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Editor,—We describe a new ultrasonographic sign dubbed “ vitreous basket sign” (looks like a basketball caught at the bottom of a basket) found in eyes with posteriorly dislocated lenses. Identifying this pattern can contribute to the diagnosis and differential diagnosis of dislocated lens.
We used the Acuson 128x p/o linear array 7 MHz probe instrument.
The patient was 65 years old white woman with a painful traumatic blind eye and a large leucoma adherens. Ultrasonographic examination demonstrated a hyperechogenic mass on the retina at the posterior pole, with a posteriorly dragged anterior vitreous face, creating a hypoechogenic central tunnel (Fig 1A). The mass and tunnel changed location with ocular movements.
A similar ultrasonographic pattern has been seen in seven eyes of six patients. Dislocated lens or nucleus should always be in the differential diagnosis of an intraocular mass. Alwardet al 1 described three cases of pseudophakic patients with dropped nuclei during extracapsular cataract extraction suspected to be choroidal melanomas later.
There are several ultrasonographic signs cited as characteristic of dislocated lenses2: a hyperechogenic mass with an oval shape, which can become highly reflective as cataract develops, and vitreal strands adherent to the mass which is mobile and changes location with eye movements.
We believe this particular ultrasonographic sign can be ascribed to the following process. The lens detaches, encounters the anterior vitreous face, and pushes it posteriorly by its weight towards the retina. The anterior vitreous face, vitreous gel, and collagen fibres within the vitreous are pushed back by the lens creating the wall of an aqueous filled tunnel with the lens at its bottom (Fig 1B).
In most cases this sign is easy to demonstrate, and we recommend it as a useful new clue to the ultrasonographic diagnosis of dislocation of the lens.