Congenital or
juvenile cataract in a rabbit
Esther van Praag, Ph.D.
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. Thank you also to Dani Tomlin for her help.
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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