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The eye has the ability to adapt to near and far vision. This is achieved by a change in shape of the natural lens. The elasticity of the lens and their accommodation capability declines with age. As a consequence of this development many people need reading glasses later in life.

AMD (= age-related macular degeneration)
Macular degeneration is a medical condition which usually affects older people and results in a loss of vision in the center of the visual field (the macula). It is caused by the loss of cells in the central part of the retina and produces distortion, reduction of visual acuity; decrease of contrast sensitivity and color vision can have a detrimental effect on reading ability.

This is an error of the eye in focusing the light. Different types are possible: myopia, hyperopia and astigmatism.

The absence of the iris, congenital or caused by an eye injury. In some cases just a part of the iris is affected, with parts of the natural iris remaining, called partial aniridia.

Aphakia means the absence of a lens in the eye.

Description of a surface, which isn´t circular but a changing radii of curvature from the center to the periphery. Intraocular lenses with an aspheric design can reduce spherical aberrations to improve vision.

Astigmatism is a refractive error of the eye leading to different refractions in different meridians. Without any correction objects are seen blurry or with a shade and in case of a higher amount of astigmatism objects are distorted. Astigmatism can be corrected with glasses, contact lenses or surgery.
Blue light protection
The blue light protection e.g. of the yellow IOLs imitates the properties of the natural lens and protects the retina against the harmful high-energy blue light.
Cataract is the clouding of the lens as a result of the natural ageing process, medications or eye injuries. The name cataract is derived from the fact that people who are suffering from advanced cataract show a grey color behind the pupil. In Germany, 600 000 patients are operated on every year to remove the clouded lens and replace it by an artificial intraocular lens.
Clear Lens Extraction
Correction of a refractive error by surgical replacement of the natural lens by an intraocular lens, when no cataract is present.
A lens that is thinner in the central zone than at the edge. This geometry provides a minus power, which is used to correct myopia.
A lens that is thicker in the central zone than at the edge. This geometry provides a plus power, which is used to correct hyperopia and presbyopia.
Is the transparent and clear front part of the eye that refracts light and generates two-thirds of the eye´s total optical power. Its diameter is about 11 to 12 mm, its thickness 0.5 to 0.6 mm in the center.

The refractive power of optics is specified as diopter (D), which is the inverse amount of the measured focus length in meters. A lens with the power of 4.0 D has a focus length of 1/4 m.

The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments. The FDA is responsible for the approval of drugs and medical devices. Founded in 1927, the FDA regulates access to the U.S. market.
 An eye disease that develops when too much pressure in the eye damages the optic nerve which, if left untreated, could lead to blindness.
A peripheral part of the intraocular lens that is responsible for the fixation of the IOL in the eye.
Refraction error that induces a blurred vision of close objects and clear vision in the distance.
The act of inserting a medical implant.
Intraocular lens (short: IOL)
An artificial lens, which is implanted in cataract surgery after the extraction of the original crystalline lens.
The iris is the part of the eye that defines the eye´s colour. In its center remains an opening – the pupil, which as the aperture of the eye controls, the light incidence onto the retina.
Short form for Laser in situ keratomileusis. A method of refractive surgery to correct vision defects by laser ablation (excimer laser) in the interior of the cornea.

The macula is the point of sharpest vision, located in the center of the retina
Marfan Syndrome
Genetic, dominant hereditary connective tissue disease, named after the French pediatrician Marfan, who first described the syndrome more than 100 years ago.
The short form for micro incision cataract surgery which describes a modern procedure in cataract surgery to minimize the incision size to smaller than 2.0 mm.
Monofocal lens
Intraocular lenses with one focal point that provides sharp vision at only one distance (usually in the distance). For near vision additional reading glasses are needed.
Multifocal lens
Special intraocular lenses that produce more than one focal point and therefore provide good vision at several distances.
Myopia (=nearsightedness/ short sightedness)
Refractive error that, if uncorrected, provides sharp vision close to the eyes and blurred vision in the distance.
Is the science of diseases and disorders of the eye, the visual sense and their medical treatment.

Polymethylmethacrylat (PMMA), also known as plexiglass or acrylic glass is a material that was used for the first IOLs. The material is not foldable and so quite a big incision size is required for implanting the lens into the eye. Nowadays PMMA optics are barely used in industrial countries or only as an exception.
Over the age of 45, the ability to clearly focus on near distances does reduce noticeably as the crystalline lens loses its elasticity. Reading glasses become necessary.
Pseudophakia is the medical term for the presence of an artificial lens in the eye. The main reason for pseudophakia is cataract surgery.
Refractive power
The refractive power indicates how much a light beam is refracted when passing through an optic. The specification is in diopters (D), which is mathematically defined as the inverse distance between the lens and its focus point taken in meters (m−1). In cases of myopia, a lens with minus power is used to correct the vision. Hyperopic and presbyopic eyes are corrected with a plus powered lens.
Refractive Surgery
Refractive eye surgery is an ophthalmic surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. There a two different types: either reshaping the cornea by laser treatment (LASIK; PRK) or secondly correcting the refractive error by implanting an intraocular lens (phacic IOLs, Clear Lens Extraction)
The part of the eye that consists of light sensitive receptors. These receptors are connected to the optic nerve and send the incoming light information to the brain to receive images.
Toric intraocular lens
Special intraocular lenses with cylindrical power to compensate for astigmatism.

UV Filter
Invisible ultraviolet light can cause harm to important structures of the eye. Therefore, it is a standard with today’s IOLs that UV filters are integrated that block harmful UV rays

Visual acuity
Describes the basic function of the eye to see objects sharply and in detail. There are different charts for testing the visual acuity. The declaration 1.0 corresponds to a visual acuity of 100%.