Most perceptions reach our brain through the eye – conversely, we send messages to our environment through the eyes. Whether we are sad, happy, afraid or angry: Our eyes communicate this to the other person. In half of all people, there is statistically a limitation of vision – in addition, many diseases such as diabetes, high blood pressure or migraine also affect the eyes.
Structure and function
The eye is often compared to a camera and this comparison is also very helpful for understanding structure and function. From the outside, the first thing you see in the eye is the iris, which has a different color in each person. Newborns often have blue eyes and the eye color still changes in the first 12 months. Light passes through the iris into the interior of the eye, where it hits the eye lens. The lens contracts on its own or is pulled apart by a fine apparatus, depending on whether we are looking far or near. In this way, it transmits a sharp image to the retina, which lines the inside of the eyeball. “Seeing” on the retina is done by two different types of sensory cells called photoreceptors: cones and rods. Cones see in color, rods in black and white. The retina does not have the same number of rods and cones everywhere. There is one area of sharpest vision (the yellow spot, the macula) with many cones and surrounding areas where vision is blurred. In one place, the blind spot, you see nothing at all, there the optic nerve (optic nerve) pulls in the direction of the brain, where then the sensory impressions are processed further.
Eye complaints
Eye discomfort can occur on the outside of the eye or inside. Common external complaints include itching or burning, a watery, red, or dry eye, or the sensation that a foreign object is stuck between the eyelid and the conjunctiva or cornea. Other, “internal” complaints include visual disturbances ranging from double vision to vision loss, pain, a pressure inside the eye, or the feeling of having wandering debris in the eye.
Examination Methods
There are many different methods to detect eye complications:
- Medical history
- Inspection and palpation
- Smear
- Ophthalmoscopy
- Visual acuity and visual field testing
- Electrophysiological examinations
- X-ray, ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI).
In the following, you will be introduced to these examination methods in more detail.
1. anamnesis: inquire about medical history.
All complaints can be further narrowed down by asking specific questions. For example, a watery eye may itch and burn at the same time, or the complaints may occur only seasonally (for example, in a pollen allergy). Visual disturbances can occur together with other diseases, for example, photophobia and optical hallucinations have been described in migraine – and a small “stroke” in the eye can be a first warning sign of an impending cerebral infarction. These distinctions show the doctor which clinical picture is behind the complaints.
2. Inspection and palpation: looking at and palpating.
In conjunctivitis, the conjunctiva is often visibly red and the eye is very watery. A skilled doctor can use a spatula to flip the upper eyelid, revealing a foreign body or change under the lid. A misalignment of the eye is checked by asking the patient to follow the examiner’s finger with both eyes. This can reveal a squinting posture. A hematoma, increased intraocular pressure due to too much aqueous humor or – fortunately rarely – tumors lead to an eyeball under tension, which is particularly noticeable in a side-by-side comparison.
3. smear with a swab
If an infection of the outer layers of the eye is suspected, a swab is used to collect some eye fluid, which is then examined for germs in the laboratory.
4th ophthalmoscopy for deep insights.
An ophthalmoscope is used to look through the lens at the retina – small hemorrhages, such as occur in diabetic eyes, and detachment of the retina from the back wall of the eyeball become visible.
5. visual acuity and visual field testing by tests.
Who does not know them, the boards in the doctor’s office or at the optician’s with the many letters or numbers?Depending on the visual acuity, one is able to decipher even the lowest row – if not, this suggests short-sightedness or long-sightedness. Color recognition tests indicate color blindness or color vision deficiency. The visual field is tested with the perimeter. The patient looks fixedly into the device and sees small lights flashing from the corner of the eye. The fewer lights he sees, the worse his visual field is – as with glaucoma. Imagine the consequences of a visual field impairment when driving a car!
6. electrophysiologic examinations
The activity of the eye muscles and also the retina can be measured – with small electrodes attached to the eye in the corner of the eye or as a contact lens.
7. x-ray, ultrasound, computed tomography and magnetic resonance imaging.
Imaging techniques are used if a tumor or inflammation is suspected inside the eye – especially after traffic accidents, it must be clarified whether the bony rim of the eyeball is still intact. In addition to infections of the conjunctiva, which can occur in all age groups, some eye diseases are more common in childhood, while others, which are more due to wear and tear or chronic diseases of the overall human system, occur in adults. Injuries to the eye, such as those caused by car accidents or when something gets into the eye through play or work, are not age-related.
Eye complaints in children
Common is co-involvement in the form of conjunctivitis with many childhood diseases (measles, rubella, chicken pox) or a watery eye with hay fever. The eyes should also be checked in case of a long-lasting sinusitis because of the proximity to the nose. Strabismus is an eye misalignment that usually occurs in early childhood and can be successfully treated. Rare but malignant retinoblastoma-a type of cancer that occurs in early childhood-must be removed as soon as possible.
Eye complaints in adults
Many diseases that damage the entire organism also affect the eye. A typical consequence of diabetes is diabetic retinal damage (retinopathy) – the retina is also affected by high blood pressure, and hypertension also promotes the development of glaucoma (also called glaucoma). With advancing age, the elasticity of the eye lens decreases. It is less able to adapt to near or distance vision – and reading glasses are needed. Lens clouding, which can develop into a cataract, is also common. In this case, vision deteriorates progressively until cataract surgery, which is relatively harmless, becomes necessary. Another cause of vision deterioration can be age-related macular degeneration, a common yet little-known disease of the retina that can lead to blindness. Eye symptoms are also common with migraine: sensitivity to light and flashes or rings in front of the eyes are not uncommon.
See a doctor regularly
Many eye diseases could be better treated if everyone considered going to the ophthalmologist as an annual matter of course and did not visit him or her only when symptoms arise. In addition to prescribing glasses or contact lenses, the doctor can compensate for defective vision with laser correction or an implant. It is decided individually whether the operation can be performed on an outpatient or inpatient basis. Of course, there is a special procedure for each disease with medication or surgery – you can find this at the respective disease. Many tips are also offered by the German Association for the Blind and Visually Impaired (DBSV).
Sunglasses protect the eyes
Sun is good for the soul, but direct sunlight damages our eyes. Inflammation of the conjunctiva or cornea are immediate, cataracts and age blindness due to macular degeneration the long-term consequences. Preventive helpful is a good pair of sunglasses. The sense of night driving glasses on the other hand is more than questionable. When ozone levels are high, you should be careful with outdoor sports activities, because ozone irritates the eyes. If you do exercise, don’t forget your glasses – you’ll only increase your risk of injury. You can do something specifically for relaxed and beautiful eyes – especially after working at a screen, your eyes will be glad of an extra portion of attention.When we think of foods containing vitamin A, many of us immediately think of carrots – but there are other foods, such as tuna, lettuce, and milk, that contain vitamin A and its relatives, such as lutein.
