Pathology of the lens Carol Naranjo, LV, DACVP, DECVP, PhD IDEXX Laboratories
Embryonal development Gelatt s Veterinary Ophthalmology, 5th Ed.
Normal histology Lens capsule Anterior > posterior Lens cortex Lens epithelium and lens bow Lens nucleus Artifact!
Lens bow Anterior lens capsule Posterior lens capsule
Congenital conditions Aphakia Microphakia Lens coloboma Dr. Dubielzig (COPLOW) Spherophakia Lenticonus/lentiglobus
Courtesy of Dr. Dubielzig (COPLOW) Lenticonus
Cataract Any opacification of the lens Various classifications Etiology: Senile, hereditary, diabetic, toxic Secondary: intraocular inflam, retinal degeneration, glaucoma, neoplasia Extension of lens involvement Some variation b/w clinical-pathological assessment Location
Congenital cataract Abnormal position or lysis of the nucleus. Dysplastic changes in the lens capsule Duplication, wrinkling Posterior migration of lens epithelium Fetal vasculature anomalies
Courtesy of Dr. Dubielzig (COPLOW) Congenital cataract
Cataract - location Subcapsular anterior: Proliferation of LEC LEC fibrous metaplasia Collagenous mb
Cataract - location Subcapsular posterior: Migration of lens epithelium Proliferation, fibrous metaplasia, collagen membranes
Cataract - location Cortical: Early/incipient: not always detected Mature: Bladder cells Morgagnian globules Intumescent: Lens swelling Morgagnian globules throughout the cortex
Intumesent cataract Courtesy of Dr. Dubielzig (COPLOW)
Cataract - location Cortical: Hypermature: Lens swelling Mineralization Liquefaction Lens capsule wrinkling Morgagnian: Cortex liquefaction, only the nucleus remains Nuclear: hard to detect histologically
Mineralization
Cortical liquefaction
Lens capsule wrinkling
Morgagnian cataract
Resorbed cataract
Cataract after trauma Anterior or posterior subcapsular / cortical Lens capsule rupture: Intralenticular cells: MO, PMNn, RBC, fibroblasts, blood vessels Margins of the lens capsule: Proliferating LEC entrapping the edges of the capsule Spindle cells associated with synechiae Frayed capsule edges with inflammatory cells. Scrolling of the edges of lens capsule.
Cataract after trauma Inflammation w/ lens capsule rupture (phacoclastic uveitis): Bland granulomatous inflammation LP uveitis Lens epithelium: spindle cell metaplasia, proliferation and migration BM-like material Myofibroblastic phenotype Lens luxation
Phacoclastic uveitis
Courtesy of Dr. Dubielzig (COPLOW) Courtesy of Dr. Dubielzig
Post-cataract surgery
Post-cataract surgery lens fiber regrowth
Lens luxation Separation of lens from the zonular attachment Subluxation Anterior luxation Posterior luxation
Lens luxation Primary: Zonular ligament dysplasia Marfan syndrome Secondary: Uveitis Trauma Glaucoma Hypermature cataract Senile
Diagnosing lens luxation Clinical diagnosis Grossly (trimming): Lens displacement Vitreous liquefaction Distorted angle of the iris leaflet ( dogleg ) Attenuation of the corneal endothelium (axially) Atrophy of ciliary processes Position of the lens on the histo slide
Entrapment of the lens
Dog leg iris
Endothelial cell attenuation
Ciliary processes atrophy
Diagnosing lens luxation (non-specific) Cornea: Edema/corneal ulceration, keratitis, collagenolysis Retrocorneal membranes Retinal detachment Glaucoma: Pupillary block PIFM Inflammation, anterior segment of the globe
Zonular ligament dysplasia Terrier breeds (JRT) Chinese crested dog, Shar Pei, Australian blue Heeler Many breeds w/ ADAMTS17 mutation Younger than other dogs with lens lux Important for the 2nd eye! Morris and Dubielzig, 2005
Zonular ligament dysplasia Thick lamellar eosinophilic membrane w/ crosshatching pattern Intermittent change Staining properties; PAS-positive (normal also +ive) Blue with Masson s trichrome (normal is red) Negative for Verhoeff s elastin stain (normal is +ive)
Special stains PAS Masson s trichrome Normal, from: Morris and Dubielzig, 2005
Primary lens luxation Inflammation in anterior segment: Mononuclear Some PMNs can be seen Pigmentary changes: Melanophages and pigment dispersion Hypertrophy/hyperplasia of post mid-iris epithelium Loss of pigment epithelium in pupillary margin
Alario et al, 2013
Thanks! Carolina-Naranjo@idexx.com