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Tadpole pupil is diagnosed and characterized by the abnormality of the pupil shape. The pupil can disorient itself in different ways before it returns to its original shape. [6] For example, the pupil may stretch out to a 7 o'clock position, [6] i.e. the pupil points in the same direction the hour hand on a clock would at 7 o'clock.
Colobomas in the iris can make a keyhole or teardrop shape, the NEI points out. What causes coloboma? Coloboma is something that happens before a baby is born. The eye develops in utero during the ...
A coloboma (from the Greek κολόβωμα, meaning "defect") [1] is a hole in one of the structures of the eye, such as the iris, retina, choroid, or optic disc.The hole is present from birth and can be caused when a gap called the choroid fissure, which is present during early stages of prenatal development, fails to close up completely before a child is born.
The eccentricity effect is a visual phenomenon that affects visual search.As retinal eccentricity increases (i.e. the light of the image enters the eye at a larger angle and approaches peripheral vision), the observer is slower and less accurate to detect an item they are searching for.
Dilation and constriction of the pupil. Pupillary response is a physiological response that varies the size of the pupil, via the optic and oculomotor cranial nerve.. A constriction response (), [1] is the narrowing of the pupil, which may be caused by scleral buckles or drugs such as opiates/opioids or anti-hypertension medications.
The extraneous pupil is c. 2.5mm away from the principal pupil. In cases of true polycoria there is an intact sphincter muscle , which contracts and dilates the pupils. [ 5 ] In an eye without polycoria, the sphincter muscle is a part of the iris that functions to constrict and dilate the pupil.
The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. [1] It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil.
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