Congenital or
juvenile cataract in a rabbit
Esther van Praag, Ph.D.
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Warning: this file
contains pictures that may be distressing for people.
The word cataract comes from the Latin “cataracta”, or from
the Greek katarraktēs, meaning waterfall. It refers to a decrease of the
transparency of the eye lens, which can be partial or affect the whole lens.
Consequently, a reduced amount of light passes through the lens. The ability
to focus and clarity of eyesight will decrease with time. This is accompanied
by a loss of sensitivity to contrast. The ability to see objects is little
affected when light is intense and the lens is only partially affected, but
can lead to full blindness when the opacity of the lens is total and affecting
both eyes.
In rabbits, the
onset of cataract is linked to several causes such as age, eye trauma,
metabolic disorders or a toxic action, or is related to the presence of the
protozoan parasite Encephalitozoon cuniculi (click here for more details). In
young rabbits, the onset of cataract has often a congenital origin. Two types
of inheritance have been observed:
·
Simple recessive inheritance. The young rabbits
presented a slight opacity of the posterior face of the lens. The opacity
gradually increased and was total at the age of 5 to 9 weeks. Interestingly,
progression of the disease was slower in animals fed a dry diet, compared to
those fed a diet rich in water (e.g., fresh vegetables).
·
Incomplete dominant inheritance, with a penetration
of 40 to 60%. This type of cataract develops only in one eye.
Unfortunately, there is only little information available on this
disorder affecting young rabbits.
In young rabbits aged 29 days and 6 weeks:
In a 6 week old rabbit: bilateral juvenile cataract (both eyes are
affected):
Juvenile cataract affecting a few months old rabbit, Harlequin
(Japanese) breed:
Treatment
There is no treatment for cataract in rabbits
Acknowledgements
Thank you to Dr. Flavien Beuchat (Clinique
Vétérinaire du Vieux-Château, Switzerland), to his father Mario Beuchat, and
to Michel Gruaz (Switzerland) for sharing their pictures and their permission
to use here.
Further information
Ehling U. Untersuchungen zur kausalen Genese
erblicher Katarakte beim Kaninchen. Z. Konstitutionsl. 1957;
34, 77-104.
Gelatt KN. Congenital
cataracts in a litter of rabbits. J Am Vet Med Assoc. 1975; 167:598-9.
Nachtsheim H, Gurich H. Erbleiden des
Kaninchenauges. I. Erbliche. Nahtbandchentrubung der Linse mit nachfolgendem
Kernstar. Z. Menschl. Vereb.
Konstitutionsl. 1939; 23, 463-483.
Munger RJ, Langevin N, Podval
J. Spontaneous cataracts in laboratory rabbits. Vet Ophthalmol.
2002 Sep;5(3):177-81.
Weisse I, Niggeschulze A, Stotzer H.
Spontaneous congenital cataracts in rats, mice, and rabbits. Arch Toxicol. 1974; 32:199-207.
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