Human eyes are sense organs used for vision. Perception of light is enabled by cone and rod cells contained in the retina. These cells also allow for differentiation of color, perception of depth and vision. Human eyes have the ability to differentiate more than ten million different colors. To understand more about the eye, San Antonio is a good place to visit. San Antonio eye specialists are well specialized and qualified to provide all forms of care for eyes.
Eyes are not shaped like perfect spheres, rather, they are composed of two pieces fused together. The cornea forms the frontal part. It is transparent in color and appears curved and links to the bigger part referred to as the sclera. The radius of the cornea typically measures 8 millimeters while the sclera measures 12 mm in radius. The limbus ring connects the sclera and cornea. The pupil is surrounded by the iris.
Pupils are adjusted by the dilator and sphincter muscles located in the iris. Light admission into the eyes is done through the cornea. When the light reaches light-sensitive cells of the retina, it is converted into electrical signals before being sent to the brain by optic nerves. The brain takes up the electrical signals and processes them into images. The retina is responsible for conversion of light into signals.
The eye sizes of adults have been known to vary in size from each by one or two millimeters. This observation is consistent across all ethnicities in the world over. Vertical, horizontal, and sagittal measurements vary without any observable differences based on gender and age group. Eyes grow rapidly from birth up to the age of three years. Full size is achieved at the age of thirteen years.
The make-up of the eye consists of three coats enclosing three other transparent structures. The name fibrous tunic is used to refer to the outermost coat. Composition of the fibrous tunic is cornea and sclera. Vascular tunic is the named given to the middle layer. Choroid, ciliary body, and iris make up the vascular layer. The innermost layer is called retina. These layers can be observed through a device called an ophthalmoscope.
Inside those coats are aqueous humour, the vitreous body, and flexible lens. Aqueous humour occurs in the posterior and anterior chamber. The anterior chamber is placed between iris and cornea whereas the space between iris and lens holds the posterior chamber. Suspension of the lens is done by suspensory ligament. Vitreous body is placed behind lens.
The movement of the eyes is done by six muscles. These muscles are superior rectus, superior oblique, medial rectus, inferior oblique, lateral rectus, and medial rectus. These muscles exert a torque on the globe which causes it to move in pure rotation. The translation that occurs is about one millimeter.
Eyes suffer from a large number of conditions which are caused by different causes such as disease, age, and disorder. Aging causes some changes in eyes, which result in certain medical conditions. Some conditions occur in newborns without external causes. There are many types of eye specialists including opticians, optometrists, and ophthalmologists.
Eyes are not shaped like perfect spheres, rather, they are composed of two pieces fused together. The cornea forms the frontal part. It is transparent in color and appears curved and links to the bigger part referred to as the sclera. The radius of the cornea typically measures 8 millimeters while the sclera measures 12 mm in radius. The limbus ring connects the sclera and cornea. The pupil is surrounded by the iris.
Pupils are adjusted by the dilator and sphincter muscles located in the iris. Light admission into the eyes is done through the cornea. When the light reaches light-sensitive cells of the retina, it is converted into electrical signals before being sent to the brain by optic nerves. The brain takes up the electrical signals and processes them into images. The retina is responsible for conversion of light into signals.
The eye sizes of adults have been known to vary in size from each by one or two millimeters. This observation is consistent across all ethnicities in the world over. Vertical, horizontal, and sagittal measurements vary without any observable differences based on gender and age group. Eyes grow rapidly from birth up to the age of three years. Full size is achieved at the age of thirteen years.
The make-up of the eye consists of three coats enclosing three other transparent structures. The name fibrous tunic is used to refer to the outermost coat. Composition of the fibrous tunic is cornea and sclera. Vascular tunic is the named given to the middle layer. Choroid, ciliary body, and iris make up the vascular layer. The innermost layer is called retina. These layers can be observed through a device called an ophthalmoscope.
Inside those coats are aqueous humour, the vitreous body, and flexible lens. Aqueous humour occurs in the posterior and anterior chamber. The anterior chamber is placed between iris and cornea whereas the space between iris and lens holds the posterior chamber. Suspension of the lens is done by suspensory ligament. Vitreous body is placed behind lens.
The movement of the eyes is done by six muscles. These muscles are superior rectus, superior oblique, medial rectus, inferior oblique, lateral rectus, and medial rectus. These muscles exert a torque on the globe which causes it to move in pure rotation. The translation that occurs is about one millimeter.
Eyes suffer from a large number of conditions which are caused by different causes such as disease, age, and disorder. Aging causes some changes in eyes, which result in certain medical conditions. Some conditions occur in newborns without external causes. There are many types of eye specialists including opticians, optometrists, and ophthalmologists.
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