Diktyoma mitotic activity, sarcomatous components, or invasion into the uvea, cornea, or sclera. Most diktyomas are malignant. The most common symptoms of diktyoma are vision loss and pain, while the most common signs are leukocoria and presence of a mass in the iris or ciliary body. Other signs and symptoms include lens subluxation, glaucoma, cataract, exophthalmos, buphthalmos, strabismus, and ptosis. Imaging studies such as ultrasonography (US), Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) may aid diagnosis. On ultrasound, diktyomas typically appear as echogenic, irregularly shaped to ovoid masses. Ultrasound is excellent for demonstrating cystic collections of vitreous fluid in the
Sperm whale It is the largest among the toothed whales, weighing about 170 g. It is overall ellipsoid in shape, compressed along the visual axis, measuring about 7×7×3 cm. The cornea is elliptical and the lens is spherical. The sclera is very hard and thick, roughly 1 cm anteriorly and 3 cm posteriorly. There are no ciliary muscles. The choroid is very thick and contains a fibrous "tapetum lucidum". Like other toothed whales, the sperm whale can retract and protrude its eyes thanks to a 2-cm-thick retractor muscle attached around the eye at the equator, but are unable to roll the eyes