Eye diseases

Eye diseases can affect all areas of the eye. Some develop insidiously and only at an advanced age, while others appear in young people. To prevent permanent damage, it is crucial to have eye problems clarified and treated quickly. Here you can learn more about the most critical eye diseases, how to recognize and treat them, and get valuable tips for healthy eyes.

Common eye diseases

Numerous diseases affect the complex sensory organ and can thus impair vision. For example, infections with viruses or bacteria cause eye inflammation. Some eye diseases are the result of wear and tear. And injuries can also affect the eyes.

Eye diseases can occur in all “components” of the eye or the entire visual system. Here is a selection of common illnesses:


Common eye disease affects the lens of the eye, which is usually crystal clear. In so-called cataracts, known medically as cataracts, the lens becomes cloudy. Cataracts are a sign of old age, especially in industrialized countries.

In addition, other diseases such as diabetes or kidney failure can promote its development. In rare cases, this eye disease is congenital. If vision becomes increasingly tricky, ophthalmologists surgically replace the lens. Medication doesn’t help.


Cataracts involve cloudiness within the lens of the eye, affecting vision. Cataracts occur when the proteins that make up the lens begin to clump together, causing the lens to become cloudy. Cataracts usually require surgery for both cataracts and presbyopia.

Cataract is an eye disease in which visual acuity steadily decreases – up to blindness. Read everything you need to know about cataracts!

Green Star

Also known as glaucoma, glaucoma is one of the most common eye diseases in Germany. The pressure in the eye is usually too high. Doctors distinguish acute glaucoma from a chronic form. The regular variant is characterized primarily by damage to the optic nerve fibers. There is also congenital glaucoma. 

Glaucoma is the second most common cause of blindness in Germany. About eight million people are at risk of developing this eye disease, and around 800,000 already have it. Doctors use medication – usually in the form of eye drops – and surgical procedures to treat it.

The medical term for eye disease that causes vision loss is “glaucoma.” Glaucoma is the second leading cause of blindness, but the vision loss resulting from the condition is permanent. There are two main types of glaucoma: open-angle and angle-closure. Open-angle glaucoma occurs when the fluid that generally circulates your eye becomes trapped and makes your vision blurry. This type most people are familiar with is often referred to as “the silent killer” because when people lose sight of glaucoma, they typically don’t notice the problem until it’s too late.

Here you will find all the important information about the disease and its treatment.

Conjunctivitis and corneal inflammation

The conjunctiva and the cornea, as the outermost layer of the eyes, can become inflamed remarkably quickly. For example, viruses, bacteria, and rare fungi or parasites cause these eye infections. But foreign substances, injuries, and allergies are also possible triggers. Treatment depends on the cause.

Conjunctivitis, also called pink eye, is an inflammation of the conjunctiva, the clear, protective membrane covering the eyes’ whites. It is caused by an allergic or infectious process and is easily spread from person to person.

Conjunctivitis can have many causes. How the inflammation becomes noticeable and how to treat it, read here!
Inflammation is a normal response to injury or infection. However, inflammation can also be caused by environmental factors, such as infection, allergens, sun damage, smoking, and pollution. Some elements (such as smoking or pollution) are out of your control. However, with a better understanding of the symptoms and types of eye inflammation, you can reduce eye discomfort, decrease discomfort related to eye inflammation, and help you achieve better eye health.
Read more about corneal inflammation!

Macular degeneration

This eye disease primarily affects people over 60 years of age. This is why it is also called age-related macular degeneration (AMD). The macula, the place of sharpest vision in the eye, “ages” to a certain extent due to disturbed metabolic processes.

In industrialized nations, AMD is the most common cause of blindness in old age. There is no direct therapy. Nevertheless, there are now various approaches that doctors can use to slow down the progression of eye diseases.

Age-related macular degeneration (AMD), also known as age-related blindness, is a leading cause of vision loss among people ages 50 and older. Some areas have reported a 10 to 20 percent increase in new cases over the past six years. AMD is caused by damage to the back of the eye that gradually leads to the loss of central vision, making such activities as reading, driving, or watching television difficult. There is no cure for AMD, but by taking measures to protect your eyes and your general health, you can delay the progression of the disease.

Macular degeneration is the most common cause of severe visual impairment in adults. Distorted visual perceptions are alarm signals. Read more.

Retinal detachment

In this eye disease, the innermost layer of the retina detaches from its base. As a result, the light that hits the separate parts of the retina can no longer be converted into electrical signals. Those affected complain of flashes of light and black dots. An increasingly spreading dark shadow also speaks for a retinal detachment.

The retina usually tears beforehand, for example, because the vitreous body in the eye becomes smaller and lifts off. This vitreous humor typically fills the inside of the eyeball and liquefies with age. Accidents, eye operations, and tumors can also cause eye disease. Doctors use lasers for smaller detachments, and they operate on larger ones.

The eyes are often the window to the soul, so it’s no shock that retinal detachment surgery is one of the most commonly performed surgeries on humans. Retinal detachments are among the most common of all eye surgeries. But a retinal detachment can be a severe eye emergency for millions of people. Each year, about 40,000 people in the United States experience a retinal detachment.

Flashes of light and blurred vision can herald a detachment of the retina. Read everything you need to know about retinal detachment here!

Inflammation of the eyelids

Eye diseases can also affect the eyelids. For example, the eyelid becomes inflamed in blepharitis, usually due to bacterial infection. If certain bacteria attack the eyelid gland, doctors speak of a stye. Part of the glands can also become inflamed without pathogens playing a role. Clogged gland ducts lead to a so-called hailstone.

Blepharitis is an inflammation of the eyelids, commonly characterized by redness, inflammation, and excess oil production by the glands located at the base of the eyelids. Blepharitis often occurs as a complication of another eye disease, such as rosacea and chronic dry eye syndrome. Symptoms can include significant irritation and itchiness, sensitivity to light, and decreased vision. Blepharitis can be treated with warm compresses, prescription ointments, and lid scrubs, but severe cases may require surgical treatment.  Read on now!

Eye diseases from A to Z

In addition to the above, there are numerous other eye diseases. They can be the result of other conditions, for example. In diabetic retinopathy, for example, the blood vessels in the retina change due to diabetes mellitus. The blood vessels there can also close completely, for instance, due to high blood pressure.

In addition, eye diseases occur not only in the eyeball but also in the rest of the visual system. Other components can also become inflamed, such as the optic nerve (optic neuritis) or the tear ducts (dacryoadenitis). The eye socket, in turn, can break (orbital floor fracture) or the associated tissue can become inflamed (orbital cellulitis). There are also various tumor diseases of the visual apparatus.

You can find more eye diseases here, clearly arranged from A to Z:

Common Eye symptoms

Eye diseases can be as varied as there are eye diseases. Most of the time, the eye symptoms disrupt normal vision, even if it is just a harmless protective reaction. But they can also be signs of a severe illness. Therefore, take any persistent eye symptoms seriously and have your vision problems clarified.

Typical symptoms of eye diseases include:

  • Watery eyes occur, for example, as a protective reaction to foreign substances, but also in the case of eye inflammation or diseases of the lacrimal system.
  • Reddened eyes are typical of conjunctivitis or corneal inflammation. For example
  • Dry eyes are caused, for example, by various environmental influences such as long periods of screen work or draughts. But diseases of the thyroid gland, Sjögren’s syndrome, or diabetes can also be hidden behind it. 
  • Above all, itchy eyes are annoying and often the result of an allergy.
  • Puffy eyes often appear in the morning and are usually harmless. However, in the context of allergies, cardiac insufficiency, and kidney failure, increased water can accumulate around the eyes and in the conjunctiva (chemosis).
  • Burning eyes occur, for example, with inflammatory eye diseases. Even very dry eyes can burn.
  • Eye pain is typical of glaucoma. Some sufferers also find burning eyes very painful.
  • It is not only irritants such as dust, eyelashes, or smoke responsible for a foreign body sensation in the eye . Inflammatory eye diseases can also sometimes feel “foreign.”
  • Vision problems occur with almost every eye disease. Flashes of light, soot rain, flickering, shadows, double vision, visual impairments up to and including loss of vision – the causes of these eye symptoms can sometimes be severe and should therefore be clarified quickly.
  • Sensitivity to light can have many causes. In addition to numerous eye diseases, these include headache syndromes such as migraines, infectious diseases, or nervous system diseases.

In addition to swelling, redness, and pain around the eye, for example, on the eyelid or the tear sac, can also occur. Sometimes the eyes protrude unnaturally (“bulb eyes“). Doctors call this eye symptom Exophthalmos (Bulging eyes), which can be seen, for example, in the thyroid disease Graves’ disease.

The opposite, enophthalmos, is, in turn, a sign of an orbital floor fracture. With a drooping eyelid (ptosis) and narrow pupils (miosis), the sunken eye also forms what is known as Horner’s syndrome. This indicates nerve damage, for example, due to tumors, strokes, or vascular injuries.

Dark circles, also known as circles under the eyes, are a common cosmetic problem. It is caused by the accumulation of blood in the thin skin of the eye area. Dark circles are a common complaint about cosmetic treatments, particularly light-based treatments that use laser or intense pulsed light to treat vascular conditions. Some causes include poor nutrition, lack of sleep, excessive caffeine consumption, smoking, and aging.

Find out here where dark circles come from and what you can do about them.
Dry eyes are a common problem for many people. They can be caused by many factors, including age and hormonal changes. But, there are many steps you can take to keep your dry eyes from becoming worse.
Dry eyes occur when the surface of the eye is no longer properly moistened with liquid. Read more about causes and therapies.


More than 60 percent of adults in Germany are ametropia. Those affected only see clearly in a specific area. Opticians distinguish between the following forms:

  • Short-sightedness (myopia): Affected people see things well up close but have difficulty seeing things far away.
  • Long-sightedness (hyperopia): Affected people see things close up badly, whereas far-sightedness is possible
  • Age-related farsightedness (presbyopia): The lens can move less and less with increasing age. But this is important for close-up vision. As a result, older people find it increasingly difficult to read.
  • Astigmatism: The crooked cornea interferes with the refraction of light entering the eye. Depending on the extent, those affected no longer see sharply but are blurry.

Impaired color vision

In addition to visual acuity, color vision can also be affected. Not all cones of the retina, which are typically responsible for recognizing colors, work. This eye disease is congenital and is particularly common in men as red-green color deficiency. Total color blindness is very rare.

Squinting (strabismus)

If one eye deviates from the normal visual axis, the person concerned squints. Young children are particularly often affected. The cause usually lies in the genetic make-up. Treatment is important because children “switch off” one or both eyes to avoid seeing double, which can result in permanent visual impairment.

Nervous disorders can also cause squinting. The nerves that are used to move the eye muscles and thus the eye are affected. If an eye muscle is paralyzed, eye movements in certain directions are no longer possible.

Strabismus, also known as the Crossed eye, A crossed eye is a vision condition that can occur at any time during a child’s development. It can be temporary, or it can stick around for some time. According to the American Association for Pediatric Ophthalmology and Strabismus, crossed eyes can develop before a child is born or later in life. They can even develop at birth or as late as a few months old.

In strabismus (squinting), the visual axes deviate from each other when focusing on a specific object. Learn everything you need to know about squinting.
Red Green eye weakness is a severe condition resulting from a blood vessel in the eye become blocked. This condition is called Ischemia of the retina. Ischemia of the retina causes permanent damage to the cells in the retina. If the blockage happens long enough, the retina can die. Some common symptoms of this condition include blurry vision, inability to see color, and flashes of light.
In the case of red-green weakness, those affected can only distinguish between red and green with difficulty or not at all. Read more about it here!

Eye diagnostics

An ophthalmological examination is necessary, among other things, if visual disturbances occur, the eye has been injured or if vision is gradually declining. From the age of 50, ophthalmologists recommend regular standard examinations. Otherwise, insidious disease processes are often noticed too late, especially when the healthy eye can still compensate for the dwindling vision of the other eye. 

Among other things, the ophthalmologist tests eyesight, which includes visual acuity and color vision. He also checks the field of vision, i.e., what a person sees in their surroundings without moving their eyes or head ( perimetry ). He also examines whether the conjunctiva and cornea of ​​the eyes are intact. The doctor can see how the pupils react by alternating the light into the left and right eye.

The doctor can also check the inside of the eye for eye diseases using special equipment. With a so-called slit lamp, he examines the individual sections of the eye. During fundoscopy, it reflects the fundus of the eye. In this way, the doctor recognizes damage to the retina and blood vessels. Depending on the eye disease, there are additional special examinations.

Telltale eyes

Telltale eyes

Telltale eyes are a symptom that something is wrong with the body. Telltale eyes can be either pink or blue, depending on which organ is affected. The eyes can be red, teary, or bloodshot. Telltale eyes can indicate an infection, a deficiency, or the result of another illness. Telltale eyes can be an indication of serious medical issues. Telltale eyes can indicate a severe health risk.

High blood pressure, diabetes and the like – these diseases can be seen in your eyes.

Eye treatment

The eyes are complex and delicate organs. Throughout life, the likelihood of developing several eye diseases increases. Not everyone can be healed. Detected early, its progression can often be slowed down. Some acute complaints must also be treated as quickly as possible to avoid permanent damage.

The therapy always depends on the respective eye disease. Special eye drops or eye ointments are often sufficient. Sometimes, however, an eye operation is necessary. Injuries, chemical burns, and foreign objects in the eye usually constitute an emergency. First aid is crucial here.

Ametropia can be treated much more quickly. Visual aids such as glasses or contact lenses usually wholly compensate for this. Operations can also help ( refractive surgery, including various laser procedures ).

Glasses are optical aids that correct defective vision (ametropia). Read everything you need to know about it.

Refractive surgery involves changing the shape of the cornea, which is the eye’s clear covering. It corrects vision problems resulting from excess curvature or an abnormal cornea condition. The surgeon cuts a small flap in the cornea, then reshapes it using special tools. In these cases, the cornea is reshaped by flattening it out, making it thinner, or changing the shape of the curvature. These procedures do not correct nearsightedness, farsightedness, astigmatism, or problems with focusing. In most cases, vision will be blurred for several weeks after surgery, and vision may get worse before it gets better.

The term refractive surgery refers to all eye operations that change the refractive power of the eye. You’ll find more about it here!

Healthy eyes

Screen work and the often extended use of smartphones, tablets, or TV strain the eyes. The amount of time most people spend indoors is also not good for their eyesight.

But you can also do something good for your eyes. Regular eye training, a balanced diet, and the right amount of relaxation promote eye health and can successfully counteract many eye diseases.

Scientific standards:

This text corresponds to the requirements of specialist medical literature, medical guidelines, and current studies and has been checked by medical professionals.