Retinal diseases

What are retinal diseases?

Retinal disease damages the retina in the eye. This layer contains the light-sensitive sensory cells (photoreceptors) that are essential for color vision and the perception of black and white in twilight.

Experts distinguish between different types of retinal diseases. In medical terminology, they are called retinopathies. Examples include age-related macular degeneration (AMD), diabetic retinopathy, retinitis pigmentosa, vascular occlusion in the retina or retinal detachment. However, there are many other forms, which can also be hereditary and occur with varying frequency.

Retinal diseases can have very different causes. Age-related macular degeneration is usually related to age, while diabetic retinopathy is a complication of diabetes mellitus. In the case of retinitis pigmentosa, the causes lie in the genes – this form of retinal disease is therefore hereditary. In retinal vascular occlusions, arteries or veins in the retina are blocked. And the cause of retinal detachment is usually a tear or hole in the retina.

The symptoms depend on the cause of the retinal disease. What they all have in common is a deterioration or loss of vision. The light-sensitive photoreceptors – the rods and cones – are damaged or die. The ability to see colors and black and white in twilight and darkness decreases.

The treatment depends on the type of retinal disease. Specialists try to slow down the loss of vision, alleviate the symptoms and – if present – treat the underlying disease adequately. They also treat any complications of retinopathy.

Doctors differentiate between so-called “medical retina” – treatment without surgery – and “surgical retina” – treatment with surgery.

Surgical Retina

The term “Surgical Retina” covers a wide range of eye diseases that affect the vitreous body and/or the retina. What they all have in common is that a surgical procedure on the vitreous body or the retina is necessary as initial treatment. Many eye diseases that belong to the “Surgical Retina” group are emergencies. This means that doctors have to operate as quickly as possible in order to save sight. The majority of these cases can now be treated with the help of modern surgical methods.

Some examples from the Surgical Retina section, where quick action is particularly important:

• Retinal detachment: The retina detaches from the underlying layers.
• Bleeding into the vitreous body, for example as a result of an injury or vitreous detachment.
• Hole in the macula (macular hole) – a hole forms at the point of sharpest vision, the macula. The cause is thought to be tensile forces that act on the macula and cause it to tear.
• Hole in the retina (retinal foramen) – for example due to degenerative processes or vitreous detachment.
• Epiretinal membrane: A thin layer of tissue or a fine film forms over the macula – the central point of the retina and the site of sharpest vision.
• Choroidal tumors – these tissue growths in the eye can be benign or malignant.
• Intraocular lymphoma – a non-Hodgkin’s lymphoma that can affect the eye as well as the central nervous system (CNS).
• Replacement of the intraocular lens (IOL), for example due to dislocation or loosening (luxation)
• Traumas (injuries)
• Endophthalmitis – a serious infection within the eye

Retinal diseases – frequency and age

The frequency and age always depend on the type of retinal disease. Some examples:

• Age-related macular degeneration: AMD generally affects people over the age of 50. The most important risk factor is age. The incidence therefore increases with age: Between the ages of 65 and 75, around 1 in 100 people are affected. For the over-85s, the figure is already 10 to 20 out of 100 people. There are two forms of this retinal disease: dry (more common) and wet (less common) age-related macular degeneration. In industrialized countries, AMD is the most common cause of severe visual impairment in the elderly.
• Diabetic retinopathy: This complication occurs in people with diabetes mellitus whose blood sugar has not been well controlled in the long term. Approximately 9 to 16 percent of type 2 diabetics and 24 to 27 percent of type 1 diabetics develop the disease. In the western world, this retinal disease is the most common cause of blindness in 20- to 65-year-olds. In Switzerland, too, diabetic retinopathy is the most common cause of visual impairment before the age of 70. Men and women can fall ill in equal measure.
• Retinitis pigmentosa: This is not just one disease, but a whole group of hereditary retinal diseases. Around three million people worldwide are affected. It usually begins in adolescence or middle age. In middle adulthood, it is one of the most common causes of vision loss.
• Retinal vascular occlusion: Important veins (more common) or arteries (less common) in the retina become blocked – the supply of oxygen and nutrients to the photoreceptors then fails. Arterial occlusions affect men about twice as often as women. Mostly older people fall ill with it. Venous vascular occlusion often occurs between the ages of 50 and 70.
• Retinal detachment: This is comparatively rare. Experts estimate that around 1 in 10,000 people are affected each year. Older and very short-sighted people are most frequently affected. Rarely, retinal detachment occurs in younger and normally sighted people. It is more common in men than in women.

Retinal diseases: Causes and risk factors

The causes of retinal diseases can be very different. There is usually another disease behind the retinopathy. What they all have in common, however, is that the light-sensitive sensory cells in the retina are damaged and die. Vision deteriorates – to the point of blindness.

Retinal diseases – when cones and rods suffer

There are two types of photoreceptors in the retina, which differ in shape and react to different wavelengths of light:

• Cones are mainly active in daylight and are responsible for color vision. There is a region in the retina where a particularly large number of cones are located – the macula (yellow spot). This is also the area of sharpest vision. A person has around six million cones in the retina. They contain the visual pigment opsin – specific for red, green and blue.
• Rods are more sensitive than cones and react to even small amounts of light. They are particularly active in low light conditions and enable vision in twilight. Therefore, even in the dark, a person can still see well in black and white and distinguish outlines, shadows and shapes. The rods are more strongly located in the peripheral zones of the retina. A human has around 125 million rods. They contain the light-sensitive dye rhodopsin.

Age-related macular degeneration: causes

The cause of age-related macular degeneration (AMD) is a metabolic disorder in the retina. The most important risk factor for this is a person’s age. In AMD, waste products are formed that the body cannot break down. They accumulate in the center of the retina (macula) and disrupt its supply of oxygen and nutrients.

There are two forms of AMD:

• Dry age-related macular degeneration: The photoreceptors are gradually destroyed and sometimes the visual pigments also change. This form is more common.
• Wet age-related macular degeneration: New blood vessels form underneath the retina due to the deposits. They grow into the retina and can lift it. If they become permeable, fluid and blood enter the retina and damage the photoreceptors.

If age-related macular degeneration already runs in the family, relatives have a higher risk of developing the retinal disease. Smoking also increases the risk of AMD – it even affects some people at a young age.

Diabetic retinopathy: causes

The cause of diabetic retinopathy is diabetes mellitus. It is a consequence if the blood sugar level is permanently elevated. Diabetes attacks the blood vessels, including in the retina – they become “sugared”. Diabetic retinopathy affects both type 1 and type 2 diabetics. The longer the diabetes lasts and the older a diabetic is, the greater the risk of this retinal disease. This is why it is so important to keep your blood sugar levels well controlled.

Retinitis pigmentosa: Causes

The causes of this group of retinal diseases lie in the genes. They are therefore hereditary. Parents can pass on the “sick” gene to their offspring. Sometimes one gene from one parent is enough to cause retinitis pigmentosa. Sometimes two genes from mother and father are necessary. Inheritance can also take place via the X chromosome – in which case it is mainly men who are affected because they inherit it from their mother.

What all forms have in common is that the light-sensing cells gradually “perish”. The rods are usually affected first, followed by the cones. Vision deteriorates progressively – to the point of blindness.

Retinal vascular occlusion: Causes

Vascular occlusions in the retina can affect the veins (more frequently) and arteries (less frequently). They can have various causes:

• Venous retinal occlusion: The central vein in the retina or one of its side branches becomes occluded. The most common cause is a blood clot (thrombosis) in the retina. The supply of oxygen and nutrients is then reduced or completely interrupted. People with high blood pressure, vascular calcification (arteriosclerosis) and diabetes mellitus, for example, have an increased risk of retinal vein occlusion.
• Arterial retinal occlusion: The central artery of the retina or one of its side branches can become occluded. The most common cause is an embolism, where a blood clot breaks free from another part of the body and is carried into the arteries of the retina. An arterial occlusion in the retina is often caused by an existing cardiovascular disease.

Retinal detachment: causes

The cause of retinal detachment is usually a tear or hole in the retina – often as part of a vitreous detachment. Tensile forces act on the retina and cause tears to form. Subsequently, vitreous fluid penetrates, accumulates under the retina and lifts it off.

Risk factors for retinal detachment include

• severe myopia
• other retinal diseases such as diabetic retinopathy, age-related macular degeneration, severe inflammation and infections
• Eye tumors
• Cataract operations(cataracts)
• Eye injuries
• Previous retinal detachment

Symptoms: Retinal diseases reduce vision

The symptoms of retinal diseases always depend on the underlying disease of the retina. What they all have in common, however, is that their vision deteriorates. This process can be slow and gradual or acute and rapid – depending on the retinal disease. In the worst case, those affected can go blind. The most important symptoms of various retinopathies at a glance!

Age-related macular degeneration: symptoms

The symptoms of age-related macular degeneration (AMD) depend on whether the dry or wet form is present.

Dry AMD: Symptoms

With dry AMD, the onset of symptoms is gradual and gradual. They can affect one eye or both eyes.

• Visual difficulties in poor lighting conditions – this can affect reading or manual work, for example.
• Problems adapting to dark lighting conditions, such as at the movies or in dim light in a restaurant
• Blurred vision
• Impaired color vision, such as the intensity or brightness of colors
• Problems recognizing faces
• Blurred or black spots in the field of vision

Wet AMD: symptoms

In wet AMD, the onset of symptoms is acute and sudden and they deteriorate rapidly:

• Distorted vision – straight lines appear curved, wavy or crooked and objects appear further away than they actually are
• Disturbance of central vision – e.g. objects on which you focus your gaze appear blurred or out of focus
• Disorders of color perception
• Blurred or dark spot in the field of vision

In the case of advanced AMD, deceptive perceptions can also set in: Affected people then see geometric shapes, animals or people.

Diabetic retinopathy: symptoms

Doctors distinguish between two forms of diabetic retinopathy – non-proliferative and proliferative retinopathy. In the first case, no new blood vessels grow and the visual disturbances are still mild. In the second case, new vessels form which can grow into the vitreous body. This is when diabetic retinopathy becomes more noticeable.

In most cases, the retinal disease progresses gradually and those affected increasingly lose their vision. However, the symptoms can also become acute if the retina becomes detached.

The most important symptoms of diabetic retinopathy are

• Decreasing visual acuity – a stronger visual aid usually does not bring sufficient improvement
• Blurred vision and distorted vision
• Difficulties with reading
• Disorders of the sense of color

In case of retinal detachment:

• Flashes of light
• “Soot rain” – those affected see black dots
• “Dark curtain” in the field of vision
• Loss of vision and blindness

Retinitis pigmentosa: symptoms

The most important symptoms of retinitis pigmentosa are

• Poor vision at dusk, night blindness
• Increased sensitivity to glare
• Peripheral visual field loss (on the sides)
• Disorders of color vision
• Poor perception of contrasts
• Difficulties adapting to changing lighting conditions
• Narrowing and loss of the visual field

Retinal vascular occlusion: Symptoms

The symptoms of retinal vascular occlusion depend on whether the veins (more common) or arteries (less common) are affected.

An arterial occlusion can be recognized by the following rapid onset symptoms:

• Central artery: Sudden unilateral blindness without pain or massive impairment of vision and perception of light phenomena
• Arterial branch: Sudden loss of visual field or visual impairment in the area of the vessel occlusion

A vein occlusion usually progresses more slowly and the symptoms set in gradually. Warning signs of a vein occlusion in the retina are:

• Deterioration of vision, but without pain
• Venous branch: The occlusion can also occur without any symptoms.

Retinal detachment: symptoms

• Early symptoms: flashes of light, bright flickering (usually on one side, clearer in the dark than in the light), dark spots (“soot rain”), cobwebs
• Detachment of the retina: Perception of a wall or a shadow in the visual field – depending on where the retina has detached
• If the retina has detached at the macula: blurred, distorted and impaired vision

If you have any kind of vision problem, you should always consult your ophthalmologist as soon as possible. In this way, retinal disease can be detected and treated in good time.

Retinal diseases: Diagnosis with us

The diagnosis of a retinal disease always begins with a discussion of your medical history (anamnesis). We ask you some questions, for example:

• What symptoms do you experience exactly?
• When did you first notice them?
• How intensively are they pronounced?
• Did the symptoms start acutely or gradually worsen?
• Do you have any known underlying diseases? z. e.g. diabetes mellitus, cardiovascular diseases?
• Have you already been diagnosed and treated for an eye disease? z. e.g. short-sightedness, retinal detachment
• Are there any eye diseases in your family? If yes: Which ones?

This is followed by various eye examinations, during which we take a closer look at the eyes. Ophthalmoscopy and fundoscopy shed more light on the condition of the eyes and their structures. We can diagnose damage to the retina and other parts of the eye. A microscope with a powerful light source is used. This allows the back of the eye to be enlarged and well illuminated.

An examination of the visual field, a test for night blindness and electroretinography (test for the function of the photoreceptors through stimulation) also provide additional information.

The further diagnostic methods depend on the suspected cause and whether and which underlying disease is present. As a rule, a blood test is standard. Imaging procedures are usually also used, for example:

• Ultrasound examination: Sonography works with sound waves.
• Fluorescein angiography: The blood vessels are made visible with a dye.
• Optical coherence tomography (OCT): The retina can be easily visualized with the help of weak laser light.
• Computed tomography (CT): This method works with X-rays and creates detailed tomographic images.
• Magnetic resonance imaging (MRI = magnetic resonance imaging): Radiologists use strong magnetic waves and obtain high-resolution cross-sectional images of the eye.

Retinal diseases: Prevention, early detection, prognosis

Doctors are familiar with a wide variety of retinal diseases, which in turn can have different causes. Therefore, there are no general measures for the prevention and early detection of retinal diseases in the doctor’s office. Age-related macular degeneration is related to age, while retinitis pigmentosa is hereditary. Neither your age nor your genes have any influence – so you cannot prevent these retinal diseases.

However, you can tackle diabetic retinopathy yourself. Pay particular attention to long-term well-controlled blood sugar levels and have your diabetes adequately treated. Cardiovascular diseases such as high blood pressure, existing eye diseases or defective vision should also be treated by a doctor. In this way, you can prevent damage to the retina to a certain extent – or at least delay it. You should also have regular eye examinations by an ophthalmologist: these are important for the early detection of retinal disease.

A healthy lifestyle can also help the eyes. This includes, for example, a healthy diet, not smoking and moderate alcohol consumption.

And finally, the general advice is: always consult your ophthalmologist promptly if you have any kind of vision problem!

Progression and prognosis of retinal diseases

The course and prognosis of a retinal disease cannot be predicted in general terms, but vary from person to person. The type of retinal disease is always decisive.

As a rule, damage to the retina cannot be reversed. However, doctors can often halt the progression of retinal disease and thus preserve vision for longer. The symptoms can also usually be alleviated. Sometimes, however, eyesight cannot be saved and there is a long-term risk of blindness.

Self-help groups

The exchange with people who are affected by the same disease can be a great support in coping with the disease. Advice on finding a suitable self-help group is available from Selbsthilfe Zürich. Self-Help Zurich and the University Hospital Zurich are cooperation partners in the national project “Health literacy thanks to self-help-friendly hospitals”.

Retinal diseases: Treatment depending on the cause

The treatment for a retinal disease always depends on the type of retinopathy, the cause and the symptoms. Doctors differentiate between so-called “medical retina” – treatment without surgery – and “surgical retina” – treatment with surgery.