Pathology of the lens

Carol Naranjo, LV, DACVP, DECVP, PhDIDEXX 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!

Anterior lens capsule Posterior lens capsule

Lens bow

Congenital conditions

• Aphakia

• Microphakia

• Lens coloboma

• Spherophakia

• Lenticonus/lentiglobus

Dr. Dubielzig (COPLOW)

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

Courtesy of Dr. Dubielzig (COPLOW)

Intumesent cataract

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. DubielzigCourtesy of Dr. Dubielzig (COPLOW)

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)

PAS Masson’s trichrome

Special stains

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