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THE "NIGHT-BLINDNESS TEST"

An Aid In Detecting PRA

Update of the previous article : Home Testing for PRA

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BACK TO THE ARTICLE : FACTS ABOUT PROGRESSIVE RETINAL ATROPHY ( PRA )

 

A feasible way for most everyone to check for the possibility of Progressive Retinal Atrophy in their

Papillons is a method referred to as "night-blindness test".

  

The properly done electroretinograph is the most definitive method of detecting retinal deficiencies but

a "night-blindness test" will give you an indication of a problem long before an ophthalmoscopic

examination will find signs of disease.

 

I have begun to use this test on my puppies prior to ERG to prove the correlation.  I suggest it to be

performed at 12, 14, and 16 weeks.

 

WE use 2 flashlights using “D” batteries. ( make sure that the batteries are new )  Two thicknesses of

red tissue paper are held in place over the light with a rubber band.  The flashlights are placed at least

5 feet above the floor directing the beam of light to opposite corners of the ceiling.

 

 

The room must be totally darkened … it’s necessary to cover the windows. The flashlights should give

just enough light so that you can observe the dog ( a normal-eyed dog can see well in red light )

therefore, give your eyes time to adjust to the dim light, before proceeding with the test.

 

Prior to turning off the regular lightning,

set-up an obstruction in the center of the room, such as ;

 

~ 2 chairs placed on their sides,

~ a grooming table on its side,

~ 2 waste baskets side by side, or a large carton

 

 

Crate the dog to be tested in a corner of the room.

 

One person will release the dog about 6 feet in front of the obstruction while another person ( well known

by the dog )  calls the dog from behind it.  My experience has been that a normal-eyes dog will around

the obstruction.  Animals affected with a moderate loss of sight will walk up to the obstruction and then

walk around it, while a severely affected dog will walk into the obstruction, usually bumping it solidly.

  

Young puppies ( 12 to 16 weeks ) tend to inquisitive and if they are normal-eyed  will boldly walk up to

the obstruction and check it out, before going around.  They will also, move about the room seemingly

unaware of the lack of the light. Affected pups prefer to remain where you placed them.  One puppy did

come to me after I stepped to the side of the obstruction, continentally talking to her … she crawled into

my feet and sat there crying.

  

The size and color of the testing area will determine the amount of light needed to observe the dogs

behavior, therefore it may be necessary to add more or larger flashlights.  Naturally, a light colored

ceiling will reflect the light more readily than a dark ceiling.

  

All humans present must remain in front of the or directly behind the obstruction, not beside it. 

The obstruction can vary in width from 18 inches to 3 feet with at least 2 feet of space on each side. 

Be awe that the dog is not following a wall.

  

You must be be sure that the dog being tested will respond in a positive manner to the person calling him.

No other words, the dog must know and like the person calling and know how to respond to the word

or words used, such as “come”.

  

Also you may wonder if you are using the proper procedure but, after going through it several times you

will gain confidence.  Do not take the dogs personality into consideration  when you judge the results ...

there is no such room for rationalization.  Instead, have the dogs with inadequate performances

examined by an ophthalmologist and a “proper” ERG , if possible.

 

BACK TO THE ARTICLE : FACTS ABOUT PROGRESSIVE RETINAL ATROPHY ( PRA )

  

  

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