Glossary

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Accommodative: The capability of the eye to focus directly both on close and distant objects without any assistance. The reduction of this capability as from the 45th year of age is known as age-related presbyopia: the person in question then requires reading spectacles.
Accommodative intraocular lenses: New innovative intraocular lenses with the target of restoring the accommodation of the eye. Accommodative intraocular lenses (e.g. 1 CU intraocular lens) can be implanted in the eye within the framework of a cataract operation.
Ametropia (= refractive error): Deviation from normal sight: short-sightedness (myopia), far sightedness (hyperopia) and corneal astigmatism.
Aniridie: Die Aniridie ist ein angeborenes oder durch eine Augenverletzung entstandenes Fehlen der Iris. Fehlt nur ein Teilstück und es ist noch eine Restiris vorhanden, spricht man von partieller Aniridie.
Astigmatism: A sight deterioration caused by irregularities of the cornea, whereby instead of seeing individual points of an object, bars or stripes are seen.

Cataract: Opacity of the lens as a result of the natural aging process, pharmaceuticals or eye injuries.
Ciliary muscle: Muscle of the ciliary, which affects the accommodation (capability of the eye to focus sharply on close-up and distant objects). Through tightening, the zonula fibres are relieved, whereby the young lens is bent to a greater extent and thus develops stronger optical power.
Concave: A lens which is flatter in the centre than at the edge (diverging lens) is known as a concave lens. Concave spectacle lenses (minus lenses) are used for short sightedness.
Convex: A lens which is thicker in the centre than at the edge (converging lens) is known as a convex lens. Convex spectacle lenses (plus lenses) are used for far sightedness and age-related presbyobia.
Cornea: This forms the forward clear transparent part of the exterior eye skin. Its diameter amounts to approximately 11 to 12 mm, and its thickness in the centre to between 0.5 and 0.6 mm.

Dioptre: Measurement unit of the refracting power; if the eye is short sighted, a minus sign is shown before the value of the spectacle lens or the contact lens.

The refracting power of the lens is indicated in the dioptre unit (in short D). The dioptre figure indicates the reverse value of the focus measured in metres. A lens with 4.0 dioptre thus has a focus of 0.25 m.

Glaucoma: Illness during which the optic nerve is damaged by an increase in of the internal pressure of the eye.

Haptics: Exterior elastic continuation of the artificial lens, in order to anchor the lens in the eye capsule.
Hyperopia (= far sightedness): Refractive error: focused vision of distant objects, unfocused vision of close-up objects.

Implantation: (Surgical) introduction of artificial components into the body.
Intraocular lenses: Synthetic lenses, which today are are implanted as a replacement for the body's own lenses in the interior of the eye during a cataract operation. One makes a difference between posterior chamber lenses (standard) and anterior chamber lenses, as well as foldable lenses (made of acrylic or silicone) and non-foldable lenses (made of Plexiglas).
Iris: Regenbogenhaut, die dem Auge die Farbe gibt. Sie steuert die Pupille (Blendenöffnung), die sich vergrößern und verkleinern kann.

Lasik: Laser in situ keratomileusis. Process of refractive surgery for the correction of refractive error through laser removal (excimer laser) of certain areas of the interior of the cornea.

Myopia (= short sightedness): Refractive error: focused vision of close-up objects, unfocused vision of objects at a greater distance.

PMMA: Polymethylmethacrylicate (material similar to Plexiglas).
Presbyopia (= age-related sight deterioration): As from approximately the 45th year of age the capability of looking in a focused manner at close-up objects deteriorates significantly. The eye lens loses elasticity, whereby the focusing is reduced. Reading spectacles are then necessary.

Refracting power: Reverse value of the difference between the lens and its focus (1/m).

Ophthalmologist and opticians indicate the refracting power for lenses (spectacle pass). The optical power is expressed in dioptre (dpt). The optical power of the cornea amounts approximately to 43 dpt and that of the eye lens to between 18 and 32 dpt. In the case of short sightedness (myopia) the patient requires spectacles with negative optical power (so-called minus lenses), and in the case of far sightedness (hyperopia) and age-related presbyopia spectacle lenses with positive optical power (so-called plus lenses).
Refractive surgery: Permanent correction of refractive error as aresult of operations. One differentiates between processes in corneal surgery (LASIK, PRK, keratotomy) and lens surgery (phakic intraocular lenses, clear lens-extraction, "PRELEX").

Staff vision: A sight deterioration caused by atrophy of the cornea, whereby instead of seeing individual points of an object, bars or stripes are seen.