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Band Keratopathy
Cornea
1. Clinical Analogy & Introduction
Exam pearl
- Clinical Analogy: Imagine the cornea as a pristine glass window. Band keratopathy is like limescale (calcium carbonate deposit) that builds up on this window - starting from the edges (3 and 9 o'clock, corresponding to the palpebral fissure where CO₂ evaporates most) and slowly creeping centrally, obscuring the view. The "band" configuration is not random; it mirrors the zone of maximum tear film evaporation and CO₂ loss, making the aqueous humor locally more alkaline - the perfect environment for calcium to precipitate out of solution, exactly as limescale forms where water evaporates.
Introduction
- Band keratopathy (BK), also termed calcific band keratopathy or band-shaped keratopathy, is a chronic degenerative condition of the anterior cornea characterised by the deposition of calcium hydroxyapatite Ca₁₀(PO₄)₆(OH)₂ within Bowman's layer, the epithelial basement membrane, and the superficial corneal stroma.
- It manifests clinically as a horizontal, grayish-white, chalky band traversing the interpalpebral zone of the cornea, characteristically sparing the limbus on either side.
Key Points
- Calcium deposition is favoured in the interpalpebral zone by carbon dioxide loss with local pH rise, together with tear evaporation and concentration of calcium and phosphate, reducing calcium-phosphate solubility.
- Calcium deposits typically involve the epithelial basement membrane, Bowman's layer, and superficial anterior stroma; they may initially appear in the epithelial basement membrane and anterior surface of Bowman's layer.
- Band keratopathy typically spares the limbus, leaving a sharply demarcated lucent zone; this is characteristic but not pathognomonic.
- Classification: primary or idiopathic; secondary to chronic ocular disease or injury, systemic metabolic disease, medications or chemical exposure, or hereditary disorders.
2. Definition & Historical Perspective
Historical Milestones
Historical Milestones
- 1840s: Band keratopathy first described in patients with chronic uveitis and end-stage ocular disease
- 1900s: Association with hypercalcemia and systemic diseases recognised
- 1954: Ethylenediaminetetraacetic acid (EDTA) chelation for band keratopathy was reported by Breinin and DeVoe.
- 1990s–2000s: Phototherapeutic Keratectomy (PTK) with excimer laser emerged as an alternative
- 2010s onwards: Combination approaches using ethylenediaminetetraacetic acid (EDTA) chelation, phototherapeutic keratectomy (PTK), and amniotic membrane transplantation (AMT) have been reported.
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Keep reading Band Keratopathy
16 more sections are included with the Clinical plan.
- Anatomy of Bowman's Layer - Surgical & Pathological Relevance
- Etiopathogenesis & Classification
- Pathophysiology - Mechanism of Calcium Deposition
- Clinical Features & Slit Lamp Findings
- Grading Systems
- Investigations & Imaging