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Why have them?
Eye diseases are important. They can be obvious to owners, or they can result in blindness which can be distressing, or they can result in pain. Unfortunately some eye diseases are common in certain breeds. Checking dogs for eye disease is commonly practice all round the world.
1. Focal light This gives a bright, concentrated light source. It is used to check the pupil response, the cornea and the iris.
2.Slit Lamp This provides magnification, with a variable slit beam of light. It is extremely useful to examine the eyelids, cornea, aqueous (fluid of the eye), iris, lens, and the anterior portion of the vitreous ( jelly of the eye). Using this machine may enable the detection of early cataracts or small lesions.
3. Voroscope This is ideal for checking the eyelids and the openings of the tear ducts. It enables a magnified view with both hands free to move the eyelids.
4. Indirect Ophthalmoscope A light source and a hand lens allows examination of the fundus (retina and optic nerve). A large area is seen at any one time.
5. Direct Ophthalmoscope This hand held item is used for a magnified look at the fundus. It can also be used to fully examine the edges of the retina. Using the two types of ophthalmoscope maximises the view I get of the retina and optic nerve. Some diseases are more obvious when viewed with one type versus the other type.
Examining the Eye
The front of the eye (eyelids, cornea, anterior chamber) is examined with the focal light. The pupil responses are checked, a normal pupil should become smaller when a bright light is shone into the eye. The other pupil also becomes smaller.
Drops to dilate the pupil are then put in. These are short acting (3 to 5 hours), and unlike in man, they do not significantly affect the dog's vision. They take at least 10 to 15 minutes to dilate the pupil.
The eyelids, cornea, anterior chamber, iris and the conjunctiva with a slit lamp are then checked. This gives us a magnified (10 to 25 times) image of these structures. We may see extra eyelashes, entropion, ectopic hairs, corneal lesions, persistent pupillary membranes, iris or anterior chamber or conjunctival problems.
The voroscope is used to recheck the eyelids, looking for extra eyelashes and also to check the openings of the tear ducts that are on the inside corner of the eyelids.
After the pupils have been dilated, the lens is checked for cataracts with the slit lamp. Using this magnification, very early cataracts may be detected.
The retina and the optic nerve are then checked with two types of ophthalmoscopes. A indirect ophthalmoscope gives us a look at a large area of these tissues, then the direct ophthalmoscope is used to examine the retina and optic nerve in greater detail.
Internationally acceptable certificates are given. All problems are noted on this certificate. It is up to the individual breeder and the breed club to decide whether to use this animal at stud.
Dogs should be examined before breeding then each year until 7 to 8 years of age. Some diseases are not apparent until later in life, e.g. PRA. Therefore a final clear certificate can only be given at this late stage.
All the information gathered is treated as confidential. A report can be made to the club, but only information on the numbers and the types of conditions seen are reported. No dog or breeder can be identified.