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Deprivation Amblyopia: This occurs when something obstructs light from entering the eye, preventing proper vision development. A congenital cataract is an example of such a condition. Strabismic Amblyopia: The most common form, this type arises when the eyes are not properly aligned, leading to double vision. To avoid confusion, the brain ...
Anisometropia causes some people to have mild vision problems, or occasionally more serious symptoms like alternating vision or frequent squinting. However, since most people do not show any clear symptoms, the condition usually is found during a routine eye exam. [8] For early detection in preverbal children, photoscreening can be used.
Notably, hippos in antiquity referred to involuntary eye movements which are nowadays called nystagmus. [4] It is particularly noticeable when pupil function is tested with a light, [2] but is independent of eye movements or changes in illumination. [1] It is usually normal, however pathological hippus can occur. [2] [3]
Anisocoria is a common condition, defined by a difference of 0.4 mm or more between the sizes of the pupils of the eyes. [2] Anisocoria has various causes: [3] Physiological anisocoria: About 20% of population has a slight difference in pupil size which is known as physiological anisocoria.
Light entering the eye strikes three different photoreceptors in the retina: the familiar rods and cones used in image forming and the more newly discovered photosensitive ganglion cells. The ganglion cells give information about ambient light levels, and react sluggishly compared to the rods and cones.
Normally, as part of the pupillary light reflex, the pupil dilates in the dark and constricts in the light to respectively improve vividity at night and to protect the retina from sunlight damage during the day. A mydriatic pupil will remain excessively large even in a bright environment. The excitation of the radial fibres of the iris which ...
The basic light-processing unit of eyes is the photoreceptor cell, a specialized cell containing two types of molecules bound to each other and located in a membrane: the opsin, a light-sensitive protein; and a chromophore, the pigment that absorbs light. Groups of such cells are termed "eyespots", and have evolved independently somewhere ...
Emmetropia is the state of vision in which a faraway object at infinity is in sharp focus with the ciliary muscle [1] in a relaxed state. That condition of the normal eye is achieved when the refractive power of the cornea and eye lens and the axial length of the eye balance out, which focuses rays exactly on the retina, resulting in perfectly sharp distance vision.