The Eyes – Health, Diseases, Information and Function

Eyes The eyes conduct the function of vision. Practitioners who provide care for the eyes and vision may be ophthalmologists (medical doctors who specialize in ophthalmology, providing medical and surgical treatment for diseases of the eye) or optometrists (doctors of optometry who specialize in diagnosing and correcting refractive errors of vision). Functions of the Eye […]

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Cornea of Eye – Transparent Portion of The Sclera

Definition of Cornea Cornea – the transparent portion of the sclera, the eye’s outer layer. The cornea functions as a window to allow light to enter the eye and is the first point of refraction (bending lightwaves to focus them on the retina). Irregularities in the surface of the cornea can distort refraction, resulting in astigmatism. Though the […]

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Eye (human) – Definition and Function of The Eyes

Function of the Eyes Eye is the organ of vision. The paired eyes work in coordination to present nerve impulses the brain interprets as dimensional (stereovisual) images. The function of sight requires close integration among the structures of the eye, the neurologic system, and the muscular system. Each eye is a fluidfilled, elongated globe of […]

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Floaters – Fragments of Inner Eye Material

Floaters Definition Fragments of inner eye material that float through the vitreous humor, casting shadows against the retina as entering light strikes them. Floaters may take various shapes and sizes, and typically move around the visual field, changing position with blinking or eye movement. Most are harmless, though large fragments may interfere with vision. Holding the eye still may allow the […]

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Intraocular Pressure – Causes and Definition

Definition of Intraocular Pressure Intraocular Pressure – the pressure within the eye that maintains the eye’s form and structure. Normal intraocular pressure in an adult is 12 to 22 millimeters of mercury (mm Hg). A device called a tonometer measures intraocular pressure, either through light contact against the anesthetized eye or via the force of resistance to […]

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Lens of The Eye – Definition

Definition The primary focusing structure of the eye, located in the center at the front of the eye. The lens is transparent, convex (rounded outward on each side), round, and flexible. A thin membrane encloses the lens. Tiny muscles at the front edges of its sides, the ciliary muscles, contract to flatten the lens and relax to […]

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Optic Nerve eye – Definition and Function

Optic Nerve Definition Optic Nerve – the second cranial nerve, which conveys nerve impulses from the eye to the brain. There are two optic nerves, one from each eye. The fibers that become the optic nerve originate in the occipital lobes of the cerebrum, in an area called the visual cortex. Each extends along structures called the optic […]

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Retina – Definition, Function and Diseases

Retina – Definition and Function Retina – the innermost layer of the eye. The retina receives light images and converts them to nerve impulses the optic nerve conveys to the brain. The retina is two tissue-thin layers that together are less than 1⁄2 millimeter in thickness. The outer pigment layer provides a completely light-absorbing, nonreflective lining. The […]

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Scotoma – Definition and Information

Definition of Scotoma An area of the retina in which there are few or no cones or rods, the specialized nervecells that convert light signals to nerve impulses, creating a blind spot in the visual field. Scotomas may represent healed injuries to the retina such as retinal tears or degeneration of the retina such as may occur with age-related macular […]

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Visual Field – definition and tests

Definition of Visual Field Visual Field is the total area or scope of vision. eye care specialists map the visual field by measuring the boundaries of peripheral vision in degrees from the point of central vision. A normal field of vision is 135 degrees vertically (60 degrees up and 75 degrees down) and 160 degrees horizontally (100 […]

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