EQUINE VETERINARY EDUCATION / AE / MAY 2015


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Fig 4: Dorsal T2-weighted image presenting a hyperintense pocket on the surface of the right cornea (arrow).


Fig 6: Ciliary processes of the left eye. The ciliary cysts (asterisks) are lined, from the inside to the outside, by a layer of nonpigmented epithelium, a layer of pigmented epithelium and stroma. Formalin-fixed, haematoxylin and eosin-stained tissue. (Scale bar represents 50 m.)


Fig 5: Macroscopic picture of the right eye taken during necropsy. A markedly protruding cornea is present (‘cornea globosa’).


Histology of the eyes revealed multiple ciliary cysts that


were more numerous and larger in the right eye than in the left eye. The cysts were lined by nonpigmented epithelium on the inside, which in its turn was surrounded by pigmented ciliary epithelium and a small amount of stroma or a nonpigmented layer of squamous cells (Fig 6). There was diffuse, bilateral retinal atrophy, characterised by blending and atrophy of the inner and outer nuclear layer, occasional focal hypertrophy of the retinal pigment epithelium, and frequent vacuolation and swelling (degeneration) of the ganglion cells (Fig 7). Multifocally, there was absence of the rods and cones layer and also multifocally, there were small areas of retinal detachment. The lenses of both eyes appeared normal. In both eyes, the corneas showed rarefaction of the stroma with the presence of empty clefts between the stromal fibres (oedema) and the presence of small capillaries in the superficial stroma (neovascularisation). In the right cornea, a


Fig 7: Retina of the left eye. There is general disorganisation of the retinal layers with multifocal blending and atrophy of the internal and external nuclear layer (arrows) and even loss of the rods and cones layer (arrowheads). The ganglion cells appear vacuolated and swollen (degeneration). (Scalebar represents 50 m.)


focal epithelial defect (superficial ulceration) was present and there was diffuse, mild infiltration of neutrophils in the superficial stroma, mild perivascular infiltration of plasma cells and lymphocytes at the periphery of the cornea, neovascularisation of the deep stroma and focal adherence of a low to moderate amount of neutrophils and some macrophages to the peripheral corneal endothelium.


Discussion


This case report is in agreement with previous studies stating the high diagnostic value of a combined ophthalmoscopic and ultrasonographic evaluation for reaching the diagnosis of multiple congenital ocular anomalies. To our knowledge, this is the first report of MRI of this particular condition.


© 2015 EVJ Ltd


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