Page 574 - ONLINE PROCEEDING BOOK WSAVA 2017
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An Urban Experience
Anophthalmia is lack of eyeball. Sometimes the remnants of an eyeball is hidden underneath the conjunctiva (cystic eye). The diagnosis of a too small eyeball or lacking eye/cystic eye can be made/con rmed by the use of ultrasound.
Cornea:
Corneal stromal dystrophy: Is lipid and/or mineral deposits in the corneal stroma, often bilaterally.Most commonly seen in dogs. It often manifests as opaque shadow in the axial/paraxial cornea. The condition can be congenital, but usually develop later in life.
Corneal endothelial dystrophy: Is reported to be inherited in the Chihuahua, Dachshund and Boston terrier. It manifests in middle aged- older individuals. The clinical signs are whitish-bluish opaque cornea, usually staring in the axial cornea. With time, it usually involves the entire cornea.
Anterior chamber:
Persistent pupillary membranes (PPM) are congenital remnants of the pupillary membranes. These should normally regress by the time of the eyelid opening.
Both cats and dogs can be affected. The condition can be seen as strings from iris-iris, iris-lens, iris-cornea, plaque on the corneal endothelium and/or anterior lens capsule, or combinations of the former. Iris-cornea PPM can be accompanied by opaci cation of the cornea. If pronounced it can compromise vision/ lead to blindness. If attached to the anterior lens capsule it can result in secondary cataract.
Iris hypoplasia/coloboma: Is due to dysgenesis of the iris stroma resulting in a thinner iris than normal or holes/complete lack of iris tissue. Photophobia can be a consequence in pronounced cases.
Lens
Microphakia: Is a congenital condition where the lens is smaller than normal. It can be accompanied by other abnormalities such as cataract and microphthalmia. As the lens is crucial for normal development of the eye, congenital aphakia is only seen in association with cystic eyes.
Lens coloboma: Lens coloboma is a consequence of focal lack zonula zinni attaching to the lens, resulting in a  attening of the lens curvature.
Lenticonus: Is a bulging of the lens surface, most commonly the posterior aspect of the lens, but on rare occasions it can affect the anterior aspect of the lens.
Cataract: Is an opacity of the lens. It can be either congenital or developmental. Congenital cataracts usually involves the lens nucleus, but can evolve to affect the cortex. Developmental cataracts usually involves the lens cortex initially but can evolve to affect the nucleus
and/or the entire lens (total cataract). Developmental inherited cataracts can develop later in life varying with breed and form of cataract. It can develop to complete cataract. Other etiologies for cataract such as metabolic, trauma, toxic etc have to be excluded before the diagnosis of inherited cataract is made.
Persistent hyperplastic tunica vasculosa lentis/ Persistent hyperplastic primary vitreus (PHTVL/ PHPV): is a congenital condition in which there is an abnormal regression of the vascular system nourishing the lens during its development. This regression should be complete by the opening of the eyelids. The condition is reported to be inherited breeds such as pinscher- breeds, the Staffordshire bullterrier amongst others. The severity of the conditions varies from pigmented spots on the posterior lens capsule to lenticonus/intra-lenticular bleeding/ plaque on the posterior lens capsule and cataract.
The retina and the optic nerve head:
Retinal dysplasia (RD): Is due to uneven growth of the two ectodermal layers of the retina (neuro retina and the retinal pigment epithelium). Focal/multi focal RD is observed as elevated greenish streak-like
areas in the retina. Geographic RD is a horseshoe shaped-round greenish elevations in the retina, most commonly located along the dorsal retinal vessel. In total retinal dysplasia the retina has detached leading
to blindness. Histologically RD can be observed as rosettes. RD is reported inherited in several dog breeds including retrievers and spaniels. The funduscopic signs usually become less pronounced with age, although
in the English springer spaniels progression to retinal detachment has been reported.
Collie eye anomaly (CEA): Mainly seen in collies and collie-related breeds. The condition comprises optic nerve head coloboma, choroid hypoplasia/ chorio
retinal dysplasia (CH) and complications such as retinal detachment/intraocular hemorrhage. The optic nerve colobomas, may involve parts of or the entire optic nerve head. Extensive colobomas may be associated with secondary retinal detachments. Choroidal hypoplasia
is an abnormal development of the choroidal vessels, usually seen as distorted/absence of vessels lateral to the ONH in the tapetal areas. In non-merle dogs, these areas are usually covered by pigment (“Go normal”). CEA is reported to be a polygenic disease, and a commercial gene test exists for the CH part of the CEA-complex.
Rod-cone dysplasias/dystophies (RCD): The photoreceptor dysplasias usually present early in life, often as early as 5-6weeks on electroretinographical (ERG) examination. In the progressive retinal atrophies (PRA), the photoreceptors develop normally initially, but degenerate later in life. Early forms of PRAs are evident from about 2 years of age, whereas the late forms may
42ND WORLD SMALL ANIMAL VETERINARY ASSOCIATION CONGRESS AND FECAVA 23RD EUROCONGRESS


































































































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