Search results
Results From The WOW.Com Content Network
Microphthalmia is a congenital disorder in which the globe of the eye is unusually small and structurally disorganized. [2] [4] While the axis of an adult human eye has an average length of about 23.8 mm (0.94 in), a diagnosis of microphthalmia generally corresponds to an axial length below 21 mm (0.83 in) in adults.
A constriction response , [2] is the narrowing of the pupil, which may be caused by scleral buckles or drugs such as opiates/opioids or anti-hypertension medications. Constriction of the pupil occurs when the circular muscle , controlled by the parasympathetic nervous system (PSNS), contracts, and also to an extent when the radial muscle relaxes.
Top view of Australopithecus africanus skull with post-orbital constriction (left) and modern human skull without (right) In physical anthropology , post-orbital constriction is the narrowing of the cranium (skull) just behind the eye sockets (the orbits, hence the name) found in most non-human primates and early hominins.
The fissure may be increased in vertical height in Graves' disease, which is manifested as Dalrymple's sign.It is seen in disorders such as cri-du-chat syndrome. In animal studies using four times the therapeutic concentration of the ophthalmic solution latanoprost, the size of the palpebral fissure can be increased.
Other common symptoms include lack of an eyelid fold, an appearance of widely spaced eyes (telecanthus), low nose bridge and ear malformations (including cupping and incomplete development). Rare symptoms include microphthalmos (abnormally small eyes), tear ducts in the wrong location and a high-arched palate . [ 1 ]
The pupil of the human eye can range in size from 2 mm to over 8 mm to adapt to the environment. The human eye can detect a luminance from 10 −6 cd/m 2, or one millionth (0.000001) of a candela per square meter to 10 8 cd/m 2 or one hundred million (100,000,000) candelas per square meter.
Micropsia is a condition affecting human visual perception in which objects are perceived to be smaller than they actually are. Micropsia can be caused by optical factors (such as wearing glasses), by distortion of images in the eye (such as optically, via swelling of the cornea or from changes in the shape of the retina such as from retinal edema, macular degeneration, or central serous ...
PEX has been known to cause a weakening of structures within the eye which help hold the eye's lens in place, called lens zonules. [2] The literature recognizes pseudoexfoliation syndrome as a risk factor in cataract surgery. A review based on 999 eyes with pseudoexfoliation reported 156 intra- or postoperative incidents.