ASTIGMATOMETER Meaning and
Definition
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An astigmatometer is a specialized ophthalmic instrument used by optometrists and ophthalmologists to measure and diagnose astigmatism in individuals. Astigmatism refers to an irregular curvature of the cornea or lens of the eye, which results in blurred or distorted vision. This condition occurs when the cornea or lens has a more oval shape rather than a round shape, causing light to focus on multiple points rather than a single point on the retina.
The astigmatometer helps eye care professionals determine the severity of astigmatism by measuring the irregularities in the curvature of the eye's surface. It typically consists of a series of rotating discs or images that the patient is asked to focus on. By analyzing the patient's ability to discern clear images or lines in various orientations, the astigmatometer can accurately determine the degree and axis of astigmatism present.
Through this examination, the optometrist or ophthalmologist can prescribe corrective measures such as glasses, contact lenses, or refractive surgery to counteract the effects of astigmatism and improve the patient's vision. The astigmatometer is an essential tool in the diagnosis and management of astigmatism, aiding in the selection of appropriate vision correction options tailored to each individual's specific needs.
Etymology of ASTIGMATOMETER
The word "Astigmatometer" is composed of two elements: "astigmat-" and "-meter".
1. "Astigmat-" comes from the medical term "astigmatism", which refers to a common eye condition causing blurred or distorted vision due to an irregularly shaped cornea or lens. The term "astigmatism" originated from the Greek word "astigma" (ἀστίγμα), meaning "a point". In the 19th century, the French physicist and optician Augustin-Jean Fresnel popularized the use of the term to describe this visual defect.
2. "-Meter" is a combining form derived from the Greek word "metron" (μέτρον), meaning "measure". It is widely used in English to indicate an instrument or device for measuring a specific thing or property.
