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PRIMARY LENS LUXATION AND INTERBREED PROGRAM Miniature bullies suffer with all the same generic illnesses as standard bullies plus primary Lens Luxation (PLL), All is not lost if your dog becomes affected as the use of Xalatan drops is proving successful in saving the sight of our mini's - read on for further information. What is PLL A diagram of the canine eye so that you can understand how it works.
As there are not many ways to write about PLL I have decided to use the information from the Miniature Bull Terrier Club Handbook as this is informative and easy to understand. The lens of the eye is situated behind the iris, the coloured part of the eye. In the condition of luxation (dislocation), the lens breaks away from its retaining attachments within the eye and becomes free. In most cases, the lens passes forward and comes to rest between the cornea and the iris, in the anterior chamber of the eye. In just a few cases, the lens will pass into the posterior part of the eye or will float from one area to the other. The term subluxation is used to denote a lens that has partially, but not completely, broken away from its attachments. Luxation of the lens can be primary or secondary. Secondary cases are those produced by some other problem within the eye, such as cataract or glaucoma. Primary luxation is inherited and is not associated with any other eye problems but results from in-born defects in the structures holding the lens in its normal position within the eye. Glaucoma will result from a lens that is displaced into the front part of the eye if the condition is not treated surgically. Inherited primary lens luxation occurs in several terrier breeds - the Fox Terrier (Smooth), the Fox Terrier (Wire), the Sealyham Terrier, the Jack Russell Terrier and the Tibetan Terrier. It also occurs in the Border Collie and the Miniature Bull Terrier. Either sex may be affected and most cases occur in middle age -3 to 7 years -although there are exceptions to this rule. In a few cases, both eyes are affected at the same time, but it is more usual for there to be an interval of weeks or months, and sometimes even years, between one eye and the other. However, the condition will invariably affect both eyes in due course. If a lens luxates into a forward position it will cause an opacity of the central part of the cornea and will lead to an increase of pressure within the eye -glaucoma -which will cause clouding of the cornea, congestion and pain, ultimately leading to enlargement of the eyeball and total blindness. It is important to recognize the early signs of luxation, for treatment is required urgently in most cases. The signs of subluxation would not be appreciated by the owner, but can be detected by a veterinarian specializing in ophthalmology weeks or even months before actual dislocation of the lens occurs. Regular eye check by a BVA/KC/ISDS Eye Scheme registered veterinary ophthalmologist every 4-6 months may well save your mini bullies sight and even his life because if caught early enough you can quickly administer the Xalatan drops and save your dog a lot of pain and stress. The change from subluxation to luxation can often be dramatic and, once the lens has passed forwards, there may be signs of irritation and discomfort and the eye may have an unusual glossy or bluish appearance. If both eyes are affected simultaneously, visual disturbances will be apparent. In a susceptible breed it is important to consider any eye problem as a potential luxation or subluxation. What might appear to be a simple conjunctivitis may well prove to be early movement of the lens. Any apparent eye inflammation or discomfort should be checked by a veterinary surgeon and, if there is any doubt, referred to a veterinary ophthalmologist. This is especially important if one eye has already been affected by, or lost through, luxation. When a lens has moved forwards, thus likely to result in glaucoma and loss of the eye, removal of the lens from the eye is the only possible treatment. If successful, such an operation will result in the dog having useful guidance vision. Unfortunately, although the success rate of such an operation is reasonable in most terriers, the Miniature Bull Terrier shows particular problems with this type of surgery, due to the narrow eyelid opening and the small, deep-set eye. Where a lens has passed backwards -an unusual occurrence in the M.B.T. -treatment with drugs may well be preferable to surgery. XALATAN drops have proved so far to be very successful in the MBT - Many mini bullies using these drops are having no ill effect to them and have not fully luxated even though they have been on the drops for years. Still today many ophthalmologists insist on operating, be firm and stand your ground and insist on trying the Xalatan drops first. If your dog has only sub luxated and/or the lens has not moved forwards then the drops will prevent the lens from moving forward and thus will avoid painful surgery and the loss of sight or worse of the eye itself. Please read this open letter 'Life after PLL' it is written by a past health co-ordinator of the MBT after one of his dogs went down with PLL. It has vital contact information for excellent advice, or see the MBTC website, or our Tiffy's page on this site. Primary lens luxation in the affected breeds is inherited. Studies in the Tibetan Terrier show that this is a simple recessive inheritance, (Both parents carry a normal gene, and a faulty, recessive, gene . The parents, although carriers, are unaffected by the faulty gene. Their offspring are affected, not affected, or carriers, or a mixture of these) and the same is likely to apply to all affected breeds. Those animals carrying the factor will either be carriers or will become afflicted sooner or later. It is sometimes suggested that a blow to the eye might be responsible for dislocation of the lens. This is very unlikely, but injury might well hasten the onset in a susceptible animal. Again, glaucoma can result in luxation but, in the affected breeds, it would be far more likely that luxation resulted in glaucoma. Under no circumstances should an affected animal be used for breeding, nor should the parents or progeny or littermates, which are likely to be carriers, be used in any future breeding program. Control of the problem lies in the hands of owners and the Club, so that the identity of affected animals is known. It is essential to make this information available so that breeding from affected stock, or those likely to be carriers, can be avoided. F.G. Startup, Ph.D., B.Sc., M.R.C.V.S., D.V.Opthal Taken from The Miniature Bull Terrier Club Handbook. Edited by Mrs. V. Allenden. © The Miniature Bull Terrier Club. (England)
It is vitally important for the sake of the breed that you let the MBTC Health Officer know if your dog has been diagnosed with PLL and that you allow him/her to go on the PLL register, whether you have a pet or a breeding dog/bitch. The register is the best way to help the breed you love so much. There is a form on the club website for you to download and fill in and send to the Health Officer. If you cannot find it then email me for a copy. And please send a DNA sample (by cheek swab) available from the Health Officer or the AHT to help with the ongoing research.
Miniature Bull Terrier Club UK
Interbreed Program The Miniature Bull terrier Club along with the Health council and the Kennel Club are running a program to try and rid PLL from Mini Bullies, the interbreed program works by crossing small fully health tested standards with fully health tested miniatures both must be licensed by the KC and a certificate issued. As both parents need to be carriers and the standards do not suffer with PLL so therefore do not carry PLL this should eliminate PLL from the MBT. The only real problems caused by the interbreeding program is that some of the puppies grow beyond the the 14 inch marker however they are still classed as and KC registered as Miniature and although some can be as tall as a standard they are normally much smaller framed and far lighter than a standard bully. Breeders are working hard to bring the size of the miniature back into the interbreeds, there are some very nice miniatures in the show ring today and hopefully we we soon see all miniatures back to correct height without PLL. More information available from the MBTC link above. FURTHER LINKS OF INTEREST IN PLL AND INTERBREED PROGRAM www.ch-w.demon.co.uk/billy/bullterrier.htm MBTCUK Interbreeding Program
NOTE: INFORMATION SUPPLIED ON THIS PAGE IS FOR INFORMATION PURPOSES ONLY. IF YOU SUSPECT YOUR DOG HAS ANY OF THE ABOVE SYMPTOMS OR PROBLEMS PLEASE SEEK THE ADVICE OF YOUR VET.
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