Corneal lipidosis or lipid deposit in the cornea of rabbits

Esther van Praag, Ph.D.

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Warning: this file contains pictures that may be distressing for people.

Corneal lipidosis - also called corneal dystrophy or lipid keratopathy - is a condition where excess lipids (usually cholesterol esters) or minerals (calcium) are deposited under the surface of the cornea. The infiltration usually starts at the edge of the cornea and can be observed in the anterior stroma, the epithelial basement membrane and the epithelium.

Corneal lipidosis is not associated to a disease; it is not breed or gender dependent.

Etiology

A lipid rich diet and/or trauma are the main causes for lipid deposits into the cornea. Congenital factors cannot be ruled out.

Michel Gruaz

Rabbit presenting a circle opacity at the periphery of the cornea, caracteristic sign of lipid depsits. The disease is called lipid keratopathy or lipidosis f the cornea.

Clinical signs

It is based on a complete ophthalmic examination and a discussion with the owner about the food fed to the rabbit.

Both eyes are usually affected (bilateral) but not necessarily to the same degree. Unilateral lipidosis has rarely been reported. The fat deposits, which usually start near the third eyelid, can be opaque, raised, subtle and pale, bright white, silver or grey colored areas. Vascularization is observed in the affected part of the cornea. While the cornea is mainly affected, fat deposits have also been noted in the lens, iris and ciliary body of a Dutch rabbit. Often it is accompanied by macrophage invasion. An inflammatory process has been observed, but does not always seem to be present.

Unlike in dogs, corneal lipidosis is associated to gradual loss of vision in rabbits. If the deposit is severe, it can lead to ulceration of the cornea.

There is no pain associated to this condition.

Diagnostic and differentiel

A blood test helps confirm the high level of lipids and cholesterol in the blood. The ratio of LDL and HDL corresponds to that present in the eye.

A complete eye examination is necessary to confirm the diagnosis.

A discussion of the rabbit’s diet is necessary and corrections must be immediately implemented.

Corneal lipidosis should be differentiated from:

- Retinal lesions, when loss of vision is observed;

- Neoplasia;

- Uveitis;

- Cerebral lesions, even when these are generally accompanied by further neurologic signs, while the persistant physiological constriction of the pupilla (photomotor reflex or pupillar reflex) is not affected.

https://circ.ahajournals.org/cgi/reprint/18/4/519

Lipid plaque in hypercholesteremic rabbit cornea occurring at site of vascularity. Cornea had been cauterized several times by heated probe.

https://circ.ahajournals.org/cgi/reprint/18/4/519

Sections of rabbit cornea in region of plaque stained with hematoxylin-Sudan. Noteworthy is abundance of intracellular globular lipid and relatively slight amount of granular sudanophilia.

Treatment

There is no medical therapy available, other than bring modification to the diet. Fatty food and milk-based products (cheese, butter, and yogurt) should be discontinued.

It is not known if superficial keratotomy can help.

Acknowledgement

Many thanks to Michel Gruaz (Switzerland) for his great pictures of lipid accumulation in this Rex rabbit and his permission to use on this page.

Further information

Fallon MT, Reinhard MK, DaRif CA, Schoeb TR. Diagnostic exercise: eye lesions in a rabbit. Lab Anim Sci. 1988; 38:612-3.

Garibaldi BA, Goad ME. Lipid keratopathy in the Watanabe (WHHL) rabbit. Vet Pathol. 1988; 25:173-4.

Gwin RM, Gelatt KN. Bilateral ocular lipidosis in a cottontail rabbit fed an all-milk diet. J Am Vet Med Assoc. 1977; 171:887-9.

Hillyer E.V., Quesenberry K.E., Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, New York: WB Saunders Co., 1997, p. 339-345.

Sebesteny A, Sheraidah GA, Trevan DJ, Alexander RA, Ahmed AI. Lipid keratopathy and atheromatosis in an SPF laboratory rabbit colony attributable to diet. Lab Anim. 1985; 19:180-8.

Stock EL, Mendelsohn AD, Lo GG, Ghosh S, O'Grady RB. Lipid keratopathy in rabbits. An animal model system. Arch Ophthalmol. 1985 May;103(5):726-30.

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