SOME EYE PROBLEMS IN TIBETAN TERRIERS

Cataracts in Tibetan Terriers are basically the same as in humans - the bluish white thickening that you can (eventually) see for yourself, though identifiable at a much earlier stage by a canine ophthalmologist.  Some cataract development is normal, as part of the aging process.  However, there is also a cataract which may occur in a much younger dog (as young as two or three or possibly earlier).  These cataracts are considered hereditary.  Whether to remove them or not is determined on a case-by-case basis as far as I know, with not removing them the more common practice as the dog doesn't usually benefit long-term. 

Please click here for more indebt information on Cataracts, and also here  for yet another article.

Progressive Retinal Atrophy is where the retina of the eye gradually disintegrates.  First the dog will lose his "night vision" and then it will progress to 24 hour blindness as well.  This also is hereditary.  There is no cure and no treatment.  There seems to be two "varieties" of PRA - one that is evident by the time the dog is a couple of years old and one which is a very late onset (and might be missed by the average owner, or even vet, thinking the dog is just losing his/her vision due to old age).  It is hereditary - so far as is known, both parents must be carriers (i.e., both may themselves appear to be fine but carry the genes which "pair up"). 

Please click here for PRA Diagnosis and click here for Screening for Progressive Retinal Atrophy in Tibetan Terriers.

Lens Luxation is where the lens of the eye becomes detached.  The way my ophthalmologist described it (for the dog) is it probably feels like a contact lens, which has become dislodged - extremely uncomfortable and painful.  The "cure" is to remove the lens surgically in an operation that is not unlike cataract surgery though even more delicate.  It also occurs bilaterally - meaning that when one lens goes, the other one will soon follow suit.  The dog looses the ability to switch from "close up" to "long distance" vision - he'll be able to see things up close but not in the distance.  Depending on where the lens fell to, there may also be a resultant secondary glaucoma - which requires eye drops daily for the rest of the dog's life.  Lens Luxation is tricky - it does not occur before the age of three years (which is why I rarely breed my dogs before the age of three) and may occur as late as seven, eight, or nine year old, when a dog may have already produced/sired litters (which is one reason why I like people who buy my pups to keep in touch with me over the years).  Lens Luxation is hereditary.

Please click here for more indebt information on Lens Luxation, and also here for yet another article.
 
The major project at this time that researchers are working on is to find the "marker gene" - i.e. the piece of the DNA that gives the cells the "instructions" to grow in a particular way - for both PRA and Lens Luxation.  Eventually, the idea is that we will be able to draw a blood or tissue sample from a dog before it is bred and see if it carries the DNA "coding" to create PRA or Lens Luxation.  We then can avoid breeding dogs who have these genes and therefore not produce pups with these defects (this is the ideal scenario), or at least avoid breeding two together that both have the piece of genetic coding to potentially match up so that the worst that we would produce would be potential carriers (then all the offspring would have to be tested as well for the next generation).  While the ideal is to eliminate the problem, sometimes the "bad" gene can be tied to something desirable that you would loose along with the undesirable and sometimes there just aren't enough good quality dogs to select from if you eliminate all the carriers. Until this comes into practice in Ireland, all we have to rely on are annual eye tests by a qualified Ophthalmologist.  Important update see News 2006 30th May.

To facilitate breeders in Ireland, I am happy to organise an Eye Testing Clinic every year.  This clinic is conducted by Dr. T. D. Grimes BVetMed PhD DVR DVOpthal DECVO MRCVS.  I arrange for  this clinic to be held at The National Show Centre in Cloghran, as it is considered by most to be an easy venue to reach, and is known to all but the novice breeders.  I promote the testing with a mailing shot well in advance of the date it is to be held, advertise it at shows and training centres, and also make it easy for some, by giving them the opportunity to book on line at this site.  I cannot stress strongly enough the IMPORTANCE OF ANNUAL EYES TESTS if you plan to breed.