Corneal Pigmentation – Decoded

 

Corneal Pigmentation

Type of Pigment	Name of Deposit	Disorder	Location in Cornea
Iron	Stocker’s line	Pterygium	Epithelium
	Hudson-Stahli line	In old age	Epithelium
	Ferry’s line	Filtering bleb	Epithelium
	Fleischer’s ring	Keratoconus	Epithelium
	Coat’s white ring	Previous Metallic foreign body injury	Bowman’s layer
		Siderosis	Stroma
		Blood staining of cornea	Stroma
Copper	Kayser-Fleischer ring	Wilsons’s Disease	Descement’s membrane
Melanin	Krukenberg’s spindle	Pigment dispersion syndrome	Endothelium
Silver		Argyrosis	Stroma
Gold		Chrysiasis	Stroma

Stockers line:

• Iron deposition line in the corneal epithelium, located at the corneal leading edge of a pterygium.
• present at the leading edge of non-growing pterygium
• yellow to golden brown.

Hudson-stahli line:

• Iron deposition line in the corneal epithelium, which commonly seen in the junction between middle and lower third cornea (corresponding to the line of lid closure).
• Often seen in elderly.
• bilateral & symmetric
• Causes no symptoms or clinical significance.

Ferry’s line:

• Seen in front of filtering bleb in glaucoma.
• Filtering bleb is a blister of conjunctiva resulting from glaucoma surgery by which a flap of sclera is created in the eye wall, allowing aqueous humor to percolate out of the eye and underneath the conjunctiva, thus lowering intraocular pressure. To know more about it, check this MedRounds link.

Coat's White Ring:

• A form of iron deposit at the level of Bowman's layer.
• Clinical features:
  • Asymptomatic
  • Small, granular, oval white ring
  • Commonly associated with previous corneal foreign body injury
• Requires no treatment.

Fleischer Ring :

• Partial or complete iron deposition ring in deep epithelium encircling the base of the cone.
• Formed when hemosiderin (iron) pigment is deposited deep in the epithelium
• Characteristic in eyes with keratoconus.

Kayser-Fleischer ring:

• Deposits of copper producing golden-brown discoloration in the peripheral cornea. Their earliest appearance consists of colored crescents at the superior and inferior quadrants of the cornea that eventually become circumferential.
• The Kayser-Fleischer ring is the single most important diagnostic sign in Wilson's disease
• It is found in 95% of patients.
• Virtually all patients with Kayser-Fleischer rings have neurological manifestations.
• Diseases associated with Kayser-Fleischer rings

1. Wilson's disease
2. primary biliary cirrhosis
3. chronic cholestasis
4. cryptogenic cirrhosis

Krukenberg’s spindle:

• a vertically oriented deposition of pigment on the posterior endothelial surface of cornea.
• Seen in Pigment dispersion syndrome.
• In Pigment dispersion syndrome, the iris is bowed posteriorly causing it to rub against the lens zonules. this results in the loss of pigment epithelium& hence the transillumination and the endothelium deposition of pigment. The vertical orientation of pigment is due to conventional current.
• Pigment granule accumulation in the trabecular meshwork then leads to progressive trabecular dysfunction and ocular hypertension with or without associated glaucomatous optic neuropathy.About 1/3 of them develop pigmentary glaucoma.
• The classic triad of clinical signs of PDS consists of a

1. Krukenberg spindle,
2. slit-like, radial, mid-peripheral iris transillumination defects, and
3. pigment deposition on the trabecular meshwork (Sampaolesi’s line)