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