| lens pits | The paired depressions formed in the superficial ectoderm of the embryonic head as the lens placodes sink in toward the optic cup; the external openings of the pit's are closed as the lens vesicles are formed. (05 Mar 2000) |
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| lens placodes | Paired ectodermal placode's that become invaginated to form the embryonic lens vesicles. Synonym: optic placodes. (05 Mar 2000) |
| lens, simple | <microscopy> A glass disk ground and polished with a spherical figure on one side and a plano, concave, or convex configuration on the other side. (05 Aug 1998) |
| lens stars | Congenital cataracts with opacities along the suture lines of the lens; may be anterior or posterior or both. (05 Mar 2000) |
| lens subluxation | Incomplete rupture of the zonule with the displaced lens remaining behind the pupil. In dislocation, or complete rupture, the lens is displaced forward into the anterior chamber or backward into the vitreous body. When congenital, this condition is known as ectopia lentis. (12 Dec 1998) |
| lens sutures | 9 to 12 faint lines on the anterior and posterior surfaces of the lens that radiate from the poles toward the equator; they mark the lines along which the ends of lens fibres abut. Synonym: lens stars, lens sutures. (05 Mar 2000) |
| lens vesicle | In the embryo, the ectodermal invagination that forms opposite the optic cup; it is the primordium of the lens of the eye. Synonym: lenticular vesicle. (05 Mar 2000) |
| lighthouse lens | <physics> A lens built up, progressively, in zones or steps, each zone with its own individual radius. Considerable spherical correction is attained, and the weight of the lens is greatly reduced. Fresnel lenses were originally designed for lighthouses but they are now attainable for small spotlights, automobile headlights, and similar uses. (05 Aug 1998) |