Uveal disease: what can go wrong with the uvea in dogs and cats? (Proceedings)
Diseases of the uvea
Diseases of the Uvea
• Developmental
• Degenerative
• Infectious
• Immune –mediated
• Idiopathic
• Inflammatory
• Metabolic/ Nutritional
• Toxic
• Traumatic
• Neoplastic
Developmental diseases
• Incomplete Development
• Maldevelopment
• Incomplete regression of embryonal tissues
Color variants
• Subalbinism
o Dilution not absence of pigment
o Blue eyes- lack pigment in stroma but overlies pigmented neuroectoderm
o True Albino- pink or red iris due to complete lack of pigment
• Heterochromia Iridis
o Multiple colors within one iris or between eyes
o Component of merling gene
o Can accompany other iridal abnormalities
Persistent pupillary membranes
• Pupillary membranes should atrophy by 6 weeks of age
• PPMs arise from the collarette region of the iris
• Iris-to-iris, iris-to-cornea, iris-to-lens
• Basenji: heritable PPMs
• Corgi, Chow, Mastiff: familial PPMs
Aplasia/ hypoplasia
• Aniridia: total absence of iris tissue
• Iris Hypoplasia
o Notch Coloboma: affects the pupil margin
o Pseudopolycoria: one or more holes in iris body
o Iridodiastasis: defect in iris base
Iris hypoplasia
Pupillary abnormalities
• Polycoria: one or more extra pupillary opening
o Each opening has its own functional sphincter and dilator muscles
o Rare
• Corectopia: abnormal position of pupil
• Microcoria: congenital miosis due to lack of dilator muscle
Congenital uveal cysts
• Originate from persistence of space between the two layers of neuroectoderm or primary optic vesicle
• Fluid accumulates between these epithelial layers
• From pars plicata of the ciliary body or pupillary margin of the iris
Anterior segment dysgenesis
• Doberman, Saint Bernard
• Autosomal recessive trait
• Primary defect in formation of the neuroectodermal optic cup causing abnormal induction of mesenchyma
• Congenital blindness
• Clinically: microphthalmia, opaque corneas, absent anterior chamber, undifferentiated iris and ciliary body, absent or rudimentary lens, hyaloid artery remnants, retinal dysplasia, retinal separation
Collie eye anomaly
• Patchy to diffuse choroidal hypoplasia is the hallmark of CEA
• Inherited as an autosomal recessive trait
• Results from failure of induction by a defective RPE (abnormal pigmentation)
• Similar syndrome in Aussies, Border Collies, Shelties, and other color dilute breeds
Collie eye anomaly
• Lesions are dorsotemporal, bilateral, asymmetrical
• Generally at the junction between tapetal and nontapetal fundi
• Fewer, wider, and abnormal arrangement of choroidal vessels, increased sclera is visualized
Degenerative diseases
• Senile Iris Atrophy
o Progressive thinning of iris stroma
• Secondary Iris Atrophy
• Essential Iris Atrophy
Uveitis
• Massa KL, et al. Causes of Uveitis in dogs: 102 cases (1989-2000). VO 5(2); 2002: 93-98
o Infectious: 17.6%
o Immune-mediated/ Idiopathic: 57.8%
o Neoplasia: 24.5%
• Clinical Signs
o Aqueous flare: 86%
o Corneal Edema: 61%
o Keratic Precipitates: 11%
o Systemic Signs: 56%
Canine infectious uveitis
• Algal
o Prototheca
• Fungal
o Blastomyces
o Cryptococcus
o Coccidioides
o Histoplasma
• Viral
o Adenovirus
o Distemper
o Herpes
o Rabies
• Parasitic
o Diptera (Ophthalmomyiasis interna posterior)
o Dirofilaria (Ocular filariasis)
o OLMs (Toxocara, Balisascaris)
• Protozoal
o Leishmania
o Toxoplasma
o Rickettsia
o Ehrlichia
• Bacterial
o Brucella canis
o Lymes disease
o Leptospirosis
o Septicemia
Feline infectious uveitis
• FIV
• FeLV
• FIP
• Bartonella
• Toxoplasma gondii
• Cryptococcus
• Histoplasma
• Coccidiosis
• Candida albicans
Uveodermatologic syndrome
• Vogt-Koyanagi-Harada in humans
• Young adults (mean age 2.8 years)
• Akita, Samoyed, Husky, Sheltie
Uveodermatologic syndrome
• Ocular signs can precede dermatologic signs
• Ocular clinical signs
o Bilateral anterior or panuveitis, uveal depigmentation, retinal separation, blindness, cataract formation, iris bombe, glaucoma
• Dermatologic clinical signs
o Vitiligo of eyelids, nasal planum, lips, foot pads
o Poliosis
Uveodermatologic syndrome
• Immune mediated destruction of ocular and dermal melanocytes
• Histopathology reveals interface dermatitis with primarily a lichenoid pattern
o Large histiocytic cells, plasma cells, and small mononuclear cells
• Treatment
o Topical and systemic corticosteroids
o Systemic immunosuppressives (Immuran)
Lipid aqueous
• Often unilateral, sudden onset
• Skim milk appearance
• Systemic hyperlipidemia
o Disruption of BAB
o DM
o Hypothyroidism
o Hepatic disease
o Pancreatitis
o Breed- Schnauzer
Lens-induced uveitis
• Pathophysiology
o Weakly antigenic alpha-crystallin is normally released from the lens capsule inducing a T-cell tolerance to low antigen levels
o Sudden release of large amounts of lens cellular and membrane protein exceeds normal tolerance and leads to LIU
Lens-induced uveitis
• Phacolytic
o Lens protein leakage
o Decreased release of antigen
o Phagocytosis of protein by macrophages
o No release of cytokines and IL-1
• Phacoclastic
o Lens protein and membrane proteins are presented
o T- cell response is activated by MHC-II presenting cells
o Release of cytokines and IL-1
o Chemotaxis of neutrophils
Pigmentary uveitis
• Golden Retrievers
• Bilateral disease
• Clinical signs: pigment dispersion in anterior chamber, dark thickened iris, pigmented anterior lens capsule, posterior synechia, cataract formation, glaucoma
• Uveal cysts may be associated
Traumatic hyphema
• Occurs when uveal or retinal vessels are torn or disrupted
• Most commonly due to head trauma
• Concurrent injuries
o Orbital fractures
o Eyelid or facial trauma
o Retinal detachments
Traumatic hyphema
• Additional diagnostics
o Physical examination
o Ocular ultrasound
o Skull radiographs
• Treatment
o Topical and systemic corticosteroids
o Atropine???
o TPA???
• Resorption can occur in 7 to 21 days, consolidation of blood should be observed in 8 days
Primary uveal neoplasia
• Benign
o Melanocytoma
o CB adenoma
o Cavernous hemangioma
o Ciliary body hemangioma
o Medulloepithelioma
• Malignant
o Melanoma
o Melanocarcinoma
o CB adenocarcinoma
o LSA
o Feline Sarcoma
o Iridal HAS
o Iridal Leiomyosarcoma
Secondary uveal neoplasia
• Hematogenous route of metastasis
• Bilateral is more common
• LSA and HSA is most common
• Cutaneous or oral melanoma, SCC
Canine uveal neoplasia
• Melanocytic neoplasms (melanomas)
o Most common primary intraocular neoplasm in the dog
o Locally invasive, Low incidence of metastasis (4%)
o Arise in anterior uvea
o Iris and Ciliary body
o Older dogs (8-10 years)
Canine uveal neoplasia
• Clinical Signs of Melanoma
o Darkly pigmented nodular mass
o Diffuse infiltration is less common in the dog
o Extending through the pupil
o Displacing the iris anteriorly
o Dyscoria
o Free floating pigment in anterior chamber
Canine uveal neoplasia
• Ciliary Body Adenoma/ Adenocarcinoma
o 2nd most common
o Low rate of metastasis, locally extensive
o Originate from non-pigmented or pigmented epithelium
• Medullepithelioma
o Young dogs
o Benign, low metastasis, local extension
o Originate from neuroectoderm cells
Feline uveal neoplasia
• Melanoma
o Most common primary tumor in the cat
o Hyperpigmentation of iris, irregular texture or iris, multifocal to diffuse appearance, infiltrate ICA, pigmented floaters in anterior chamber, increased IOP
o Malignant transformation
o Pulmonary and hepatic metastasis
Feline uveal neoplasia
• Dubelzieg VO 1(1) 1998 p25-29.
o Retrospective study of 32 cats with histologically confirmed diffuse uveal melanoma
o Affected cats did have a decreased survival rate
o Cats with extensive disease had the lowest survival rates
Feline uveal neoplasia
• Trauma- associated sarcoma
o 2nd most common
o Highly malignant
o Risk factors include trauma to lens, chronic uveitis, intraocular surgery???, CBA
o Early exenteration recommended
Feline uveal neoplasia
• Lymphosarcoma
o Pink to white mass in the anterior chamber, "D" shaped pupil
o Uveitis
o Secondary glaucoma
o FeLV-antigen positive cats
o Aqueocentesis or BM aspirate can be diagnostic
Differentials for Uveal Neoplasia
• Benign uveal proliferations
o Ectropion uvea, Rubeosis iridis, Iris hyperpigmentation, Nevi/freckles
• Uveal cysts
• Uveal granulomas
• Extraocular tumor with intraocular extension
• Perforating ocular trauma with uveal prolapse
Questions
