Search results
Results from the WOW.Com Content Network
When the pupil takes on the shape of a tadpole, the condition is called tadpole pupil. Tadpole pupil, also known as episodic segmental iris mydriasis, is an ocular condition where the muscles of the iris begin to spasm, causing the elongation, or lengthening, of parts of the iris. [ 1 ]
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.
Prince Rupert's drops have remained a scientific curiosity for nearly 400 years due to two unusual mechanical properties: [4] when the tail is snipped, the drop disintegrates explosively into powder, whereas the bulbous head can withstand compressive forces of up to 664,300 newtons (67,740 kg f).
Some skates and rays have crescent shaped pupils, [17] gecko pupils range from circular, to a slit, to a series of pinholes, [18] and the cuttlefish pupil is a smoothly curving W shape. Although human pupils are normally circular, abnormalities like colobomas can result in unusual pupil shapes, such as teardrop, keyhole or oval pupil shapes ...
A mydriatic pupil will remain excessively large even in a bright environment. The excitation of the radial fibres of the iris which increases the pupillary aperture is referred to as a mydriasis. More generally, mydriasis also refers to the natural dilation of pupils, for instance in low light conditions or under sympathetic stimulation.
Few people have spent time gazing into a sheep’s eyes, but if you have, you may have noticed something very strange about their pupils. Instead of being round, as is the case with humans, they ...
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.
It can be seen by shining the beam of a small bright light through the pupil from the periphery of a subject's vision. This results in an image of the light being focused on the periphery of the retina. Light from this spot then casts shadows of the blood vessels (which lie on top of the retina) onto unadapted portions of the retina.