nærforstørrelse

Nærforstørrelse, also known as accommodation, is the process by which the eye changes its focus from distant to near objects. This ability is crucial for clear vision at close range and is achieved through the action of the ciliary muscle and the lens within the eye. When viewing distant objects, the ciliary muscle is relaxed, causing the lens to be flatter and thinner, thus having a lower refractive power. To see near objects, the ciliary muscle contracts, which in turn loosens the suspensory ligaments that hold the lens. This relaxation allows the elastic lens to become thicker and more convex, increasing its refractive power and enabling the eye to focus the light from the near object onto the retina.

The range of near vision, or the amplitude of accommodation, diminishes with age. This age-related decline in the eye's ability to focus on near objects is called presbyopia. Presbyopia typically begins to manifest in individuals around the age of forty, leading to difficulty reading small print or performing other close-up tasks. Factors such as the hardening of the lens and weakening of the ciliary muscle contribute to this phenomenon. While presbyopia is a natural part of aging, its effects can be corrected with reading glasses, bifocals, or multifocal contact lenses, which provide the necessary additional refractive power to compensate for the loss of natural accommodation.