What eye exams are available?An eye exam with an ophthalmologist usually follows a specific pattern: after talking about the nature and severity of the symptoms, an eye test is often done to check the visual acuity of each eye. Then the doctor examines the eyes from the outside, looks at them more closely with the help of a slit lamp and measures intraocular prere . Eye drops are given before some examinations to dilate the pupil for a certain period of time. This makes it easier to evaluate the back of the eye. Depending on existing medical conditions and pre-existing conditions, this procedure may vary and may be supplemented by additional tests.
The major components of the human eye
What belongs to a general eye examination? Information on $CMS_IF( ! tt_headline.isEmpty)$$CMS_VALUE(tt_headline.toText(false).convert2)$$CMS_END_IF$
Reasons for an ophthalmologic examination can be, for example, external injuries or sudden visual disturbances. With age, vision also deteriorates, which is why many people go to the ophthalmologist sooner or later.
A general eye examination includes a visual acuity test and a test of pupillary reaction. The pupil normally contracts reflexively when light falls on it.
The doctor first looks at the eye from the outside and checks whether the conjunctiva or eyelids are red and inflamed, for example. In case of pain, it is important to describe as precisely as possible where it hurts: on the surface, in depth, or only when you move your eyes? Eye pain may also radiate toward the forehead or temple.
What happens when visual acuity is determined? Information about $CMS_IF( ! tt_headline.isEmpty)$$CMS_VALUE(tt_headline.toText(false).convert2)$$CMS_END_IF$
Those who are not sure whether their own visual performance has deteriorated can have their visual acuity (Visus) checked by an ophthalmologist. For this eye test, one eye is covered and the other eye is used to look at so-called vision test panels or a projection with letters, numbers or C-shaped characters in decreasing size.
Different types of eye charts
The visual acuity is shown by which signs can still be recognized from five meters away. In addition, the ophthalmologist tests the visual acuity at reading distance with reading charts from approximately 30 centimeters. Subsequently, the eye test can be repeated with corrective lenses if necessary.
Technically, visual acuity is a measure of perceiving two points separately. This becomes more difficult the closer these points are together.
How else is the eyesight tested? Information about $CMS_IF( ! tt_headline.isEmpty)$$CMS_VALUE(tt_headline.toText(false).convert2)$$CMS_END_IF$
Further examinations often follow to assess vision. This includes Color vision tests, in which certain patterns are to be recognized on colored color panels. Also the Eye mobility and the position of the eye to each other are important, the latter is, for example, altered in childhood strabismus due to different ocular refraction on the right and left side. Also the examination of the so-called Visual field belongs to it.
What is a visual field test? Information about $CMS_IF( ! tt_headline.isEmpty)$$CMS_VALUE(tt_headline.toText(false).convert2)$$CMS_END_IF$
What a person sees without moving the eye is called the visual field. For the examination a perimeter is used – a device that represents half of a hollow sphere. For the examination the head is slightly supported in a holder. A point fixed in the center of the hollow globe. The device emits light stimuli that move or become brighter and brighter. When you notice the light or a change, you press a key. The more points in the visual field are tested, the more accurate the diagnosis – but the examination takes correspondingly longer.
Perimetry examination: each detected light point is confirmed with a click
The visual field is very important to orientate in space. Since various diseases lead to visual field disorders, perimetry is often used when damage to the retina or optic nerve is suspected, but also in cases of unclear headaches or dizziness. Eye diseases such as glaucoma or age-related macular degeneration also lead to changes in the field of vision. The examination is painless, but can be exhausting, as you have to concentrate for a long time.
What is a slit lamp examination? Information about $CMS_IF( ! tt_headline.isEmpty)$$CMS_VALUE(tt_headline.toText(false).convert2)$$CMS_END_IF$
A slit lamp is an examination microscope that emits a narrow, slit-shaped light. It is one of the most important examination devices in ophthalmology. In this examination, the chin is also placed on a support, and the doctor sits opposite and illuminates one eye at a time.
Due to the sharply limited light beam and different types of exposure (direct, lateral, broadly scattered), it is possible to view almost all sections of the eye at up to 60x magnification: the anterior, middle and posterior eye up to the retina in the back of the eye. Modern slit lamps also contain a device for measuring intraocular prere.
What happens during an ophthalmoscopy? Information about $CMS_IF( ! tt_headline.isEmpty)$$CMS_VALUE(tt_headline.toText(false).convert2)$$CMS_END_IF$
With an ophthalmoscope, it is possible to look through the pupil to the back of the eye and examine the retina , optic nerve, blood vessels and choroid. The examination is also called ophthalmoscopy or funduscopy (fundus, Latin: background). About 20 minutes before the ophthalmoscopy, the pupils are dilated with special eye drops.
In direct ophthalmoscopy, the physician brings the device close to the eye, shines the light directly into it, and sees a small section of the back of the eye in high magnification. This is a particularly good way of assessing the center of the back of the eye with the optic nerve, the entrance of the blood vessels and the yellow spot. In indirect reflection, a magnifying glass with a light source is used. Examined from a distance of about 60 centimeters. The doctor sees a larger section of the eye's fundus. This allows a better overview. Also a three-dimensional view. The examination can also be combined with a slit lamp, in which case the retinal image is greatly magnified and better illuminated.
This examination can be used, for example, to detect retinal detachment or damage to the optic nerve. In the case of diabetes or high blood prere, the examination of the back of the eye can also be useful, since both diseases can damage the fine blood vessels of the eye.
The dilatation of the pupils leads to a strong sensitivity to light and also to blurred vision. The patient is therefore not allowed to drive or operate machinery until the effect of the eye drops has worn off.
How does the measurement of intraocular prere work?? Information about $CMS_IF( ! tt_headline.isEmpty)$$CMS_VALUE(tt_headline.toText(false).convert2)$$CMS_END_IF$
Measurement of intraocular prere (tonometry) is one of the most common examinations in ophthalmology. The increased prere occurs when the aqueous humor formed in the eye cannot drain off normally and accumulates. Normal intraocular prere in adults is considered to be between 10 and 21 mmHg (millimeters of mercury).
There are different devices for prere measurement. In so-called applanation tonometry, the cornea is first anesthetized with eye drops. Then a small measuring body is placed on the cornea, which exerts a slight prere on the eye.
The prere required to flatten the cornea over an area of three millimeters is measured. This corresponds to the value prevailing inside the eye.
Another way to measure intraocular prere is the so-called non-contact tonometry. The prere is measured with a short puff of air on the cornea. Both examinations are not stressful and not painful.
Further eye examinations Information on $CMS_IF( ! tt_headline.isEmpty)$$CMS_VALUE(tt_headline.toText(false).convert2)$$CMS_END_IF$
For certain diseases, further examinations can confirm the diagnosis and help to plan treatment. With the so-called Fluorescence angiography the retina is injected with a dye solution into the arm vein. The dye is distributed in all vessels, including those of the retina . Using a special camera, the doctor can then assess vascular changes in the eye.
Another examination is the so-called optical coherence tomography (OCT). This uses a laser light to measure retinal thickness, among other things. Fluid accumulations in the area of the retina can also be detected in this way.
Andreae S, Avelini P, Berg M, Blank I, Burk A. Encyclopedia of diseases and examinations. Stuttgart: Thieme; 2008.
Dahlmann C, Patzelt J. Basics Ophthalmology. Munich: Urban. Fischer; 2014.
Pschyrembel. Clinical dictionary. Berlin: De Gruyter; 2017.