Depending on the symptoms, eyesight, reaction, shape and symmetry of the pupils as well as the mobility of the eyes (and their muscles) can be examined.
Examination of eyesight
These include the examination of the visual acuity (visual acuity test), the visual field, ie the area that can be viewed in one direction when looking, as well as the color or dark vision.
- Visceral examination: They are almost a landmark of ophthalmologists - the boards with letters, numbers, hooks or pictures in different sizes. This can be used to determine short-sightedness or farsightedness as well as their extent.
- Visual field examination: Physicians and patients sit at the same height. Then the patient has to look in the direction of the doctor with both or with one of the eyes (and the other obscured) and determine the number of fingers held by him in different heights and directions or say when the finger is seen.
- Color vision: Color blindness and color vision deficiency can be recognized with the aid of certain panels on which colorful spots of color form patterns that are only recognized by people with color as a number.
Assessment of the pupil
The normal pupil narrows when exposed to light, even if it is not lit directly, but only the one on the other side. If this reflex does not work properly, it indicates certain diseases of the optic nerve, brain or paralysis of the ocular muscle. Pupil changes such as asymmetries, far or narrow positions can be caused by inflammation, medication or other pathological causes. The pupil is evaluated as part of the ophthalmoscopy (see below).
Assessment of eye mobility
The position of the eyes to each other, their mobility and the simultaneity of the movements are functions that are examined especially when squinting and seeing double images. First, the clinician assesses whether the light reflexes on the cornea are symmetrical, then makes a cover and reveal test for squint testing (covering one eye and checking how the other responds), and then has the patient look in nine different directions (using one) Fingers there).
In this important ophthalmological examination, the ophthalmoscope, which has a lighted magnifying glass, examines the different external and internal parts of the eye. If you suspect corneal injury, you can introduce fluorescent eye drops that accumulate at the site of injury and can be seen well with blue light. In order to be able to see the fundus, the optic nerve and the blood vessels particularly well, the eye is "dripped far", so the pupil is so much dilated with a certain drug that the doctor receives a particularly large "peephole",
If, for example, the previous tests can also be performed by an experienced general practitioner, the special examination techniques required for certain questions are reserved for the ophthalmologist. Below is a small selection:
- Slit lamp: With this special microscope, light can be introduced laterally into the eye and thus particularly good at assessing the cornea, iris and eye lens. If additional lenses and glasses are placed, the vitreous and retina are also clearly visible.
- Tonometry: If there is a suspicion of pressure increase in the eye, the exact intraocular pressure can be determined with this special device (tonometer), which is usually placed on the cornea under local anesthetic.
- Perimetry: This particular device helps to determine the field of view more accurately than the test described above. For this purpose, the patient gazes with one eye into the perimeter and indicates when he sees small, flashing lights in different places. These values are graphically implemented.
- Fluorescence angiography of the fundus: With this method, even the smallest changes in the vessel can be visualized. For this purpose, a dye is injected into the arm vein and made visible by blue light in the choroid and retinal vessels.
- Electrophysiological examinations: The function of the optic nerve, visual pathway and retina can be checked with the aid of small electrodes that measure the electrical activity.
- Imaging techniques: The ultrasound scan can be used to diagnose retinal detachments and vitreous detachments and to measure the longitudinal axis of the eye. The bony border of the eyeball (for example, after an accident) can be represented particularly well by computer tomography (CT), the soft tissues (for example, in suspected tumors), especially with the magnetic resonance imaging (MRI).