Disorders Of Anterior Uvea Flashcards
Iris anatomy
Posterior pigment epithelium
Stroma
Muscles - dilator, sphincter
Vascular tunic of the eye
Iris
Ciliary body
Choroid
Purpose of iris
Separating the anterior and posterior chamber
Controls amt of light entering eye
Color and pupil shape vary on species
Layers of pupil/eye
Ciliary zone
Collarette - not visible in all dogs, separate ciliary and pupillary zone
Central pupillary zone
Pupillary border
Largest potion of anterior uvea
Ciliary body
Pars plicata - anteriorly iris
Pars plana - posteriorly (retina)
Function of ciliary body
Aqueous humor production - ciliary process
^drainage - iridocorneal angle
Lens accommodation - Zonules (suspensory ligament of the lens)
Iris +ciliary body
Blood aqueous barrier
Posterior iris epithelium, iris vessels, nonpigmented ciliary body epithelium
Non inflammatory diseases
Heterochromia irides
Merle ocular dysgenesis
PPM
Iris hypoplasia
Iris coloboma
Uveal cysts
Iris atrophy
Iris nevus
Heterochromia irides
Different colors within one iris or between two irides
Sole manifestation of ocular color dilution in breeds
Can be component of ocular merling - accompanied by multiple ocular anomalies
Merle ocular dysgenesis
Microphthalmia
Dyscoria (shape)
Corectopia (off center)
Iris hypoplasia
Heterochromia irides
Cataract
Staphylomas
Retinal detachments
PPM
Breeds/significance of Merle ocular dysgenesis
Australian shepherds, Great Danes, collies, dachshunds
Severity of lesions correlates with amt of white in coat /fur
Aussies - autosomal recessive inheritance
PPM
Persistent pupillary membranes
Remnants of BV (supply during development) remain
Normal strands are gone 6 weeks postpartum
Common in basenji, corgi, mastiff, chow
Location of PPM
Iris to Iris
Iris to lens (cataract)
Iris to cornea (corneal opacities)
Iris hypoplasia
Thinning of iris tissue
Partial or full defects
- muscles - prevent pupil from constricting/dilating
Can be seen alone or with other anomalies
Iris coloboma
Lack of iris tissue
Typical @6 o’clock vs atypical (any other location)
Can present by itself or with others like lens, optic nerve, retinal colobomas
uveal cysts
Common in dogs
Posterior iris epithelium and inner ciliary body epithelium are common locations
Breeds - Boston’s, retrievers - GRU
Iris atrophy (senile)
Age related thinning of iris tissue - iris stroma, pupillary margin will eventually prevent movement
Animals may exhibit sensitivity to /squinting in light
Iris nevus
Proliferation of melanocytes - well demarcated, flat or slightly elevated
Usually not progressive but have potential to undergo malignant trans formation- cats
Can be challenging to differentiate from melanoma
Neoplastic diseases
Melanocytic neoplasia
Uveal melanoma - dog and cat, horse
Iridociliary epithelial neoplasia
Metastatic neoplasia
Melanocytic neoplasia
Most common primary intraocular neoplasia
Melanocytoma - benign
Melanoma = malignant
Raised mass/lesion og from iris or CB
Pigmented = uveal cyst
Non pig = amelanotic melanoma
Uveal melanoma - dog
Typically benign
Locally invasive - secondary uveitis /glaucoma
Retrievers and GS
Uveal melanoma - cats
Feline diffuse iris melanoma (FDIM)
Malignant - raised, pigmented, can interfere with pupillary movement and secondary glaucoma
Can metastasize to liver/lungs
Uveal melanoma - horse
Typically benign
Locally invasive, can lead to uveitis & secondary glaucoma
Common in older horses/Arabians
Treating Melanocytic neoplasia
Diode laser therapy
Iridectomy
Enucleation
Addition Melanocytic treatment for cats
Thoracic radiographs
Abdominal ultrasound
FNA lymph nodes
Iridiociliary epithelial neoplasia
Ciliary body adenoma - common
Pink, vascular mass - usually visible behind pupil
Middle aged to older animals
Locally aggressive - TX is enucleation in most cases
Metastatic neoplasia
Lymphoma - most common
Can present as subtle uveitis or mass lesions
Poor long term prognosis for eye or patient
-if presents in eye, its likely the cancer is in other parts of the body
