Perhaps the most important sense to us is sight. That goes for animals too, but in some cases they have other well developed abilities which make up for any deficit. Just like us, animals get old and have difficulty in focusing, many get cataracts or receive injuries which can blind. Of more significance though, are the eye conditions of an inherited nature (those which are passed down from parents to young). Complete blindness from birth or developing in young adulthood can make getting about and finding food a bit difficult, however well-tuned their noses and ears are. It is for these reasons that a scheme was developed by the British Vet. Association (BVA) the Kennel Club (KC) and the International Sheep Dog Society (ISDS) in an attempt to find those dogs affected by recognized inherited eye disease which should not be bred from.

Unfortunately for dogs there are many inherited eye diseases from which they may suffer. Some cause only minor problems such as discomfort or distorted vision, while others lead to progressive blindness, severe and sudden sight loss or pain. To make matters worse, these conditions go by long and strange sounding names. Before discussing some of these inherited eye diseases a little basic anatomy will help draw a clearer picture. Then by passing through how these bits work and on to how dogs are affected we can tie all the information together.

Structure and Function.

The eyeball is a remarkable thing. It starts life as a piece of brain, borrows a bit of skin to make the lids and the 'window' of the eye, called the cornea, turns itself inside out and in dogs is ready to see things within 11 weeks of conception. Now, that's magic!
    We all know what the eye lids do. They protect the eye and sweep tears over the cornea to stop it drying out. The cornea is an extension of the sclera (the white part of the eye) but with perfectly arranged cells so that light travels through unhindered. If we follow this imaginary shaft of light deeper into the eye, it travels through liquid, the aqueous humour, to the lens. The lens focuses the light, or more correctly, the image, onto the retina where everything really happens. All the other eye ball structures have but one purpose ~ to get that light beam to the retina in as perfect a form as is possible and continuously. So, just like a film in a camera, the retina acts as the receiver of the moving image and transmits it down the line to the brain.
Even after this description there are some parts that have not been mentioned. Overall, the eye's make up is similar to an onion. It has several layers more correctly referred to as 'coats.' which contain and feed the important internal functions. One part of the latter is the iris, that fascinating circle of colour so popular with poets as well as opthamologists. Last, but by no means least, is the vitreous humour, a jelly like substance occupying the largest space within the eyeball and in a sense keeping it inflated.

Important Inherited Eye Diseases.

There are common diseases of the eye and there are important diseases of the eye, but fortunately no common important diseases of the eye.Thats common in the sense of affecting a large portion of dogdom. That's not to say that when any of them do occur they're not significant, because they are to the individual sufferer and for the owner and breeder of the dog.
Having said that, one of the better known inherited eye diseases is referred to as PRA. These letters stand for Progressive Retinal Atrophy, a form of worsening blindness affecting the light sensitive part of the eye.
    Two other worrying conditions occur in the sam area and can be equally blinding but are not progressive (meaning advancing) One is called Collie Eye Anomaly and the other Retinal Dysplasia; and this is where we get the problems with terminology.
    Much as expected, the first affects collie breeds and is seen as a distortion of the normal anatomy of the retina and deeper structures. It's called an 'anomaly' because its appearance is of gross irregularity, even to the point of holes of pockets appearing where they certainly shouldn't be. Retinal Dysplasia, sometimes called 'folding' is different again. Put crudely it appears much as a room wall looks after the work of a poor quality paper hanger ~ bubbled.
    As described in structures and functions, further forward in the eye lies the lens. The dog curiously enough, doesn't need the lens for seeing; it doesn't read newspapers much, watch much TV, or drive a car. Most seeing is done by the focusing effect of the cornea; its only for lots of accurate close work you need the lens activity. Never the less, if there is any distortion or opacity in the lens sight can be severely upset. One such affliction is cataract.
    Cataract is the clouding of the lens and when taken to the extreme looks as though the pupil has become bluish or grey, or even the texture of mother of pearl. Inherited cataract is seen in a large number of breeds and can be non progressive, and therefore minimally sight affecting, or can be progressive and blinding.

Need I be worried?
    Most breeds have some eye abnormalities, of greater or lesser importance. Understandably the more abnormality is looked for, the more is found, so there is little room for complacency. At the same time there is absolutely no point in burying ones head in the sand and pretending that it will go away or that it doesn't exist. Far better to get that litter, or that bitch you've always fancied having pups from, checked sooner rather than later

How do I get my dogs eyes examined?
     There are 40 or so BVA panelists throughout the UK and their names and locations will be known to practicing vets. Should you need to have your dog registered under the eye scheme, first consult your own vet, who may wish to carry out the initial examination. He or she will be able to tell you about the next steps:  making an appointment with the panelist and taking the dogs registration documents with you; you need to have time in hand for the journey~ it may mean going 50 or more miles, and once there having to wait while drops are put in the dogs eyes and allowing them time to work to make the pupil large enough to see all the structures within.