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 Lenticonus Courtesy of Dr. Dubielzig (COPLOW) 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 Congenital cataract Courtesy of Dr. Dubielzig (COPLOW) 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/ cross- hatching 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! [email protected].