Search results
Results from the WOW.Com Content Network
Blepharospasm usually begins with occasional twitches of both eyelids, which progress over time to forceful and frequent spasms and contractions of the eyelids. In severe episodes, the patient cannot open their eyelids (apraxia), which severely limits their daily activities. Prolonged closure of the eyelids may result in functional blindness. [4]
The corneal reflex, also known as the blink reflex or eyelid reflex, [1] is an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body), though it could result from any peripheral stimulus. Stimulation should elicit both a direct and consensual response (response of the opposite eye).
Dalrymple's sign is a widened palpebral (eyelid) opening, or eyelid spasm, seen in thyrotoxicosis (as seen in Graves' disease, exophthalmic goitre and other hyperthyroid conditions), causing abnormal wideness of the palpebral fissure.
A positive test is defined by excessive upward excursion followed by downward drift of the upper eyelid immediately after the eye opens, in similar fashion to Cogan's lid twitch sign. The test is negative if the upper eyelid position remains stable when the eye opens. A positive test is consistent with a diagnosis of OMG.
Ocular ischemic syndrome is the constellation of ocular signs and symptoms secondary to severe, chronic arterial hypoperfusion to the eye. [1] Amaurosis fugax is a form of acute vision loss caused by reduced blood flow to the eye; it may be a warning sign of an impending stroke, as both stroke and retinal artery occlusion can be caused by thromboembolism due to atherosclerosis elsewhere in the ...
Eyeblink conditioning (EBC) is a form of classical conditioning that has been used extensively to study neural structures and mechanisms that underlie learning and memory. The procedure is relatively simple and usually consists of pairing an auditory or visual stimulus (the conditioned stimulus (CS)) with an eyeblink -eliciting unconditioned ...
One example of a pressure phosphene is demonstrated by gently pressing the side of one's eye and observing a colored ring of light on the opposite side, as detailed by Isaac Newton. [ 7 ] [ 8 ] [ 9 ] Another common phosphene is "seeing stars" from a sneeze , laughter, a heavy and deep cough, blowing of the nose , a blow on the head or low blood ...
Abnormal blood vessels can form in the back of the eye of a person with diabetes. These new blood vessels are weaker and prone to breaking and causing hemorrhage. [ 2 ] Diabetic retinopathy accounts for 31.5–54% of all cases of vitreous hemorrhage in adults in the United States.