnified about 4 to 5 times, stands on its head and is laterally inverted, which is why this type of ocular fundus mirror requires considerably more practice to find one’s way around.

With this method, not so many details are visible, but it allows the observer a good overview of the retina. Indirect ophthalmoscopy is also possible binocularly, i.e. with two eyes of the physician, if the physician performs the examination with a slit lamp (an examination microscope) or a head ophthalmoscope. This improves the optical quality of the image he receives.

In a healthy eye, you will not see completely in the middle, but slightly shifted towards the nose, the exit of the optic nerve (papilla, blind spot). This is reddish to yellow, sharp-edged, round to longitudinally oval in shape and may have a central hollow. Here, the four branches of the vessels emerge from a central vessel, branching off upwards and downwards on both sides in an arc.

The arteries appear brighter and cross the darker veins. The veins should be approximately 3:2 thicker than the arteries. Further outwards is the yellow spot (macula lutea), which contains the point of sharpest vision, which normally shows a yellowish colour.