Color change of the sclera: causes, symptoms, diagnosis, treatment

Focal discoloration of the sclera (focal discoloration)

It can be caused by the following reasons.

• Senile transparency of the sclera - discolored dark gray areas.
• Alkaptonuria may cause brown-black coloration (ochronosis) at the attachment of the horizontal rectus muscles and pigmentation of the auricles.
• Hemochromotosis causes a rusty brown color.
• Systemic minocycline causes a blue-grey discoloration of the paralimbal area, usually more intense between the eyelids, possibly due to the photosensitizing properties of the drug. This may be associated with pigmentation of the skin, teeth, nails, mucous membranes, thyroid gland, and bones.
• Long-term presence of metallic foreign body may cause rusty staining

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Diffuse discoloration of the sclera (diffuse discoloration)

• Yellow discoloration of the sclera is caused by jaundice.
• The blue coloration of the sclera is caused by thinning and transparency of the scleral collagen and the translucency of the underlying choroid.
• Important cases include osteogenesis imperfecta types 1-2, Ehlers-Danlos syndrome (usually type 6), pseudoxanthoma elasticum (dominant type 2), and Turner syndrome.

There may be an acquired change in the color of the sclera - blackish, dirty-gray-bluish spots (yellow sclera) - when taking certain medications, silver preparations, or using cosmetics.

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