Transient monocular blindness caused by vasospasm

Article Abstract:

Amaurosis fugax is transient blindness in one eye. An episode of blindness may last a few seconds or a few minutes. Over a hundred years ago, physicians had already surmised correctly that the condition is caused by ischemia. That is, the blood supply of the retina in the eye is temporarily disrupted, momentarily cutting off the supply of oxygen. However, physicians were unsure of the cause of the disruption of blood flow. Some favored the embolic hypothesis. According to this idea, the blood supply is temporarily disrupted by a tiny clot formed of the blood protein fibrin. The first direct observation of such clots in 1959 did much to strengthen this hypothesis. However, this observation did not mean that all cases of amaurosis fugax result from the same cause. Two cases are presented in which transient blindness in one eye was observed to be the result of vasospasm, or the spasmodic contraction of blood vessels in the retina which temporarily disrupts the flow of blood. In addition to these cases, three other cases were also observed in which vasospasm was implicated. In all five cases, the patients had several episodes of monocular blindness each day prior to examination. In one case, the patient experienced 30 episodes of one-eye blindness each day. Direct examination of the eyes revealed no evidence of emboli (often caused by clotted tissue blocking the circulation). However, photographs of the retina before, during, and after attacks of amaurosis fugax revealed constriction of the arteries and veins in the affected eye. In one patient, constriction of retinal veins was seen to persist even after recovery from the momentary blindness. All five patients had a favorable outcome; the amaurosis fugax resolved and has not recurred in follow-up. (Consumer Summary produced by Reliance Medical Information, Inc.)

Case studies, Blood vessels, Retina, Eye, Cerebral ischemia, Amaurosis fugax, Retinal vessels

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Lack of efficacy of light reduction in preventing retinopathy of prematurity

Article Abstract:

Reducing premature infants' exposure to light does not appear to reduce the frequency of retinopathy of prematurity. This disease of the retina in premature infants can lead to blindness. Researchers put goggles on 188 premature infants to reduce the amount of light reaching their eyes and compared their outcome to 173 infants who did not wear goggles. The goggles reduced visible light exposure by 97% and ultraviolet light by 100%. About one month later, 54% of the infants wearing goggles and 58% of those not wearing goggles had developed retinopathy of prematurity.

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Preventing blindness in premature infants

Article Abstract:

More research is needed to determine the most effective way to prevent retinopathy of prematurity. This retinal disease affects many premature infants and can lead to blindness if not treated. Cryotherapy using cold temperatures can be useful, but it has been replaced by laser photocoagulation. However, even after treatment, many infants can develop a detached retina. Prevention seems to be the best goal, but a 1998 study found that reducing light exposure does not appear to reduce the incidence of the disease.

Editorial, Diseases, Infants (Premature), Premature infants

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