What is Spheroidal Degeneration of the Cornea (SDC)?

What is Spheroidal Degeneration of the Cornea (SDC)?

Spheroidal degeneration is a degenerative ocular condition characterized by the deposition of yellow-brown, globular proteinaceous material in the cornea and/or conjunctiva.
The term “spheroidal” implies a nearly spherical but imperfectly round appearance.

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🔍 Alternate Names

• Climatic Droplet Keratopathy (CDK)
• Bietti’s nodular degeneration, Fisherman’s keratopathy, Labrador keratopathy
• Typically linked to UV exposure, chronic dryness, wind, and aging

 

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🧬 Classification

TypeNameLocationCause

Type I	Primary corneal type	Peripheral cornea (3 & 9 o’clock)	UV, wind, microtrauma, aging
Type II	Secondary corneal type	Any corneal area	Post-inflammatory (e.g., keratitis, NV)
Type III	Conjunctival type	Conjunctiva	UV exposure, usually coexists with Type I

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🧪 Clinical Features

• Subepithelial yellow-brown spheres
• With progression: Bowman’s layer and stroma involved
• Can cause blurred vision if central cornea is affected
• Conjunctival lesions may cause discomfort or foreign body sensation

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🧬 Histopathology

• Hyaline material deposits beneath the epithelium
• Extends to Bowman’s layer and stromal matrix in advanced stages

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💊 Treatment

• Conjunctival lesions: Can be surgically excised if symptomatic
• Corneal lesions: Treated with
  → Superficial keratectomy or penetrating keratoplasty
  → Recurrence possible

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✅ Summary

• UV- and age-related condition involving globular deposits in cornea or conjunctiva
• Classified into 3 types (corneal primary, corneal secondary, conjunctival)
• Vision-threatening in advanced stages
• Surgery can help, but recurrence risk remains