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Abstract
Displacement of the crystalline lens from its normal position, which is known as ectopia lentis, can cause many visual disturbances according to the amount of displacement. Ectopia lentis may be hereditary or acquired. Disruption or dysfunction of the zonular fibers of the lens, regardless of the cause (acquired or heritable condition), is the underlying pathophysiology of ectopia lentis. Acquired displacements of the lens are slightly more common than the hereditary varieties and are related to mechanical stretching of the zonule, this includes: trauma (more than 50% of all lens displacements), a large eye (i.e. high myopia, buphthalmos), anterior uveal tumors, and hypermature cataract. Hereditary causes may be without systemic association as in familial ectopia lentis, ectopia lentis et pupillae, and aniridia, or with systemic association as in Marfan syndrome, homocystinuria, Weill-Marchesani syndrome and other miscellaneous conditions. The common presenting symptoms of ectopia lentis are: decreased distance visual acuity (secondary to astigmatism or myopia), poor near vision (loss of accommodative power) and monocular diplopia. The critical signs for diagnosis include decentered or displaced lens, iridodonesis and phacodonesis. The main complication of ectopia lentis are: meridional amblyopia, glaucoma and rarely, lens-induced uveitis. The management for ectopia lentis should be tailored for every case. Spectacle or contact lenses correction may correct myopia and/or astigmatism induced by lens tilt or edge effect in eyes with mild subluxation. Aphakic correction may also afford good visual results if a significant portion of the visual axis is aphakic in the undilated state.