What does that mean?

Often technical terms from the field of ophthalmology (eye care) are difficult to understand for the layperson. With this glossary, we aim to explain the most important terms for you.


In age-related macular degeneration, the photoreceptor cells no longer function correctly and die. Here, a distinction is made between wet and dry macular degeneration.

Test for age-related macular degeneration (AMD): during the check-up, central visual acuity is measured. Examination with the Amsler grid is a very significant test. If the grid lines on the paper do not appear straight for the patient, but distorted, this is a clear indication of macular degeneration.

The English term for this is weak-sightedness. If weak-sightedness is present, the brain cannot correctly process visual impressions. Weak-sightedness can occur if eyesight in children has not developed correctly, refractive power varies between the eyes (anisometropia), or if visual defects or a squint have not been treated.

An anamnesis is a discussion with the patient during which their medical history is requested.

Anisometropia is a difference in refractive power between the two eyes. The term anisometropia is used, for example, if one eye is short-sighted and one long-sighted.

With anterior ischemic optic neuropathy, fat deposits and white blood cells block the arteries of the optic nerve.
The aqueous humour is a clear bodily fluid in the anterior and posterior ocular chambers.

Argon laser is a classic procedure for the treatment of numerous retinal conditions and glaucoma.

Visual impairments in eyesight. Asthenopia (eye-related discomfort) describes a visual impairment that triggers physical discomfort such as headaches, dizziness, malaise, blurred vision or reddening of the eyes.

An astigmatism is an age-related visual impairment. The more severe it is, the more distorted and blurred the vision of those affected. Short- and long-sightedness also develops.


The medical term for baggy eyelids is ‘dermatochalasis’. This is an age-related misalignment of the eyelid triggered by the slackening of the connective tissue.

A basal cell carcinoma (basalioma) is a skin tumour that generally does not form metastases (secondary tumours), but that grows into neighbouring tissue and can destroy bones and cartilage there. These characteristics mean that doctors consider it to be a semimalignant tumour.

See eyelid surgery.

A blind spot is an area at the back of the eye where the optic nerve (nervus opticus) exits the eye. At this point there are therefore no light receptors; the spot really is blind. That we perceive no blind spot in our vision is due to a complementary effect. The visual system uses information provided by the receptors in the vicinity of the blind spot to supplement the visual image.


With a cataract, the lens becomes increasingly cloudy. If left untreated, it can even result in blindness.

A silicone band applied to the eyeball during retinal surgery.

A chalazion is a painless swelling in the eyelid caused by a blockage of a meibomian gland and a localised lipogranulomatous swelling. The slowly developing lump is benign and may recede again by itself over time.

Computer perimetry, threshold perimetry or visual-field measurement is an ophthalmological examination procedure that facilitates the static determination of the visual field.

The conjunctiva is a mucous membrane on the surface of the eye. Only the cornea, the so-called ‘window’ of the eye, is omitted. The conjunctiva is not only considered by the ophthalmologist (inflammation, dry eye, etc.) but also for any general clinical investigation. Since it is quite thin, well supplied with blood and unpigmented, changes are easy to record. Thus, a yellowing occurs in icterus (jaundice) and a white porcelain colour in anaemia or shock.
The cornea is the transparent, curved anterior section of the fibrous tunic that is moistened by lachrymal fluid. It performs the majority of the refraction. It is the front edge of the eyeball.


Dermabrasion is a mechanical procedure to abrade the skin. It may be used in the following cases: in severe cornification of the skin (hyperkeratosis), scarring as a result of accidents or acne.

Diabetes mellitus is a metabolic disorder due to insulin resistance or insulin deficiency and characterised by chronically high blood sugar levels. It is associated with a considerably higher risk of severe comorbidities and complications, including the eye disease ‘diabetic retinopathy’.

This results in small bleeds into the retina and fatty deposits. In advanced cases, it leads to complicated retinal detachments and haemorrhaging into the eyeball.

See double vision.

If you have double vision, this can have a number of causes. For example, this can be caused by overtiredness, squinting, circulatory disturbances or impaired eye muscle function.

With the help of a double-vision test, the ophthalmologist examines the eyes’ mobility, functionality and reflexes. Follow-up testing and therapy depend on the cause of the affliction.


The eye (Lat. oculus) is the visual organ of humans and animals. The appropriate stimulus for this sensory organ in people is electromagnetic radiation with a wavelength of around 350 nm to around 750 nm. In the eye, the received stimulus generates a change in excitation in the efferent nerve pathways. The eye is at the beginning of the visual pathway that transfers this excitation change in the brain to the visual cortex. There and in other superordinate centres, the excitation patterns originating in the eye are then processed to form our perception of light and colour.

  • Vitreous body
  • Eye muscle
  • Sclera
  • Choroid
  • Retina
  • Macula
    Where vision is sharpest
  • Optic nerve
  • Central retinal artery and vein
  • Blind spot
  • Ciliary body
  • Posterior ocular chamber
  • Anterior ocular chamber
  • Lens
  • Pupil
  • Iris
  • Cornea
Eyelid surgery is also referred to as blepharoplasty. This is the surgical tightening of the eyelids. It can be carried out on the upper and lower lid.


The femtosecond laser is used in the state-of-the-art laser procedure to treat glaucoma.

Flickering vision (scintillating scotoma) or visual snow describe a phenomenon whereby small flashing points move about like snowflakes before the eyes. Flickering vision may appear, for example, if you are very tired, have overexerted your eyes or you are suffering from stress.

Fluorescein angiography is the dynamic examination of blood flow in the optic nerve and the retina.


Glaucoma leads to a number of eye diseases. What they all have in common is that they damage the nerve cells and retina and, if left untreated, can lead to blindness.

In an attack of glaucoma, there is a sudden and considerable increase in intraocular pressure. By contrast to other forms of glaucoma, the process is not gradual, but occurs suddenly. This is an ophthalmological emergency.


With an intravitreal injection or intravitreal surgical medication administration (intravitreale operative Medikamentengabe – IVOM), medication is injected directly into the vitreous body of the eye. It is used in the case of macular degeneration, for example.

Your individual lens is determined with the IOLMaster.

The anatomical structure formed by the cornea and iris in the anterior ocular chamber is called the iridocorneal angle.

The iris is the eye’s aperture and is coloured by pigments.

The Ishihara test is a colour vision test. The Ishihara colour charts are used to detect a red–green visual impairment (colour blindness). They were developed by and later named after Japanese ophthalmologist Shinobu Ishihara, who described this test for the first time in 1917.


Keratoconus is a disease of the cornea. Here, the stability of the tissue is impaired and the cornea bulges forwards into a cone shape in the lower section. This results in an irregular astigmatism and the cornea continues to bulge and thin at its tip.


The lens of the human eye is a crystal-clear body, highly convex on both sides and located in the eyeball (bulbus oculi). Its function is to refract light that reaches the eye in order to project a sharp image onto the retina, where it is converted into electrical signals. Consequently, the lens of the human eye is a convex lens because it concentrates the light and conveys it to the retina.


The macula is located at the centre of the retina and has the highest density of photoreceptor cells.

See ‘short-sightedness’.


This laser is used to treat posterior capsule opacity and specific types of glaucoma.

The medical term for night lenses is ‘orthokeratology’. They are applied before going to sleep and correct the shape of the cornea. In the morning, vision is clear again without lenses or glasses.

If tiny capillaries burst, characteristic point-like bleeding can be seen in the retina. This form of diabetic retinopathy is also known as non-proliferative retinopathy. ‘Non-proliferative’ means that newly formed blood vessels are not yet growing.


Ophthalmoscopy is the the examination of the ocular fundus, in particular, the examination of the retina, papilla and the supplying blood vessels.

Optical coherence tomography is a state-of-the-art diagnostic imaging procedure that facilitates a highly specific examination of the optic nerve, the centre of the retina and the macula.

The paired optic nerve represents the first portion of the visual connection to the retina.

See ‘night lenses’.

Orthoptics, a specialist field of ophthalmology, is concerned with the screening, diagnosis and therapy of visual and perceptual disorders.


After an artificial lens is implanted in the case of a cataract, it is possible that the remaining lens capsule will become cloudy. This is called posterior capsule opacity (PCO).

Diabetic retinopathy is a complication of diabetes mellitus (metabolic disorder).

This is ingrowing tissue on the conjunctiva.

This refers to drooping eyelids.


Refractive surgery comprises those surgical interventions that aim to alter the refractive power of the eye and thereby correct the visual impairment. Here, a distinction is made between laser surgery (altering the refractive power of the cornea) and lens surgery (fitting, exchanging or removing lenses).

The retina is layer of tissue around 200 µm thick that lines the inside of the eye like wallpaper. It is the sensory area of the eye and facilitates the perception of light stimuli.

In a retinal arterial occlusion, the eye’s central retinal artery closes. This deprives the retina of oxygen.

With retinal detachment, the light-sensitive layer of the retina – the photoreceptor layer – lifts away from the underlying choroid. Fluid can then gather in the gap between the layers.

With this misalignment, the lids are either rolled inwards (entropion) or outwards (ectropion).


See flickering vision.
The sclera is the casing of the eyeball.

There are two different types of sensory cells – also called photoreceptors – in the retina: the cones and the rods.

The medical term for short-sightedness is myopia. Short-sightedness is a form of visual impairment where distant objects are perceived to be out of focus.

The slit lamp (also: slit lamp microscope) is one of the most important pieces of ophthalmological examination equipment and the ophthalmologist or optician can use it to conduct a stereoscopic inspection of the eyes.

Spherical lenses correct short- and long-sightedness and can be used for an astigmatism, for example.

Strabismus is commonly referred to as squinting. Squinting results in double vision. The brain can compensate for this, but those affected then only see with the healthy eye.

Patients with a subconjunctival haemorrhage have a so-called ‘bloodshot eye’. The discolouration is restricted to the area between the sclera and the conjunctiva and is not dangerous.

Supporting cells are cells that provide structural support to tissue. These are primarily found in the epithelia and tissue in the nervous system.


Tonometry is the medical term for intraocular pressure measurement.

A toric lens is a lens that has two different refractive powers in two perpendicular orientations. At least one of the lens surfaces is shaped like the ‘cap’ of a torus and the other is usually spherical.


The uvea (Lat. uva, ‘grape’), also known as the uveal layer, uveal coat, uveal tract, vascular tunic or vascular layer, is a pigmented layer of the eye beneath the high-scattering (opaque) sclera. The principal functions of this layer are the accommodation, adaptation and nourishment of the deeper-lying retina.

Uveitis is an inflammation of the uvea.


The medical term for this is ‘amblyopia’. Weak-sightedness occurs when vision does not develop correctly. It can also be caused by a squint or varying refractive power between the eyes.